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ONGC Placement Paper : ONGC Placement Paper Technical and GK 03 November 2012

80 Q technical 40 GK and 30 Aptitude with no negative marking held on Nov 2, 2012

1 Badami caves built by :chaulkyas

2 Which statement in correct for GSAT 10 :launched by atlas-5(actually ariane 5)

3 Olympic 2012 closing ceremony indian flagbearer : Mary kom

4 Nam summit: Iran

5 Employment scheme 2005:Mahatma Gandhi nation rojgar guarantee scheme

6 Vice president election can be disputed in:Supreme court

7 Glass etching done by : hydroflouro acid

8 Incorrect Matching of dams:

1.nagarjun dam on cauvery(is actually on Krishna)
2.hirakud dam on Mahanadi
3. Bhakranagal on Sutlej
4. One more on godaveri

9 Ants follow a line due to secretion of :pheromone (a type of hormone)

10 Duties and power of CAG :article 149

11 Writ :article 32

12 Order of precedence: supreme court,union minister,cabinet secretay,chief election commisiioner

13 Speech on Annihilation of caste:B.R.Ambedkar

14 Who was inspired by gitanjali :keats

15 Which is not an epic:ramayan,mahabharat,beuwolf,canterburry tales (cant .tales)

16 Which of following carries oxygenated blood tp heart (right/left auricle/ventricle)

17 Food poisoning bacteria: collistridum botullim

18 Khaira diese : deficiency of zinc

19 Match on port of india like pradip port,etc

20 Match on place like national cellular jail,chilka lake, one fort,etc

21 Arrange the Speed of ram, floppy ,harddisk,cache

22 WIDAL test for:typhoid

23 President ordinace valid for:6 weeks

24 President election by:50 proposer-50 selector

25 Fasting blood sugar level for: diabetes

26 Mineral found in cape comrin of which india is one of the largest producer (lignite,bauxite,etc ?)

27 Chemical compositonis of:brass,bronze,gunmetal?

28 Star moving away from earth,wavelength: increase

29 Which city is situated pn two continents?istambul

30 Which is largest producer of uranium :kazakistan

31 One question on seirre lion

32 Emerging cricketer by icc :sunil nareine

33 Negative service tax: no tax is levied

34 Which shakespear play poison was used:Hamlet

ONGC Placement Paper : ONGC Placement Paper ECE 08 November 2012

OIL AND NATURAL GAS CORPORATION LIMITED EXAMINATION OF GRADUATE TRAINEE-2012 ECE 04-11-2012

ONGC Graduate Trainee Written Test pattern
No of Sections :3
Test Duration is 3 hours.


Section :1
General Awareness:
40 MCQs having 40 Marks,
National & international affairs, books & authors, History, Polity, Science & Technology, Sports.

Section :2
Concerned Discipline/Domain/Subject: In mine ECE
80 MCQs having 80 Marks,

Section :3
Aptitude Test:
30 MCQs having 30 Marks .
Comprising of Reading Comprehension, Verbal/ Non-verbal Reasoning, Numerical Ability/ Quantitative Aptitude, Data Interpretation Time and Distance,Permutation combination Probability etc

Questions are Asking from Each Subject

Most of the ques are from communications but there are ques from analog circuits, semiconductors, transistorsetc.
comp of SSB and DSB

numerical from ADC/DAC

quantisation noise depends upon?

problem to find characteristic impedence

arrange CE,CB,CC in order of input impedence

brass is an alloy of?

whose B.W.is higher-PCM ,PAM ,PDM ,PPM

boltzman constant is proportional to

ONGC Placement Paper : ONGC Placement Paper Computer Engg questions 30 October 2012

ONGC Question Bank in Computer Science,ONGC practice questions

Multiple Choice Questions

1. A computer derives its basic strength from

(a) speed

(b) accuracy

(c) memory

(d) all of the above (Ans)

(e) None of the above.



2. Modern computers compared to earlier computers are

(a) faster and larger

(b) less reliable

(c) larger and stronger

(d) slower but more reliable

(e) faster and smaller (Ans)



3. The use of computer for business applications is attractive because of its

(a) accuracy

(b) reliability

(c) speed

(d) secret code facility

(e) All of the above (Ans)



4. A computer is capable of performing almost any task, provided that it can be

(a) coded

(b) memorized

(c) analyzed

(d) reduced to a series of logical steps (Ans)

(e) changed top mathematics equation



5. A BIT represents a

(a) decimal digit

(b) octal digit

(c) binary digit (Ans)

(d) hexa decimal digit



6. A computer has very high speed, accuracy and reliability. Its intelligence quotient could be of the order of

(a) 100

(b) 0 (Ans)

(c) 50

(d) 200

(e) 99.99



7. Computer can not do anything without a

(a) chip

(b) memory

(c) output device

(d) program (Ans)

(e) None of the above



8. A computer possesses information

(a) as directed by the operator

(b) automatically (Ans)

(c) at once

(d) gradually and eventually

(e) by truncating



9. Pick up the false statement

(a) computer can manipulate both numeric and non-numeric symbols

(b) computer errors can usually be traced to faulty programs or inaccurate input data

(c) the facts or informational raw materials represented by numeric and non-numeric symbols are called information (Ans)

(d) the space in the primary storage section is divided into four areas: input, working, storage, output and program storage.

(e) Information is the relevant knowledge that results from the processing and arranging of data in an ordered and useful form.



10. Processors of all computers, whether micro, mini or mainframe must have

(a) ALU

(b) primary storage

(c) control Unit

(d) all of the above (Ans)

(e) None of the above.



11. Pick up the correct statement about computers

(a) computers process data with human intervention after the program has been fed

(b) all comparisons are made in the control section

(c) the arithmetic-logic section of the CPU selects, interprets and executes the program steps.

(d) the secondary storage devices are usually connected on line to the CPU but for accepting data from them or returning data to them, human intervention is required

(e) computers have the built-in ability to obey different types of instructions. (Ans)



12. Real time computing is possible because of the following characteristic of computer

(a) storage capability

(b) high speed (Ans)

(c) accuracy

(d) versatility

(e) automatic in execution



13. Pick out the wrong statement about modern computer systems

(a) these are simple and easy to take care of

(b) even beginners, untrained persons can safely handle them (Ans)

(c) they require a highly disciplined approach

(d) it is important to understand the proper overall procedures must be followed

(e) the negligent use of a computer system will almost always introduce time bombs into the system.



14. A collection of eight bits is called:

(a) byte (Ans)

(b) word

(c) record

(d) file

(e) None of the above



15. Choose the incorrect statement about micro computers, mini-computers, etc.

(a) a microcomputer can be placed on a single silicon chip

(b) a minicomputer can have more processing capability than a mainframe model

(c) a microcomputer chip performs the arithmetic-logic and control functions of a microcomputer

(d) ROM chips may be used in micros ;to permanently store program instruction

(e) most micros use rigid disk storage devices rather than floppy disk drives. (Ans)



16. Control Unit of a digital computer is often called the

(a) lock

(b) nerve center (Ans)

(c) ICs

(d) all of the above

(e) None of the above



17. Pick up the correct statement

(a) most mainframes are 48-bit machines

(b) thousands of super computers are currently being built

(c) super-computers are usually designed to process accounting applications

(d) mainframes may have multi-processor components that permit several tasks to be processed at the same instant in time (Ans)

(e) minicomputers can not use high speed buffer storage components and are thus always slower than mainframe models.



18. The following acronym recognizes the fact that "computer errors" can usually be traced to incorrect input data or unreliable programs

(a) IGO (Ans)

(b) FIFO

(c) LIFO

(d) DASD

(e) ROM



19. Group of instructions that directs a computer is called

(a) storage

(b) memory (Ans)

(c) logic

(d) program

(e) None of the above



20. Which of the following does not describe one or more characteristics of a computer?

(a) electronic

(b) external storage

(c) stored program

(d) program modification at execution (Ans)

(e) All of the above are characteristics.



21. Which of the following statements is true?

(a) the smart approach to using computers is to write programs

(b) knowledge of the system development life cycle is not important to operators who use computers without programming

(c) hands-on exposure to the computer is not helpful to those who write programs

(d) personal computer have been an important contributing factor in the movement towards using computers without programming (Ans)

(e) None of the above is true



22. Which can read data and convert them to a form that a computer can use?

(a) logic

(b) storage

(c) control

(d) input device (Ans)

(e) output device



23. Software instruction intended to satisfy a user,s specific processing needs are called

(a) system software

(b) a microcomputer

(c) documentation

(d) applications software (Ans)

(e) All of the above



24. Which kind of hardware is used the most in the input phase of a computer based information system?

(a) keyboard (Ans)

(b) printer

(c) monitor

(d) hard disk

(e) floppy disk



25. Which of the following is not a factor when categorizing a computer

(a) amount of main memory the CPU can use

(b) capacity of the storage devices

(c) cost of the system

(d) where it was purchased (Ans)

(e) speed of the output device



26. Which of the following is the most powerful type of computer?

(a) super micro

(b) super conductor

(c) microcomputer

(d) super computer (Ans)

(e) megaframe



27. Which of the following people probably has the least amount of technical knowledge ?

(a) programmer

(b) user (Ans)

(c) system analyst

(d) computer operator

(e) computer professional



28. Which kind of storage device cab be carried around?

(a) floppy disk (Ans)

(b) hard disk

(c) system cabinet

(d) hard disk drive

(e) floppy disk drive



29. Which of the following terms applies to communication between separate computer systems?

(a) computer literacy

(b) power supply

(c) applications software

(d) connectivity (Ans)

(e) None of the above



30. The Central Processing Unit (CPU) consists of:

(a) input, output and processing

(b) control unit, primary storage & secondary storage

(c) control unit, arithmetic-logic unit, primary storage (Ans)

(d) control unit, processing, primary storage

(e) None of the above



31. People typically interface with a computer based system when:

(a) information must be output

(b) data must be input

(c) information must be reviewed the computer needs a direction (or instruction) in order to process data

(d) All of the above

(Ans : e)

32. The principle advantage of the centralized approach to organizing a computer facility is :

(a) cost-effectiveness

(b) processing activities are easier to coordinate

(c) Processing activities are easier to control

(d) processing statements can be enforced

(e) All of the above (Ans)



33. The fifth generation digital computer will be

(a) extremely low cost

(b) very expensive

(c) versatility

(d) artificial intelligence (Ans)

(e) None of the above



34. To be information, data must be

(a) factual

(b) relevant

(c) news

(d) all of the above (Ans)

(e) None of the above



35. A data system for calculating measures used in statistical inference is an example of a

(a) teleprocessing system

(b) data management system

(c) computing system (Ans)

(d) All of the above

(e) None of the above



36. For the purposes of defining data needs, a responsibility area is

(a) marketing

(b) administration

(c) personal (Ans)

(d) all of the above

(e) None of the above



37. Which is widely used in academic testing?

(a) MICR

(b) POS

(c) OCR

(d) OMR (Ans)

(e) None of the above



38. Coded entries which are used to gain access to a computer system are called:

(a) entry codes

(b) passwords (Ans)

(c) security commands

(d) code words



39. A factor which might cause an individual to consider using a computer in criminal activities is :

(a) the computer,s access to large sums to money

(b) the speed with which the crime can be accomplished

(c) EFTS (Electronic Funds Transfer System)

(d) All of the above (Ans)



40. EBCDIC can code up to how may different characters ?

(a) 816

(b) 32

(c) 64

(d) 256

(Ans : e)



41. Which of the following statements is true?

(a) the installation of a computer is favorably received by all employees

(b) some form of training is necessary for employees who will work with computers (Ans)

(c) computers are portrayed solely as society,s benefactor

(d) a business person is only interested in the computer,s accuracy.





42. Which is considered a direct entry input device?

(a) optical scanner

(b) mouse

(c) light pen

(d) digitizer

(e) All of the above (Ans)



43. The daily processing of corrections to customer accounts best exemplifies the processing mode of :

(a) batch processing (Ans)

(b) real-time processing

(c) interactive processing

(d) All of the above



44. The data processing job expected to further decreases in the 1990s is that of :

(a) keypuncher (Ans)

(b) data entry clerk

(c) computer operator

(d) programmer



45. Which is a unit of measurement used with computer systems?

(a) byte

(b) kilobyte

(c) megabyte

(d) gigabyte

(e) All of the above (Ans)



46. Which of the following statements is true?

(a) analysts usually work alone and sometimes as part of a team

(b) most systems projects are completed in 6 12 weeks

(c) an analyst,s primary concern is the development of software

(d) analysts evaluate data flow through an organization (Ans)



47. In computer terminology, information means

(a) raw data

(b) data in more useful or intelligible form (Ans)

(c) alphanumeric data

(d) program


48. A computer programmer

(a) does all the thinking for a computer (Ans)

(b) can enter input data quickly

(c) can operate all types of computer equipment

(d) can draw only flowchart


49. A character is represented in EBCDIC by:

(a) one bit

(b) four bits

(c) eight bits (Ans)

(d) sixteen bits

(e) None of the above


50. Most of the errors blamed on computers are actually due to

(a) programming errors

(b) hardware fatique

(c) defects in floppy disks

(d) data entry errors (Ans)


51. Which is a secondary memory device ?

(a) CPU

(b) ALU

(c) Floppy disk (Ans)

(d) Mouse

(e) None of the above


52. Which is the most significant difference between a simple desk calculator and computer? Choose from the following (note that some of the following may not even be true).

(a) the computer is an electronic machine while the desk calculator may or may not be electronic

(b) the computer is useful in business applications while the desk calculator is not

(c) the computer can print its results, while the desk calculator can only show it on a display

(d) the computer is controlled by a program stored in its memory while calculator require step-by-step manual control (Ans)

(e) One has to know the method of calculation while using a calculator but a computer user can depend upon the computer to choose the method automatically.


53. A term associated with the comparison of processing speeds of different computer systems is :

(a) EFTS

(b) MPG

(c) MIPS (Ans)

(d) CPS


54. RAM is used as a short memory beacuse it

(a) is volatile (Ans)

(b) is very expensive

(c) has small capacity

(d) is programmable

(e) None of the above


55. General purpose computes are those that can be adopted to countless uses simply by changing its.

(a) keyboard

(b) printer

(c) program (Ans)

(d) display screen

(e) None of the above


56. Which is the computer memory that does not forget?

(a) ROM (Ans)

(b) RAM

(c) PROM

(d) All of the above

(e) None of the above


57. The Senta Clara Valley near Palo Alto, California is popularly known as Silicon Valley of America because

(a) huge deposits of silicon are found there

(b) many silicon chip manufacturing firms are located there (Ans)

(c) Santa Claus visits it every Christmas

(d) it is full of large grain sand


58. Computers are incapable of emotional feelings. However, some people attribute humanlike emotions to imitate objects including computers. What is it called?

(a) anthropogenesis

(b) anthropomorphism (Ans)

(c) anthroolatory

(d) cybernetics


59. According to you, which of the following statements is incorrect?

(a) generally, computers don,t make mistakes

(b) computers eliminate jobs

(c) computers can think (Ans)

(d) maths is necessary to understand computers


60. The most common binary code in use today is the 8 bit ASCII code. What do the letters ASCII stand for?

(a) American Standard Code for International Interchange

(b) American Standard Code for Information Interchange (Ans)

(c) American Standard Code for Intelligence interchange

(d) American Scientific Code for Information Interchange

(e) None of the above

ONGC Placement Paper : ONGC Placement Paper Mechanical engineering 24 October 2012

1 What is the difference between isotropic and anisotropic materials?

Ans If a material exhibits same mechanical properties regardless of loading direction, it is isotropic eg., homogeneous cast materials. Materials lacking this property are anisotropic

2 what are orthotropic materials

It is a special class of anisotropic materials which can be described by giving their properties in three perpendicular direction et wood composites

3 A plain carbon steel has BHN of 180 What are values of Rc, VHN and ultimate strength?

Ans Rc-RHN/10 18,VHN BHN 180

4 What properties need to be considered for applications calling for following requirement:

irigdity

strength for no plastic deformation under static load

wear resistance

reliability and safety

Ans Rigidity- elastic modules and yield strength

Strength for no plastic deformation under static loading-yield point

Wear resistance-Hardness

Reliability and safety-Endurance limit and yield point

5 Explain the effects of alloying chromium and nickel in stainless steel.

Addition of nickel and chromium increases the tensile strength and increase in resistance to corrosion takes place.

6 Mention two types of dislocation,

Dislocation refers to a break in the continuity of the lattice. In edge dislocation, one place of atoms gets squeezed out.In screw dislocation the lattice atoms move from their regular ideal positions.

7 What are the principal constituents of brass?

Principal constituents of brass are copper and zinc

8 what is curie point?

Curie point is te temperature at which ferromagnetic materials can no longer be magnetized by outside forces

9 Specific strength of materials is very high when they are in fiber size but lower when they are in bar form-Why?

Crystal structure has ordered, repeating arrangement of atoms, fibers are liable to maintain this and thus have high specific strength. As size increases, the condition of ordered and repeating arrangements cant be guaranteed because of several types of defects and dislocations and thus the specific strength gets lower

10 what is the percentage of carbon in cast iron?

2.5%

11 Which element is added in steel to increase resistance to corrosion?

Chromium

12 whether individual component material retain their characteristics or not

Yes

13 An elastomer is a polymer when its percentage elongation rate is

Greater than 100%

14 If % elongation of material is more tha 200% it is classed as

Rubber

15 Why is it that the maximum value which the residual stress can reach is the elastic limit of the material?

A stress in excess of elastic limit with no external force to oppose it will relieve itself by plastic deformation until it reaches the value of the yield stress

16 Why fatigue strength decreases as size of a part increase beyond around 10 mm?

Perfection of material conditions is possible at lower sizes and as size increases, it is not possible to attain uniform structure of the material

17 Distinguish between creep and fatigues

Creep is low and progressive deformation of a material with time under a constant stress at high temperature application. Fatigue is the reduced tendency of material to offer resistance to applied stress under repeated or fluctuating loading conditions?

18 While normal carbursing and nitriding surface treatments increase fatigue strength excessive treatment may decrease the fatigue strength Why

Normal carbursing/nitiriding treatments increase volume due to phase transformation at surface and introduce residual compressive surface stress and thus increase the fatigue strength, By excessive treatment the high compressive stresses are introduced but these are balanced by high internal tensile stresses of equal value and the subsurface fatigue cracks may develop in the regions of high tensile stress and lead to early fatigue failures

19 List at least two factors that promote transition form ductile to brittle fracture

Manner of loading and the rate of loading promote transition from ductile to brittle fracture, A machine member may have ductile failure under static loading but may fail in brittle fashion when the load is fluctuating Similarly a material may evidence ductile failure under tensile loading at ordinary testing speed but if load is applied at a high velocity then failure may be brittle

20 Which theories of failure are used for (a) ductile material and (b) brittle materials

For ductile materials theories of failure used are maximum shear stress theory, and maximum energy of distortion theory, while for brittle materials theory of maximum principal stress and maximum strain are used

21 what is stellite?

I t is a non ferrous cast alloy containing cobalt chromium and tungsten

22 Car tyres are usually made of

styrene butadine rubbe

23 What is the structure of pure iron and whether it is soft or hard?

Ferrite and it is soft

24 which elements increase the corrosion resistance of steel?

Chromium and nickel

25 Which rays are produced by cobalt 60 in industrial radiography?

Gamma rays

ONGC Placement Paper : ONGC Placement Paper Electronics and Electrical 15 October 2012

Electrical Engineering Questions and Answers
,
1. A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second.
(a) 100 n
(b) 50 jt
(c) 25 jt
(d) 5 n
Ans: a

2. The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.
(a) 2.5
(b) 5
(c) 10
(d) 15
Ans: c


3. The period of a wave is
(a) the same as frequency
(6) time required to complete one cycle
(c) expressed in amperes
(d) none of the above
Ans: b


4. The form factor is the ratio of
(a) peak value to r.m.s. value
(6) r.m.s. value to average value
(c) average value to r.m.s. value
(d) none of the above
Ans: b


5. The period of a sine wave is _____ seconds.
Its frequency is
(a) 20 Hz
(b) 30 Hz
(c) 40 Hz
(d) 50 Hz
Ans: d


6. A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to
(a) average voltage
(b) r.m.s. voltage
(c) peak voltage
(d) none of the above
Ans: b

7. If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is
(a) a sinusoid of the same frequency
(b) a sinusoid of half the original frequency
(c) a sinusoid of double the frequency
(d) not a sinusoid
Ans: a

8. The peak value of a sine wave is 200 V. Its average value is
(a) 127.4 V
(b) 141.4 V
(c) 282.8 V
(d)200V
Ans: a

9. If two sine waves of the same frequency have a phase difference of JT radians, then
(a) both will reach their minimum values at the same instant
(b) both will reach their maximum values at the same instant
(c) when one wave reaches its maximum value, the other will reach its minimum value
(d) none of the above
Ans: c

10. The voltage of domestic supply is 220V. This figure represents
(a) mean value
(b) r.m.s. value
(c) peak value
(d) average value
Ans: a

11. Two waves of the same frequency have opposite phase when the phase angle between them is
(a) 360°
(b) 180°
(c) 90°
(d) 0°
Ans: b

12. The power consumed in a circuit element will be least when the phase difference between the current and
voltage is
(a) 180"
(b) 90°
(c) 60°
(d) 0°
Ans: b

13. The r.m.s. value and mean value is the same in the case of
(a) triangular wave
(6) sine wave
(c) square wave
(d) half wave rectified sine wave
Ans: c

14. For the same peak value which of the following wave will ,have the highest r.m.s. value ?
(a) square wave
(b) half wave rectified sine wave
(c) triangular wave
(d) sine wave
Ans: a

15. For the same peak value, which of the following wave has the least mean value ?
(a) half wave rectified sine wave
(b) triangular wave
(c) sine wave
(d) square wave
Ans: a

16. For a sine wave with peak value Imax the r.m.s. value is
(a) 0.5 Imax
(b) 0.707
(c) 0.9
(d) 1.414 Lmax
Ans: b

17. Form Factor is the ratio of
(a) average value/r.m.s. value
(b) average value/peak value
(e) r.m.s. value/average value
(d) r.m.s. value/peak value
Ans: c

18. Form factor for a sine wave is
(a) 1.414
(b) 0.707
(c) 1.11
(d) 0.637
Ans: c

19. For a sine wave with peak value Emax______8.30. the average value is
(a) 0.636 Emax
(b) 0.707 Emax
(c) 0.434 EWc
(d) lAUEmax
Ans: a

20. For a frequency of 200 Hz, the time period will be
(a) 0.05 s
(b) 0.005 s
(c) 0.0005 s
(d) 0.5 s
Ans: b

21. The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that
(a) both waves must have same frequency
(b) both waves must have identical peak values
(c) both waves must have zero value at the same time
(d) none of the above
Ans: a

22. The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of______degrees.
(a) 90
(b) 60
(c) 45
(d) 30
Ans: c

23. Capacitive reactance is more when
(a) capacitance is less and frequency of supply is less
(b) capacitance is less and frequency of supply is more
(c) capacitance is more and frequency of supply is less
(d) capacitance is more and frequency of supply is more
Ans: a

24. In a series resonant circuit, the impedance of the circuit is
(a) minimum
(b) maximum
(c) zero
(d) none of the above
Ans: a

25. Power factor of an electrical circuit is equal to
(a) R/Z
(b) cosine of phase angle difference between current and voltage
(c) kW/kVA
(d) ratio of useful current to total current Iw/I
(e) all above
Ans: e

26. The best place to install a capacitor is
(a) very near to inductive load
(b) across the terminals of the inductive load
(c) far away from the inductive load
(d) any where
Ans: b

27. Poor power factor
(a) reduces load handling capability of electrical system
(b) results in more power losses in the electrical system
(c) overloads alternators, transformers and distribution lines
(d) results in more voltage drop in the line
(e) results in all above
Ans: e

28. Capacitors for power factor correction are rated in
(a) kW
(b) kVA
(c) kV
(d) kVAR
Ans: d

29. In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value
(a) will change the maximum value of current at resonance
(6) will change the resonance frequency
(c) will change the impedance at resonance frequency
(d) will increase the selectivity of the circuit
Ans: d

30. Pure inductive circuit
(a) consumes some power on average
(b) does not take power at all from a line
(c) takes power from the line during some part of the cycle and then returns back to it during other part of the cycle
(d) none of the above
Ans: c

31. Inductance affects the direct current flow
(a) only at the time of turning off
(b) only at the time of turning on
(c) at the time of turning on and off
(d) at all the time of operation
Ans: c

32. Inductance of a coil Varies
(a) directly as the cross-sectional area of magnetic core
(b) directly as square of number of turns
(c) directly as the permeability of the core
(d) inversely as the length of the iron path
(e) as (a) to (d)
Ans: e

33. All the rules and laws of D.C. circuit also apply to A.C. circuit containing
(a) capacitance only
(b) inductance only
(c) resistance only
(d) all above
Ans: c

34. Time constant of an inductive circuit
(a) increases with increase of inductance and decrease of resistance
(b) increases with the increase of inductance and the increase of resistance
(c) increases with decrease of inductance and decrease of resistance
(d) increases with decrease of inductance and increase of resistance
Ans: a

35. Power factor of an inductive circuit is usually improved by connecting capacitor to it in
(a) parallel
(b) series
(c) either (a) or (b)
(d) none of the above
Ans: a

36. In a highly capacitive circuit the
(a) apparent power is equal to the actual power
(b) reactive power is more than the apparent power
(c) reactive power is more than the actual powetf
(d) actual power is more than its reactive power
Ans: c

37. Power factor of the following circuit will be zero
(a) resistance
(b) inductance
(c) capacitance
(d) both (b) and (c)
Ans: d

38. Power factor of the following circuit will be unity
(a) inductance
(b) capacitance
(c) resistance
(d) both (a) and (b)
Ans: c

39. Power factor of the system is kept high
(a) to reduce line losses
(b) to maximise the utilization of the capacities of generators, lines and transformers
(c) to reduce voltage regulation of the line
(d) due to all above reasons
Ans: d

40. The time constant of the capacitance circuit is defined as the time during which voltage
(a) falls to 36.8% of its final steady value
(b) rises to 38.6% of its final steady value
(c) rises to 63.2% of its final steady value
(d) none of the above
Ans: c

41. In a loss-free R-L-C circuit the transient current is
(a) oscillating
(b) square wave
(c) sinusoidal
(d) non-oscillating
Ans: c

42. The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces
(a) the more heat than produced by A.C. when flowing through the same circuit
(b) the same heat as produced by A.C. when flowing through the same circuit
(c) the less heat than produced by A.C. flowing through the same circuit
(d) none of the above
Ans: b

43. The square waveform of current has following relation between r.m.s. value and average value.
(a) r.m.s. value is equal to average value
(b) r.m.s. value of current is greater than average value
(c) r.m.s. value of current is less than average value
(d) none of the above
Ans: a

44. The double energy transient occur in the
(a) purely inductive circuit
(b) R-L circuit
(c) R-C circuit
(d) R-L-C circuit
Ans: d

45. The transient currents are associated with the
(a) changes in the stored energy in the inductors and capacitors
(b) impedance of the circuit
(c) applied voltage to the circuit
(d) resistance of the circuit
Ans: a

46. The power factor at resonance in R-L- C parallel circuit is
(a) zero
(b) 0.08 lagging
(c) 0.8 leading
(d) unity
Ans: d

47. In the case of an unsymmetrical alternating current the average value must always be taken over
(a) unsymmetrical part of the wave form
(b) the quarter cycle
(c) the half cycle
(d) the whole cycle
Ans: d

48. In a pure resistive circuit
(a) current lags behind the voltage by 90°
(b) current leads the voltage by 90°
(c) current can lead or lag the voltage by 90°
(d) current is in phase with the voltage
Ans: d

49. In a pure inductive circuit
(a) the current is in phase with the voltage
(b) the current lags behind the voltage by 90°
(c) the current leads the voltage by 90°
(d) the current can lead or lag by 90°
Ans: b

50. In a circuit containing R, L and C, power loss can take place in
(a) C only
(b) L only
(c) R only
(d) all above
Ans: c

51. Inductance of coil
(a) is unaffected by the supply frequency
(b) decreases with the increase in supply frequency
(c) increases with the increase in supply frequency
(d) becomes zero with the increase in supply frequency
Ans: c

52. In any A.C. circuit always
(a) apparent power is more than actual power
(b) reactive power is more than apparent power
(c) actual power is more than reactive power
(d) reactive power is more than actual power
Ans: a

53. Which of the following circuit component opposes the change in the circuit voltage ?
(a) Inductance
(b) Capacitance
(c) Conductance
(d) Resistance
Ans:

54. In a purely inductive circuit
(a) actual power is zero
(b) reactive power is zero
(c) apparent power is zero
(d) none of above is zero
Ans: a

55. Power factor of electric bulb is
(a) zero
(b) lagging
(c) leading
(d) unity
Ans: d

56. Pure inductive circuit takes power from the A.C. line when
(a) applied voltage decreases but cur¬rent increases
(b) applied voltage increases but cur¬rent decreases
(c) both applied voltage and current increase
(d) both applied voltage and current decrease
Ans: a

57. Time constant of a circuit is the time in seconds taken after the application of voltage to each
(a) 25% of maximum value
(b) 50% of maximum value
(c) 63% of maximum value
(d) 90% of the maximum value
Ans: c

58. Time constant of an inductive circuit
(a) increases with increase of inductance and decrease of resistance
(b) increases with the increase of inductance and the increase of resistance
(c) increases with the decrease of inductance and decrease of resistance
(d) increases with decrease of inductance and increase of resistance
Ans: a

59. Time constant of a capacitive circuit
(a) increases with the decrease of capacitance and decrease of resistance
(b) increases with the decrease of capacitance and increase of resis¬tance
(c) increases with the increase of capacitance and decrease of resis¬tance
(d) increase with increase of capacitance and increase of resis¬tance
Ans: d

60. Magnitude of current at resonance in R-L-C circuit
(a) depends upon the magnitude of R
(b) depends upon the magnitude of L
(c) depends upon the magnitude of C
(d) depends upon the magnitude of R, LandC
Ans: a

61. In a R-L-C circuit
(a) power is consumed in resistance and is equal to I R
(b) exchange of power takes place between inductor and supply line
(c) exchange of power takes place between capacitor and supply line
(d) exchange of power does not take place between resistance and the supply line
(e) all above are correct
Ans: e

62. In R-L-C series resonant circuit magnitude of resonance frequency can be changed by changing the value of
(a) R only
(b) L only
(c) C only
(d) L or C
(e) R,L or C
Ans: d

63. In a series L-C circuit at the resonant frequency the
(a) current is maximum
(b) current is minimum
(c) impedance is maximum
(d) voltage across C is minimum
Ans: a

64. The time constant of a series R-C circuit is given by
(a) R/C
(b) RC2
(c) RC
(d) R2C
Ans: c

65. If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be
(a) 0.001 s
(b) 0.1 s
(c) 10 s
(d) 100 s
Ans: b

66. Which of the following coil will have large resonant frequency ?
(a) A coil with large resistance
(b) A coil with low resistance
(c) A coil with large distributed capacitance
(d) A coil with low distributed capacitance
Ans: c

67. If a sinusoidal wave has frequency of 50 Hz with 30 A r.m.s. current which of the following equation represents this wave ?
(a) 42.42 sin 3141
(b) 60 sin 25 t
(c) 30 sin 50 t
(d) 84.84 sin 25 t
Ans: a

68. The safest value of current the human body can carry for more than 3 second is
(a) 4 mA
(b) 9 mA
(c) 15 mA
(d) 25 mA
Ans: b

69. A pure inductance connected across 250 V, 50 Hz supply consumes 100 W.
This consumption can be attributed to
(a) the big size of the inductor
(b) the reactance of the inductor
(c) the current flowing in the inductor
(d) the statement given is false
Ans: d

70. The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA
The power drawn by the circuit is
(a) 12 kW
(b) 22 kW
(c) 32 kW
(d) 64 kW
Ans: c

71. The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of
(a) iron loss in core
(b) skin effect
(c) increase in temperature
(d) capacitive effect between adjacent coil turns
Ans: a

72. In an AC. circuit, a low value of kVAR compared with kW indicates
(a) low efficiency
(b) high power factor
(c) unity power factor
(d) maximum load current
Ans: b

73. In AC. circuits, laminated iron is invariably used in order to
(a) reduce eddy current loss
(b) increase heat radiation
(c) make assembly cheap and easier
(d) reduce circuit permeability
Ans: a

74. The ratio of active power to apparent power is known as factor.
(a) demand
(b) load
(c) power
(d) form
Ans: c

75. All definitions of power factor of a series R-L-C circuit are correct except
(a) ratio of net reactance and impedance
(b) ratio of kW and kVA
(c) ratio of J and Z
(d) ratio of W and VA
Ans: a

76. The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is
(a) 4 kVAR
(b) 6 kVAR
(c) 8 kVAR
(d) 16 kVAR
Ans: b

77. What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value ?
(a) 0°
(b) 45°
(c) 90°
(d) 180°
Ans: c

78. The purpose of a parallel circuit resonance is to magnify
(a) current
(b) voltage
(c) power
(d) frequency
Ans: b

79. In an A.C. circuit power is dissipated in
(a) resistance only
(b) inductance only
(c) capacitance only
(d) none of the above
Ans: a

80. In a parallel R-C circuit, the current always______the applied voltage
(a) lags
(b) leads
(c) remains in phase with
(d) none of the above
Ans: b

81. At very low frequencies a series R-C circuit behaves as almost purely
(a) resistive
(b) inductive
(c) capacitive
(d) none of the above
Ans: c

82. Skin effect occurs when a conductor carries current at _____ frequencies.
(a) very low
(b) low
(c) medium
(d) high
Ans: d

83. At ______ frequencies the parallel R-L circuit behaves as purely resistive.
(a) low
(b) very low
(c) high
(d) very high
Ans: d

84. In a sine wave the slope is constant
(a) between 0° and 90°
(b) between 90° and 180°
(c) between 180° and 270°
(d) no where
Ans: d

85. The power is measured in terms of decibles in case of
(a) electronic equipment
(b) transformers
(c) current transformers
(d) auto transformers
Ans: a

86. Capacitive susceptance is a measure of
(a) reactive power in a circuit
(b) the extent of neutralisation of reactive power in a circuit
(c) a purely capacitive circuit,s ability to pass current
(d) a purely capacitive circuit,s ability to resist the flow of current
Ans: c

87. Which of the following statements pertains to resistors only ?
(a) can dissipate considerable amount of power
(6) can act as energy storage devices
(c) connecting them in parallel in¬creases the total value
(d) oppose sudden changes in voltage
Ans: a

88. Which of the following refers to a parallel circuit ?
(a) The current through each element is same
(b) The voltage across element is in proportion to it,s resistance value
(c) The equivalent resistance is greater than any one of the resistors
(d) The current through any one element is less than the source current
Ans: d

89. Aphasoris
(a) a line which represents the mag¬nitude and phase of an alternating quantity
(b) a line representing the magnitude and direction of an alternating quantity
(c) a coloured tag or band for distinction between different phases of a 3-phase supply
(d) an instrument used for measuring phases of an unbalanced 3-phase load
Ans: a

89. A parallel AC. circuit in resonance will
(a) have a high voltage developed across each inductive and capacitive section
(b) have a high impedance
(c) act like a resistor of low value
(d) have current in each section equal to the line current
Ans: b

90. Wire-wound resistors are unsuitable for use at high frequencies because they
(a) create more electrical noise
(b) are likely to melt under excessive eddy current heat
(c) consume more power
(d) exhibit unwanted inductive and capacitive effects
Ans: d

91. The inductance of a coil can be increased by
(a) increasing core length
(b) decreasing the number of turns
(c) decreasing the diameter of the former
(d) choosing core material having high relative permeability
Ans: d

92. In a three-phase supply floating neutral is undesirable because it way give rise to
(a) high voltage across the load
(b) low voltage across the load
(c) unequal line voltages across the load
Ans: c

93. Which of the following waves has the highest value of peak factor ?
(a) Square wave
(b) Sine wave
(c) Half wave rectified sine wave
(d) Triangular wave
Ans: c

94. The frequency of domestic power supply in India is
(a) 200 Hz
(b) 100 Hz
(c) 60 Hz
(d) 50 Hz
Ans: d

95. The r.m.s. value of half wave rectified sine wave is 200 V. The r.m.s. value of full wave rectified AC. will be
(a) 282.8 V
(b) 141.4 V
(c) 111 V
(d) 100 V
Ans: a

96. The r.m.s. value of pure cosine function is
(a) 0.5 of peak value
(b) 0.707 of peak value
(c) same as peak value
(d) zero
Ans: b

97. Ohm is unit of all of the following except
(a) inductive reactance
(b) capacitive reactance
(c) resistance
(d) capacitance
Ans: d

98. The series ;nd parallel resonance on L-C circui, differs in that
(a) series resistance needs a low-resistance ource for sharp rise in current
(b) series resonance needs a high-resistance source for sharp increase in current
(c) parallel resonance needs a low-resistance source for a sharp in¬crease in impedance
(d) parallel resonance needs a low-resistance source for a sharp rise in line current
Ans: a

99. The phasors for which of the following pair are 180° out of phase for VL, VC and VR?
(a) Vc and VR
(b) VL and VR
(c) Vc and VL
(d) none of the above
Ans: c

100. The frequency of an alternating current is
(a) the speed with which the alternator runs
(b) the number of cycles generated in one minute
(c) the number of waves passing through a point in one second
(d) the number of electrons passing through a point in one second
Ans: c

101. A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to
(a) the capacitive reactance in ohms
(b) the current flowing in capacitor
(c) the size of the capacitor being quite big
(d) the statement is incorrect
Ans: d

102. The power factor of a D.C. circuit is always
(a) less than unity
(b) unity
(c) greater than unity
(d) zero
Ans: b

103. The product of apparent power and cosine of the phase angle between circuit voltage and current is
(a) true power
(b) reactive power
(c) volt-amperes
(d) instantaneous power
Ans: a

104. The equation of 50 Hz current sine wave having r.m.s. value of 60 A is
(a) 60 sin 25 t
(b) 60 sin 50 t
(c) 84.84 sin 3141
(d) 42.42 sin 314 t
Ans: c

105. An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms,
(a) the current through the resistance is more
(b) the current through the resistance is less
(c) both resistance and inductance carry equal currents
(d) none of the above
Ans: c

106. In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will
(a) be reduced by half
(b) be doubled
(c) be four times as high
(d) be reduced to one fourth
Ans: b

107. In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will
(a) be reduced by half
(b) be doubled
(c) be four times at high
(d) be reduced to one fourth
Ans: a

108. When an alternating current passes through an ohmic resistance the electrical power converted into heat is
(a) apparent power
(b) true power
(c) reactive power
(d) none of the above
Ans: b

109. In each of the three coils of a three phase generator, an alternating voltage having an r.m.s. value of 220 V is induced. Which of the following values is indicated by the voltmeters ?
(a) 220 V
(b) 220V3V
(c) 220/V3 V
(d) none of the above
Ans: a


110. Laminations of core are generally made of
(a) case iron
(b) carbon
(c) silicon steel
(d) stainless steel

1Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
(a) 270 V
(b) 267.5 V
(c) 265 V
(d) 257.4 V
Ans: b

Ans: c
2. Which of the following could be lamina-proximately the thickness of lamina-tions of a D.C. machine ?
(a) 0.005 mm
(b) 0.05 mm
(c) 0.5 m
(d) 5 m
Ans: c


3. The armature of D.C. generator is laminated to
(a) reduce the bulk
(b) provide the bulk
(c) insulate the core
(d) reduce eddy current loss
Ans: d


4. The resistance of armature winding depends on
(a) length of conductor
(b) cross-sectional area of the conductor
(c) number of conductors
(d) all of the above
Ans: d


5. The field coils of D.C. generator are usually made of
(a) mica
(b) copper
(c) cast iron
(d) carbon
Ans: b


6. The commutator segments are connected to the armature conductors by means of
(a) copper lugs
(b) resistance wires
(c) insulation pads
(d) brazing
Ans: a

7. In a commutator
(a) copper is harder than mica
(b) mica and copper are equally hard
(c) mica is harder than copper
(d) none of the above
Ans: c

8. In D.C. generators the pole shoes are fastened to the pole core by
(a) rivets
(b) counter sunk screws
(c) brazing
(d) welding
Ans: b

9. According to Fleming,s right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of
(a) motion of conductor
(b) lines of force
(c) either of the above
(d) none of the above
Ans: b

10. Fleming,s right-hand rule regarding direction of induced e.m.f., correlates
(a) magnetic flux, direction of current flow and resultant force
(b) magnetic flux, direction of motion and the direction of e.m.f. induced
(c) magnetic field strength, induced voltage and current
(d) magnetic flux, direction of force and direction of motion of conductor
Ans: b

11. While applying Fleming,s right-hand rule to And the direction of induced e.m.f., the thumb points towards
(a) direction of induced e.m.f.
(b) direction of flux
(c) direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
(d) direction of motion of conductor, if forefinger points along the lines of flux
Ans: d

12. The bearings used to support the rotor shafts are generally
(a) ball bearings
(b) bush bearings
(c) magnetic bearmgs
(d) needle bearings
Ans: a

13. In D.C. generators, the cause of rapid brush wear may be
(a) severe sparking
(b) rough commutator surface
(c) imperfect contact
(d) any of the above
Ans: d

14. In lap winding, the number of brushes is always
(a) double the number of poles
(b) same as the number of poles
(c) half the number of poles
(d) two
Ans: b

15. For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f. ?
(a) Lap winding
(b) Wave winding
(c) Either of (a) and (b) above
(d) Depends on other features of design
Ans: b

16. In a four-pole D.C. machine
(a) all the four poles are north poles
(b) alternate poles are north and south
(c) all the four poles are south poles
(d) two north poles follow two south poles
Ans: b

17. Copper brushes in D.C. machine are used
(a) where low voltage and high currents are involved
(b) where high voltage and small cur-rents are involved
(c) in both of the above cases
(d) in none of the above cases
Ans: a

18. A separately excited generator as compared to a self-excited generator
(a) is amenable to better voltage con-trol
(b) is more stable
(c) has exciting current independent of load current
(d) has all above features
Ans: d

19. In case of D.C. machines, mechanical losses are primary function of
(a) current
(b) voltage
(c) speed
(d) none of above
Ans: c

20. Iron losses in a D.C. machine are independent of variations in
(a) speed
(b) load
(c) voltage
(d) speed and voltage
Ans: b

21. In D.C. generators, current to the external circuit from armature is given through
(a) commutator
(b) solid connection
(c) slip rings
(d) none of above
Ans: a

23. Brushes of D.C. machines are made of
(a) carbon
(b) soft copper
(c) hard copper
(d) all of above
Ans: a

24. If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
(a)Blv
(b)Blv2
(c)Bl2v
(d)Bl2v2
Ans: a

25. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
(a) 4
(b) 8
(c) 16
(d) 32
Ans: b

26. The material for commutator brushes is generally
(a) mica
(b) copper
(c) cast iron
(d) carbon
Ans: d

27. The insulating material used between the commutator segments is normally
(a) graphite
(b) paper
(c) mica
(d) insulating varnish
Ans: c

28. In D.C. generators, the brushes on commutator remain in contact with conductors which
(a) lie under south pole
(b) lie under north pole
(c) lie under interpolar region
(d) are farthest from the poles
Ans: c

29. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
(a) demagnetisation only
(b) cross magnetisation as well as magnetisation
(c) crossmagnetisation as well as demagnetising
(d) cross magnetisation only
Ans: c

30. Armature reaction of an unsaturated D.C. machine is
(a) crossmagnetising
(b) demagnetising
(c) magnetising
(d) none of above
Ans: a

31. D.C. generators are connected to the busbars or disconnected from them only under the floating condition
(a) to avoid sudden loading of the primemover
(b) to avoid mechanicaljerk to the shaft
(c) to avoid burning of switch contacts
(d) all above
Ans: d

32. Eddy currents are induced in the pole shoes of a D.C. machine due to
(a) oscillating magnetic field
(b) pulsating magnetic flux
(c) relative rotation between field and armature
(d) all above
Ans: c

33. In a D.C. machine, short-circuited field coil will result in
(a) odour of barning insulation
(b) unbalanced magnetic pull producing vibrations
(c) reduction of generated voltage for which excitation has to be increased to maintain the voltage
(d) all above
Ans:

34. Equilizer rings are required in case armature is
(a) wave wound
(b) lap wound
(c) delta wound
(d) duplex wound
Ans: b

35. Welding generator will have
(a) lap winding
(b) wave winding
(c) delta winding
(d) duplex wave winding
Ans: a

36. In case of D.C. machine winding, number of commutator segments is equal to
(a) number of armature coils
(b) number of armature coil sides
(c) number of armature conductors
(d) number of armature turns
Ans: a

37. For a D.C. machines laboratory following type of D.C. supply will be suitable
(a) rotary converter
(b) mercury are rectifier
(c) induction motor D.C. generator set
(d) synchronous motor D.C. generator set
Ans: c

38. The function of pole shoes in the case of D.C. machine is
(a) to reduce the reluctance of the magnetic path
(b) to spread out the flux to achieve uniform flux density
(c) to support the field coil
(d) to discharge all the above functions
Ans: d

39. In the case of lap winding resultant pitch is
(a) multiplication of front and back pitches
(b) division of front pitch by back pitch
(c) sum of front and back pitches
(d) difference of front and back pitches
Ans: d

40. A D.C. welding generator has
(a) lap winding
(b) wave moving
(c) duplex winding
(d) any of the above
Ans: a

41. Which of the following statement about D.C. generators is false ?
(a) Compensating winding in a D.C. machine helps in commutation
(b) In a D. C. generator interpoles winding is connected in series with the armature winding
(c) Back pitch and front pitch are both odd and approximately equal to the pole pitch
(d) Equilizing bus bars are used with parallel running of D.C. shunt generators
Ans: d

42. The demagnetising component of armature reaction in a D.C. generator
(a) reduces generator e.m.f.
(b) increases armature speed
(c) reduces interpoles flux density
(d) results in sparking trouble
Ans: a

43. Magnetic field in a D.C. generator is produced by
(a) electromagnets
(b) permanent magnets
(c) both (a) and (b)
(d) none of the above
Ans: a

44. The number of brushes in a commutator depends on
(a) speed of armature
(b) type of winding
(c) voltage
(d) amount of current to be collected
Ans: d

45. Compensating windings are used in D.C. generators
(a) mainly to reduce the eddy currents by providing local short-circuits
(b) to provide path for the circulation of cooling air
(c) to neutralise the cross-magnetising effect of the armature reaction
(d) none of the above
Ans: c

46. Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?
(a) Dummy coils
(b) Commutator
(c) Eye bolt
(d) Equilizer rings
Ans: b

47. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
(a) using conductor of annealed copper
(b) using commutator with large number of segments
(c) using carbon brushes of superior quality
(d) using equiliser rings
Ans: c

48. In D.C. generators, lap winding is used for
(a) high voltage, high current
(b) low voltage, high current
(c) high voltage, low current
(d) low voltage, low current
Ans: b

49. Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be
(a) 2 : 3
(b) 3 : 1
(c) 3 : 2
(d) 1 : 3
Ans: b

50. The voltage drop for which of the following types of brush can be expected to be least ?
(a) Graphite brushes
(b) Carbon brushes
(c) Metal graphite brushes
(d) None of the above
Ans: c

51. The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be
(a) E/2
(b) 2E
(c) slightly less than E
(d) E
Ans: b

52. In a D.C. generator the actual flux distribution depends upon
(a) size of air gap
(b) shape of the pole shoe
(c) clearance between tips of the ad¬jacent pole shoes
(d) all of the above
Ans:

53. The armature core of a D.C. generator is usually made of
(a) silicon steel
(b) copper
(c) non-ferrous material
(d) cast-iron
Ans: a

9.63. Satisfactory commutation of D.C. machines requires
(a) brushes should be of proper grade and size
(b) brushes should smoothly run in the holders
(c) smooth, concentric commutator properly undercut
(d) all of the above
Ans: d

54. Open circuited armature coil of a D.C. machine is
(a) identified by the scarring of the commutator segment to which open circuited coil is connected
(b) indicated by a spark completely around the commutator
(c) both (a) and (b)
(d) none of the above
Ans: c

55. In a D.C. machine, fractional pitch winding is used
(a) to increase the generated voltage
(b) to reduce sparking
(c) to save the copper because of shorter end connections
(d) due to (b) and (c) above
Ans:

56. For the parallel operation of two or more D.C. compound generators, we should ensure that
(a) voltage of the incoming generator should be same as that of bus bar
(b) polarity of incoming generator should be same as that of bus bar
(c) all the series fields should be run in parallel by means of equilizer connection
(d) series fields of all generators should be either on positive side or negative side of the armature
(e) all conditions mentioned above should be satisfied
Ans: d

57. D.C. series generator is used
(a) to supply traction load
(b) to supply industrial load at constant voltage
(c) voltage at the toad end of the feeder
(d) for none of the above purpose
Ans: c

58. Following D.C. generator will be in a position to build up without any residual magnetism in the poles
(a) series generator
(b) shunt generator
(c) compound generator
(d) self-excited generator
Ans: d

59. Interpole flux should be sufficient to
(a) neutralise the commutating self induced e.m.f.
(b) neutralise the armature reaction flux
(c) neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil
(d) perform none of the above functions
Ans: c

60. D.C. generator generally preferred for charging automobile batteries is
(a) series generator
(b) shunt generator
(c) long shunt compound generator
(d) any of,the above
Ans: c

61. In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when
(a) r.p.m. is more than 300
(b) r.p.m. is less than 300
(c) number of poles is 4
(d) number of poles is 2
Ans: d

62. Permeance is the reciprocal of
(a) flux density
(b) reluctance
(c) ampere-turns
(d) resistance
Ans: b

63. In D.C. generators the polarity of the interpoles
(a) is the same as that of the main pole ahead
(b) is the same as that of the immediately preceding pole
(c) is opposite to that of the main pole ahead
(d) is neutral as these poles do not play part in generating e.m.f.
Ans: a

64. The e.m.f. generated in a D.C. generator is directly proportional to
(a) flux/pole
(b) speed of armature
(c) number of poles
(d) all of the above
Ans: b

65. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when
(a) there is no load on|he generator
(b) the generator runs on full load
(c) the generator runs on overload
(d) the generator runs on designed speed
Ans: a

66. In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except
(a) interpoles
(b) dummy coils
(c) compensating winding
(d) shifting of axis of brushes
Ans: b

67. In D.C. generators on no-load, the air gap flux distribution in space is
(a) sinusoidal
(b) triangular
(c) pulsating
(d) flat topped
Ans: d

68. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly
(a) 150 V
(b) 175 V
(c) 240 V
(d) 290 V
Ans: c

69. The purpose of providing dummy coils in a generator is
(a) to reduce eddy current losses
(b) to enhance flux density
(c) to amplify voltage
(d) to provide mechanical balance for the rotor
Ans: d

70. In a shunt generator the voltage build up is generally restricted by
(a) speed limitation
(b) armature heating
(c) insulation restrictions
(d) saturation of iron
Ans:

71. If a D.C. generator fails to build up the probable cause could not be
(a) imperfect brush contact
(b) field resistance less than the critical resistance
(c) no residual magnetism in the generator
(d) faulty shunt connections tending to reduce the residual magnetism
Ans: b

72. Flashing the field of D.C. generator means
(a) neutralising residual magnetism
(b) creating residual magnetism by a D.C. source
(c) making the magnetic losses of forces parallel
(d) increasing flux density by adding extra turns of windings on poles
Ans: b

73. The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be
(a) 640 V
(b) 620 V
(c) 600 V
(d) 580 V
Ans: d

74. In a D.C. generator the critical resistance refers to the resistance of
(a) brushes
(b) field
(c) armature
(d) load
Ans: b

75. To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them
(a) just ahead of magnetic neutral axis
(b) in magnetic neutral axis
(c) just behind the magnetic neutral axis
Ans: a

76. Armature coil is short circuited by brushes when it lies
(a) along neutral axis
(b) along field axis
(c) in any of the above positions
(d) in none of the above positions
Ans: a

77. A cumulatively compounded long shunt generator when operating as a motor would be
(a) cumulatively compounded long shunt
(b) differentially compounded long shunt
(c) cumulatively compounded short shunt
(d) differentially compounded short shunt
Ans: b

78. To avoid formation of grooves in the commutator of a D.C. machine
(a) the brushes of opposite polarity should track each other
(b) the brushes of same polarity should track each other
(c) brush position has no effect on the commutator grooving
Ans: a

79. The following constitute short-circuit in the armature winding.
(a) Insulation failure between two com-mutator bars
(6) Insulation failure between two turns of a coil
(c) Two of more turns of the same coil getting grounded
(d) All of the above
Ans: d

80. The rapid wear of brushes takes place due to
(a) abrasion from dust
(b) excessive spring pressure
(c) rough commutator bars
(d) high mica insulation between com-mutation bars
(e) all of the above factors
Ans: e

81. Number of tappings for each equilizer ring is equal to
(a) number of pole pairs
(b) number of poles
(c) number of parallel paths
(d) number of commutator segments
Ans: a

82. A D.C. generator can be considered as
(a) rectifier
(b) primemover
(c) rotating amplifier
(d) power pump
Ans: c

83. In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilised is called
(a) rotor
(b) stator
(c) field
(d) armature
Ans: d

84. In a D.C. machine stray loss is the sum of
(a) total copper loss and mechanical loss
(b) armature copper loss and iron loss
(c) shunt field copper loss and mechanical loss
(d) iron loss and mechanical loss
Ans: d

85. Lap winding is composed of
(a) any even number of conductors
(b) any odd number of conductors
(c) that even number which is exact multiple of poles + 2
(d) that even number which is exact multiple of poles
Ans: a

86. In a D.C. generator in case the resistance of the field winding is increased, then output voltage will
(a) increase
(b) decrease
(c) remain unaffected
(d) fluctuate heavily
Ans: b

87. An exciter for a turbo generator is a
(a) separately excited generator
(b) shunt generator
(c) series generator
(d) compound generator
Ans: b

88. In case of a flat compounded generator
(a) voltage generated is less than the rated voltage
(b) generated voltage is proportional to the load on the generator
(c) voltage remains constant irrespec¬tive of the load
(d) speed varies in proportion to the load on the generator
Ans: c

89. Which of the following generator will have negligible terminal voltage while running on no-load ?
(a) Series generator
(b) Shunt generator
(c) Compound generator
(d) Separately excited generator
Ans: a

90. Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?
(a) Series generator
(b) Shunt generator
(c) Compound generator
(d) None of the above
Ans: d

91. In over compounded generator, full load terminal voltage is
(a) almost zero
(b) less than noload terminal voltage
(c) more than noload terminal voltage
(d) equal to no-load terminal voltage
Ans: c

92. In a level compounded D.C. generator, full load terminal voltage is
(a) negligibly low
(b) equal to no-load terminal voltage
(c) more than no-load terminal voltage
(d) less than no-load terminal voltage
Ans: b

93. The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except
(a) armature reaction
(b) armature resistance drop
(c) field weakening due to armature reaction and armature
(d) commutation
Ans: d

94. In a D.C. generator
(a) external resistance = internal char-acteristic - armature reaction
(b) internal characteristic = magnetisation characteristic - ohmic drop
(c) external characteristic = magnetisation characteristic - ohmic drop - armature reaction
(d) magnetisation characteristic = external characteristic
Ans: c

95. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave
(a) will be zero
(b) will be of 5 Hz
(c) willbeof5xiVHz
(d) will be of v Hz 5
Ans: b

96. A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be
(a) zero
(b) about 2 V
(c) about 50 V
(d) 220 V
Ans: b

97. In a separately excited generator supplying rated load the armature reaction ,
(a) is always present
(b) is always absent
(c) may be sometimes present
(d) none of the above
Ans: a

98. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
(a) zero
(b) small
(c) the same as rated voltage
(d) high
Ans: a

99. Armature reaction in a generator results in
(a) demagnetisation of leading pole tip and magnetisation of trailing pole tip
(b) demagnetisation of trailing pole tip and magnetisation of leading pole tip
(c) damagnetising the centre of all poles
(d) magnetising the centre of all poles
Ans: a

100. Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure.
(a) Series field
(b) Compensating field
(c) Inter pole field
(d) Shunt field
Ans: d

101. Wave winding is composed of
(a) any even number of conductors
(b) any odd number of conductors
(c) that even number which is exact multiple of poles + 2
(d) that even number which is exact multiple of poles
Ans: c

102. The critical resistance of the D.C. generator is the resistance of
(a) field
(b) brushes
(c) armature
(d) load
Ans: a

103. When two D.C. series generators are running in parallel, an equilizer bar is used
(a) to increase the speed and hence generated e.m.f.
(b) to increase the series flux
(c) so that two similar machines will pass approximately equal currents to the load
(d) to reduce the combined effect of ar-mature reaction of both machines
Ans: c

104. Which of the following generating machine will offer constant voltage on all loads ?
(a) Self-excited generator
(b) Separately excited generator
(c) Level compounded generator .
(d) All of the above
Ans: c

105. Which of the following generators will be preferred if they are required to be run in parallel ?
(a) Shunt generators
(b) Series generators
(c) Compound generators
(d) None of the above
Ans: a

106. Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?
(a) The direction of that generator is reversed
(b) The speed of that generator is increased
(c) The field of that generator is weakened
(d) That generator takes large share of loads
Ans: d

107. A D.C. generator works on the principle of
(a) Lenz,s law
(b) Ohm,s law
(c) Faraday,s law of electromagnetic induction
(d) none of the above
Ans: c

108. A series generator can self-excite
(a) only if the load current is zero
(b) only if the load current is not zero
(c) irrespective of the value of load current
(d) none of the above
Ans: b

109. A shunt generator can self-excite
(a) only if the resistance of the field circuit is less than critical value
(b) only if the resistance of the field circuit is greater than critical value
(c) irrespective of the value of the resis-tance in the field circuit
Ans: a

110. The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be
(a) 150 V
(b) less than 150 V
(c) greater than 150 V
(d) none of the above
Ans: c

111. The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage
(a) will be less than 250 V
(b) will always be 250 V
(c) may be greater or less than 250 V
(d) none of the above
Ans: c

112. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
(a) 270 V
(b) 267.5 V
(c) 265 V
(d) 257.4 V
Ans: b

113. The essential condition for parallel operation of two D.C. generators is that they have ,
(a) same kW rating
(b) the same operation r.p.m.
(c) the same drooping voltage charac-teristics
(d) same percentage regulation
Ans: c

114. When two D.C. generators are running in parallel an equilizer bar is used
(a) to increase the series flux
(b) to increase the generated e.m.f.
(c) to reduce the combined effect of ar-mature reaction of both the machines
(d) so that the two identical machines will pass approximately equal currents to the load
Ans: d

115. With a D.C. generator which of the following regulation is preferred ?
(a) 100% regulation
(b) infinite regulation
(c) 50% regulation
(d) 1% regulation
Ans: d

116. Which generator would you prefer for feeding long D.C. transmission lines ?
(a) Series generator
(b) Shunt generator
(c) Over compound generator
(d) Flat compound generator
Ans: c

117. In a D.C. generator the critical resistance can be increased by
(a) increasing its field resistance
(b) decreasing its field resistance
(c) increasing its speed
(d) decreasing its speed
Ans: c

118. The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is
(a) 2
(b) 4
(c) 6
(d) 8
Ans: b

119. For both lap and wave windings, there are as many commutator bars as the number of
(a) slots
(b) armature conductors
(c) winding elements
(d) poles
Ans: c

120. The series field of a short-shunt D.C. generator is excited by
(a) external current
(b) armature current
(c) shunt current
(d) load current
Ans: d

121. As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately
(a) 40 percent
(b) 25 percent
(c) 10 percent
(d) 5 percent
Ans: d

122. Shunt generators are most suited for stable parallel operation because of their
(a) rising voltage characteristics
(b) identical voltage characteristics
(c) drooping voltage characteristics
(d) linear voltage characteristics
Ans: c

123. The main factor which leads to unstable parallel operation of flat and over compounded generators is
(a) their rising voltage characteristics
(b) unequal number of turns in their series field windings
(c) unequal speed regulation of their prime movers
(d) unequal series field resistances
Ans: a

124. If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
(a) reverse the field connections
(b) increase the field resistance
(c) increase the speed of primemover
(d) check armature insulation resis¬tance
Ans: a

125.The essential condition for parallel operation of two D.C. generators is that they have ,
(a) same kW rating
(b) the same operation r.p.m.
(c) the same drooping voltage charac-teristics
(d) same percentage regulation
Ans: c

ONGC Placement Paper : ONGC Placement Paper Mechanical, Fluid mecchanics 22 October 2012

ONGC Fluid Mechanics questions with answers,All IT and Non IT (PSU companies) BHEL BEL,HAL,HIL,etcc,bank,IBPS,PO,clerical and all banks solved questions with answerrs and detailed explanations,ONGC model question for practice,ONGC practice question for all engineering streams,ONGC topicwise questions

1. Pascal-second is the unit of
a) pressure
b) kinematic viscosity
c) dynamic viscosity
d) surface tension
Ans: c

2. An ideal fluid is
a) one which obeys Newton,s law of viscosity
b) frictionless and incompressible
c) very viscous
d) frictionless and compressible
Ans: b

3. The unit of kinematic viscosity is
a) gm/cm-sec2
b) dyne-sec/cm2
c) gm/cm2-sec
d) cm2/sec
Ans: d

4. If the dynamic viscosity of a fluid is 0.5 poise and specific gravity is 0.5, then the kinematic viscosity of that fluid in stokes is
a) 0.25
b) 0.50
c) 1.0
d) none of the above
Ans: c

5. The viscosity of a gas
a) decreases with increase in temperature
b) increases with increase in temperature
c) is independent of temperature
d) is independent of pressure for very high pressure intensities
Ans: b

6. Newton,s law of viscosity relates
a) intensity of pressure and rate of angular deformation
b) shear stress and rate of angular deformation
c) shear stress, viscosity and temperature
d) viscosity and rate of angular deformation
Ans: b

7. An open tank contains 1 m deep water with 50 cm depth of oil of specific gravity 0.8 above it. The intensity of pressure at the bottom of tank will be
a) 4 kN/m2
b) 10 kN/m2
c) 12 kN/m2
d) 14 kN/m2
Ans: d

8. The position of center of pressure on a plane surface immersed vertically in a static mass of fluid is
a) at the centroid of the submerged area
b) always above the centroid of the area
c) always below the centroid of the area
d) none of the above
Ans: c

9. The total pressure on a plane surface inclined at an angle 9 with the horizontal is equal to
a) PA
b) pA sin 9
c) pA cos 9
d) pA tan 9
where p is pressure intensity at centroid of area and A is area of plane surface.
Ans: a

10. A vertical rectangular plane surface is submerged in water such that its top and bottom surfaces are 1.5 m and 6.0 m res-pectively below the free surface. The position of center of pressure below the free surface will be at a distance of
a) 3.75 m
b) 4.0 m
c) 4.2m
d) 4.5m
Ans: c

11. Centre of buoyancy always
a) coincides with the centre of gravity
b) coincides with the centroid of the volume of fluid displaced
c) remains above the centre of gravity
d) remains below the centre of gravity
Ans: b

12. If the weight of a body immersed in a fluid exceeds the buoyant force, then the body will
a) rise until its weight equals the buoyant force
b) tend to move downward and it may finally sink
c) float
d) none of the above
Ans: b

13. Metacentric height for small values of angle of heel is the distance between the
a) centre of gravity and centre of buoy-ancy
b) centre of gravity and metacentre
c) centre of buoyancy and metacentre
d) free surface and centre of buoyancy
Ans: b

14. A floating body is said to be in a state of stable equilibrium
a) when its metacentric height is zero
b) when the metacentre is above the centre of gravity
c) when the metacentre is below the centre of gravity
d) only when its centre of gravity is below its centre of buoyancy
Ans: b

15. The increase in meta centric height
i) increases stability
ii) decreases stability
iii) increases comfort for passengers
iv) decreases comfort for passengers
The correct answer is
a) (i) and (iii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)
Ans: b

16. A rectangular block 2 m long, 1 m wide and 1 m deep floats in water, the depth of immersion being 0.5 m. If water weighs 10 kN/m3, then the weight of the block is
a) 5kN
b) lOkN
c) 15 kN
d) 20 kN
Ans: b

17. The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as
a) center of gravity
b) center of buoyancy
c) center of pressure
d) metacentre
Ans: c

18. If a vessel containing liquid moves downward with a constant acceleration equal to ,g, then
a) the pressure throughout the liquid mass is atmospheric
b) there will be vacuum in the liquid
c) the pressure in the liquid mass is greater than hydrostatic pressure
d) none of the above
Ans: a

19. When a liquid rotates at a constant angular velocity about a vertical axis as a rigid body, the pressure intensity varies
a) linearly with radial distance
b) as the square of the radial distance
c) inversely as the square of the radial distance
d) inversely as the radial distance
Ans: b

20. An open cubical tank of 2 m side is filled with water. If the tank is rotated with an acceleration such that half of the water spills out, then the acceleration is equal to
a) g/3
b) g/2
c) 2g/3
d) g
Ans: d

21. A right circular cylinder open at the top is filled with liquid and rotated about its vertical axis at such a speed that half the liquid spills out, then the pressure intensity at the center of bottom is
a) zero
b) one-fourth its value when cylinder was full
c) one-half its value when cylinder was full
d) cannot be predicted from the given data
Ans: a

22. The horizontal component of force on a curved surface is equal to the
a) product of pressure intensity at its centroid and area
b) force on a vertical projection of the curved surface
c) weight of liquid vertically above the curved surface
d) force on the horizontal projection of the curved surface
Ans: b

23. A closed tank containing water is moving in a horizontal direction along a straight line at a constant speed. The tank also contains a steel ball and a bubble of air. If the tank is decelerated horizontally, then
i) the ball will move to the front
ii) the bubble will move to the front
iii) the ball will move to the rear
iv) the bubble will move to the rear Find out which of the above statements are correct ?
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (iii) and (iv)
Ans: b

24. The eddy viscosity for turbulent flow is
a) a function of temperature only
b) a physical property of the fluid.
c) dependent on the flow
d) independent of the flow
Ans: c

25. Flow at constant rate through a tapering pipe is
i) steady flow
ii) uniform flow
iii) unsteady flow
iv) non-uniform flow
The correct answer is
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)
Ans: b

26. In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is
a) 22.5 m/sec.
b) 33 m/sec.
c) 40 m/sec.
d) 90 m/sec.
Ans: c

27. When the velocity distribution is uniform over the cross-section, the correction factor for momentum is
a) 0
b) 1
c) 4/3
d) 2
Ans: b

28. Least possible value of correction factor for
i) kinetic energy is zero
ii) kinetic energy is 1
iii) momentum is zero
iv) momentum is 1
The correct statements are
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (iv)
d) (ii) and (iv)
Ans: d

29. If the velocity is zero over half of the cross-sectional area and is uniform over the remaining half, then the momentum correction factor is
a) 1
b) 4/3
c) 2
d) 4
Ans: c

30. If velocity is zero over l/3rd of a cross-section and is uniform over remaining 2/3rd of the cross-section, then the correction factor for kinetic energy is
a) 4/3
b) 3/2
c) 9/4
d) 27/8
Ans: c

31. The continuity equation
pi V,A,= p2V2A2 is based on the following assumption regarding flow of fluid
a) steady flow
b) uniform flow
c) incompressible flow
d) frictionless flow
where pi and p2 are mass densities.
Ans: a

32. Which of the following velocity potentials satisfies continuity equation ?
a) x2y
b) x2-y2
c) cosx
d) x2 + y2
Ans: b

33. The motion of air mass in a tornado is a
a) free vortex motion
b) forced vortex motion
c) free vortex at center and forced vortex outside
d) forced vortex at center and free vortex outside
Ans: d

34. In a forced vortex motion, the velocity of flow is
a) directly proportional to its radial distance from axis of rotation
b) inversely proportional to its radial distance from the axis of rotation
c) inversely proportional to the square of its radial distance from the axis of rotation
d) directly proportional to the square of its radial distance from the axis of rotation
Ans: a

35. Stream lines and path lines always coincide in case of
a) steady flow
b) laminar flow
c) uniform flow
d) turbulent flow
Ans: a

36. Equation of continuity is based on the principle of conservation of
a) mass
b) energy
c) momentum
d) none of the above
Ans: a

37. In steady flow of a fluid, the total accele ration of any fluid particle
a) can be zero
b) is never zero
c) is always zero
d) is independent of coordinates
Ans: a

38. The pitot tube is used to measure
a) velocity at stagnation point
b) stagnation pressure
c) static pressure
d) dynamic pressure
Ans: b

39. Hot wire anemometer is used to measure
a) discharge
b) velocity of gas
c) pressure intensity of gas
d) pressure intensity of liquid
Ans: b

40. The theoretical value of coefficient of contraction of a sharp edged orifice is
a) 0.611
b) 0.85
c) 0.98
d) 1.00
Ans: a

41. Which of the following is used to measure the discharge ?
a) current meter
b) venturimeter
c) pitot tube
d) hotwire anemometer
Ans: b

42. Select the incorrect statement.
a) The pressure intensity at vena contracta is atmospheric.
b) Contraction is least at vena contracta.
c) Stream lines are parallel throughout the jet at vena contracta.
d) Coefficient of contraction is always less than one.
Ans: c

43. Size of a venturimeter is specified by
a) pipe diameter
b) throat diameter
c) angle of diverging section
d) both pipe diameter as well as throat diameter
Ans: a

44. Due to each end contraction, the discharge of rectangular sharp crested weir is reduced by
a) 5%
b) 10%
c) 15%
d) 20%
Ans: a

45. The discharge through a V- notch varies as
a) H1/2
b) H3,2
c) H5/2
d) H5,4 where H is head.
Ans: c

46. Which of the following is an incorrect statement ?
a) Coefficient of contraction of a venturimeter is unity.
b) Flow nozzle is cheaper than venturimeter but has higher energy loss.
c) Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined.
d) None of the above statement is correct.
Ans: d

47. Coefficient of velocity of venturimeter
a) is independent of Reynolds number
b) decreases with higher Reynolds number
c) is equal to the coefficient of discharge of venturimeter
d) none of the above
Ans: c

48. The pressure at the summit of a syphon is
a) equal to atmospheric
b) less than atmospheric
c) more than atmospheric
d) none of the above
Ans: b

49. Ay between two stream lines represents
a) velocity
b) discharge
c) head
d) pressure
Ans: b

50. Coefficient of velocity for Borda,s mouth piece running full is
a) 0.611
b) 0.707
c) 0.855
d) 1.00
Ans: b

51. Coefficient of discharge for a totally submerged orifice as compared to that for an orifice discharging free is
a) slightly less
b) slightly more
c) nearly half
d) equal
Ans: a

52. The major loss of energy in long pipes is due to
a) sudden enlargement
b) sudden contraction
c) gradual contraction or enlargement
d) friction
Ans: d

53. Coefficient of contraction for an external cylindrical mouthpiece is
a) 1.00
b) 0.855
c) 0.7H
d) 0.611
Ans: a

54. Which of the following has highest coefficient of discharge ?
a) sharp edged orifice
b) venturimeter
c) Borda,s mouthpiece running full
d) CipoUetti weir
Ans: b

55. In a Sutro weir, the discharge is proportional to
a) H1/2
b) H3/2
c) H5/2
d) H
where H is head.
Ans: d

56. The discharge over a broad crested weir is maximum when the depth of flow is
a) H/3
b) H/2
c) 2 H/5
d) 2 H/3
where H is the available head.
Ans: d

57. Which of the following statements is correct?
a) Lower critical Reynolds number is of no practical significance in pipe flow problems.
b) Upper critical Reynolds number is significant in pipe flow problems.
c) Lower critical Reynolds number has the value 2000 in pipe flow
d) Upper critical Reynolds number is the number at which turbulent flow changes to laminar flow.
Ans: a

58. For a sphere of radius 15 cm moving with a uniform velocity of 2 m/sec through a liquid of specific gravity 0.9 and dynamic viscosity 0.8 poise, the Reynolds number will be
a) 300
b) 337.5
c) 600
d) 675
Ans: d

59. The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is
a) constant over the cross section
b) parabolic distribution across the section
c) zero at the mid plane and varies linearly with distance from mid plane
d) zero at plates and increases linearly to midpoint
Ans: c

60. If x is the distance from leading edge, then the boundary layer thickness in laminar flow varies as
a) x
b) x
c) x
d) x/7
Ans: a

61. Stanton diagram is a
a) log-log plot of friction factor against Reynolds number
b) log-log plot of relative roughness against Reynolds number
c) semi-log plot of friction factor against Reynolds number
d) semi-log plot of friction factor against relative roughness
Ans: a

62. The depth ,d, below the free surface at which the point velocity is equal to the average velocity of flow for a uniform laminar flow with a free surface, will be
a) 0.423 D
b) 0.577 D
c) 0.223 D
d) 0.707 D
where D is the depth of flow.
Ans: b

63. The boundary layer thickness in turbulent flow varies as
a) x"7
b) x,/2
c) x4/5
d) x3/5
where x is the distance from leading edge.
Ans: c

64. The distance y from pipe boundary, at which the point velocity is equal to average velocity for turbulent flow, is
a) 0.223 R
b) 0.423 R
c) 0.577 R
d) 0.707 R
where R is radius of pipe.
Ans: a

65. If a sphere of diameter 1 cm falls in castor oil of kinematic viscosity 10 stokes, with a terminal velocity of 1.5 cm/sec, the coefficient of drag on the sphere is
a) less than 1
b) between 1 and 100
c) 160
d) 200
Ans: c

66. In case of an airfoil, the separation of flow occurs
a) at the extreme rear of body
b) at the extreme front of body
c) midway between rear and front of body
d) any where between rear and front of body depending upon Reynolds number
Ans: a

67. When an ideal fluid flows past a sphere,
a) highest intensity of pressure occurs around the circumference at right angles to flow
b) lowest pressure intensity occurs at front stagnation point
c) lowest pressure intensity occurs at rear stagnation point
d) total drag is zero
Ans: d

68. With the same cross-sectional area and immersed in same turbulent flow, the largest total drag will be on
a) a circular disc of plate held normal to flow
b) a sphere
c) a cylinder
d) a streamlined body
Ans: a

69. In which of the following the friction drag is generally larger than pressure drag?
a) a circular disc or plate held normal to flow
b) a sphere
c) a cylinder
d) an airfoil
Ans: d

70. For hydro-dynamically smooth boundary, the friction coefficient for turbulent flow is
a) constant
b) dependent only on Reynolds number
c) a function of Reynolds number and relative roughness
d) dependent on relative roughness only
Ans: b

71. The value of friction factor ,f, for smooth pipes for Reynolds number 106 is approximately equal to
a) 0.1
b) 0.01
c) 0.001
d) 0.0001
Ans: b

72. For laminar flow in a pipe of circular cross-section, the Darcy,s friction factor f is
a) directly proportional to Reynolds number and independent of pipe wall roughness
b) directly proportional to pipe wall roughness and independent of Reynolds number
c) inversely proportional to Reynolds number and indpendent of pipe wall roughness
d) inversely proportional to Reynolds number and directly proportional to pipe wall roughness
Ans: c

73. Separation of flow occurs when
a) the pressure intensity reaches a minimum
b) the cross-section of a channel is reduced
c) the boundary layer comes to rest
d) all of the above
Ans: c

74. The ratio of average velocity to maximum velocity for steady laminar flow in circular pipes is
a) 1/2
b) 2/3
c) 3/2
d) 2
Ans: a

75. The distance from pipe boundary, at which the turbulent shear stress is one-third die wall shear stress, is
a) 1/3 R
b) 1/2 R
c) 2/3 R
d) 3/4R
where R is the radius of pipe.
Ans: a

76. The discharge of a liquid of kinematic viscosity 4 cm2/sec through a 8 cm dia-meter pipe is 3200n cm7sec. The type of flow expected is
a) laminar flow
b) transition flow
c) turbulent flow
d) not predictable from the given data
Ans: a

77. The Prartdtl mixing length is
a) zero at the pipe wall
b) maximum at the pipe wall
c) independent of shear stress
d) none of the above
Ans: a

78. The velocity distribution for laminar flow through a circular tube
a) is constant over the cross-section
b) varies linearly from zero at walls to maximum at centre
c) varies parabolically with maximum at the centre
d) none of the above
Ans: c

79. A fluid of kinematic viscosity 0.4 cm2/sec flows through a 8 cm diameter pipe. The maximum velocity for laminar flow will be
a) less than 1 m/sec
b) 1 m/sec
c) 1.5 m/sec
d) 2 m/sec
Ans: b

80. The losses are more in
a) laminar flow
b) transition flow
c) turbulent flow
d) critical flow
Ans: c

81. The wake
a) always occurs before a separation point
b) always occurs after a separation point
c) is a region of high pressure intensity
d) none of the above
Ans: b

82. The maximum thickness of boundary layer in a pipe of radius r is
a) 0
b) r/2
c) r
d) 2r
Ans: c

83. The hydraulic grade line is
a) always above the centre line of pipe
b) never above the energy grade line
c) always sloping downward in the direction of flow
d) all of the above
Ans: b

84. Two pipe systems are said to be equivalent when
a) head loss and discharge are same in two systems
b) length of pipe and discharge are same in two systems
c) friction factor and length are same in two systems
d) length and diameter are same in two systems
Ans: a

85. In series-pipe problems
a) the head loss is same through each pipe
b) the discharge is same through each pipe
c) a trial solution is not necessary
d) the discharge through each pipe is added to obtain total discharge
Ans: b

86. Select the correct statement.
a) The absolute roughness of a pipe de-creases with time.
b) A pipe becomes smooth after using for long time.
c) The friction factor decreases with time.
d) The absolute roughness increases with time.
Ans: d

87. A valve is suddenly closed in a water main in wl.ich the velocity is 1 m/sec and velocity of pressure wave is 981 m/ sec. The inertia head at the valve will be
a) 1 m
b) 10m
c) 100m
d) none of the above
Ans: c

88. The speed of a pressure wave through a pipe depends upon
a) the length of pipe
b) the viscosity of fluid
c) the bulk modulus for the fluid
d) the original head
Ans: c

89. When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wave), the portion of pipe length subjected to maximum head is
a) L/4
b) L/3
c) L/2
d) L
Ans: a

90. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be
a) from reservoir A to reservoirs B and C
b) from reservoir B to reservoirs C and A
c) from reservoir C to reservoirs A and B
d) unpredictable
Ans: c

91. The length of a pipe is 1 km and its diameter is 20 cm. If the diameter of an equivalent pipe is 40 cm, then its length is
a) 32 km
b) 20 km
c) 8 km
d) 4 km
Ans: a

92. Two pipes of same length and diameters d and 2d respectively are connected in series. The diameter of an equivalent pipe of same length is
a) less than d
b) between d and 1.5 d
c) between 1.5 d and 2d
d) greater than 2d
Ans: a

93. The horse power transmitted through a pipe is maximum when the ratio of loss of head due to friction and total head supplied is
a) 1/3
b) 1/4
c) 1/2
d) 2/3
Ans: a

94. The boundary layer thickness at a distance of l m from the leading edge of a flat plate, kept at zero angle of incidence to the flow direction, is O.l cm. The velocity outside the boundary layer is 25 ml sec.
The boundary layer thickness at a distance of 4 m is
a) 0.40 cm
b) 0.20 cm
c) 0.10 cm
d) 0.05 cm
Assume that boundary layer is entirely laminar.
Ans: b

95. Drag force is a function of
i) projected area of the body
ii) mass density of the fluid
iii) velocity of the body
The correct answer is
a) (i) and (ii)
b) (i) and (iii)
c) (ii) and (iii)
d) (i), (ii) and (iii)
Ans: d

96. The correct relationship among displacement thickness d, momentum thickness m and energy thickness e is
a) d > m > e
b) d > e > m
c) e > m > d
d) e > d > m
Ans: d

97. For laminar flow in circular pipes, the Darcy,s friction factor f is equal to
a) 16/Re
b) 32/ Re
c) 64/ Re
d) none of the above where R,, is Reynolds number.
Ans: c

98. Surge wave in a rectangular channel is an example of
i) steady flow
ii) unsteady flow
iii) uniform flow
iv) non-uniform flow
The correct answer is
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (:v)
d) (ii) and (iv)
Ans: d

ONGC Placement Paper : ONGC Placement Paper Civil, Mechanical, Chemical 22 October 2012

ONGC Basic Civil and Mechanical Engineering Question Bank,ONGC previous years solved question papers

SURVEYING AND CIVIL ENGINEERING MATERIALS PART-A (2 Marks)
1. What is surveying?

2. what is the objective of surveying?

3. what is the difference between a plan and a map?

4. what are the two major types of surveying

5. Differentiate between plane surveying and geodetic surveying?

6. How the surveying is classified based on purpose

7. State the principles of surveying.

8. What are the accessories used in chain surveying?

9. Define bearing of a line.

10. What are the systems of bearing

11. What is meant by local attraction & state its effects?

12. Define leveling and state its objectives

13. Define benchmark and state its effects

14. How rocks are classified?

15. What is quarrying & dressing of stones

16. What are the uses of stones?

17. State the uses of cement?

18. State the properties of cement concrete.

19. What is proportioning of concrete?

20. Define workability of concrete.

PART-B .

1. Explain with neat sketch prismatic compass and principles of compass surveying. .

2. Explain with neat sketch 20m chain and principles of chain surveying. .

3. The following staff readings were observed successively with level, the instrumen having been shifted after second and fifth readings 0.870; 1.635; 2.135; 1.280; 2.980 3.125; 0.120; 1.825; 2.765; 2.015 the first reading was taken with the staff held upon a bench mark of elevation +100.00. Enter the readings in level book and final reduced levels. Apply the usual checks. Find also the difference in level between the first and last points .

4. What are the requirements of good building stone & state important varieties of Building stones .

5 The following perpendicular offset were taken at 10 meter intervals from an Survey line to an irregular boundary line 3.145m, 4.30m, 8.20m, 5.60m,7.60m, 4.2m, 5.6m, 4.3m.
Calculate the area enclosed between the survey line, the irregular boundary line, and first and last offsets by the application of a) Average ordinate method b) Trapezoidal rule and c) Simpson’s rule .

6. What are the different types of cement? Explain the properties and uses? .

7. What are the different types of steel? Explain the properties and uses? .


BUILDING COMPONENTS AND STRUCTURES
PART-A
1. State the objectives and requirements of good foundation?

2. Differentiate between shallow foundation and deep foundation.

3. Define bearing capacity of soil.

4. How the stone masonry is classified?

5. Define the following terms.
i) Corbel
ii) Cornice
iii) Coping
iv) String course
v) Through stone

6. Compare stone masonry and Brick masonry

7. Why bonding in brick wall is essential?

8. State the special features of English and Flemish bond.

9. Define beam, column and Lintel.

10. Classify the types of column based on its conditions.

11. State the purpose of plastering.

12. Define Dam, Bridge and classify them

13. What are the basic components of a bridge?

14. What is the purpose of reinforced concrete?

15. Define factor of safety.

PART-B .
1. a. List the six important points to be considered while selecting a site for construction of Dam.
b. Explain differential leveling with a neat sketch.

2. Explain with neat sketch the different types of piles.
3. List out the different types of bond in brick wall and explain any three in detail.

4. Draw a neat sketch of a reinforced cement concrete column and explain.

5. Explain the types of floor suitable for residential and commercial building.

6. Explain briefly the different types of pitched roof coverings.

UNIT- III POWER PLANT ENGINEERING PART-A (2 Marks)

1. What are the types of power plant?

2. What are the parts of thermal power plant?

3. What is the purpose of Surge tank in hydro power plant?

4. Classify the hydro power plant.

5. What is the function of Draft tube?

6. Define Nuclear Fission. Write chain reaction.

7. What is the function of Moderator?

8. Write down the Merits and Demerits of Disel engine power plant.

9. List out the parts of the Gas turbine power plant.

10. Define Pump and Turbine.

11. Define Cavitations.

12. Define Primiming in Centrifugal Pump.

13. What is impulse turbine? Give example

14. What is Reaction turbine? Give example.

PART-B .

1. Explain working principle of thermal Power plant With Neat sketch. .

2. Explain working principle of Nuclear Power plant With Neat sketch. .

3. a) Explain working principle of Hydro Electric Power plant With Neat sketch..
b) Write its advantages and Disadvantages .

4. a) Explain working principle of Disel Engine Power plant With Neat sketch..
b) Write its advantages and Disadvantages .

5. a) Explain working principle of Gas turbine Power plant With Neat sketch..
b) Write its advantages and Disadvantages . .

6. a) With the help of a neat sketch explain the working of Reciprocating Pump .

b) With the help of a neat sketch explain the working of Impulse Turbine .

7. a) With the help of a neat sketch explain the working of Centrifugal Pump .

b) With the help of a neat sketch explain the working of Impulse Turbine .

UNIT IV INTERNAL COMBUSTION ENGINES

PART-A (2 Marks)
1. What is heat engine?

2. Define I.C Engine and E.C. Engine

3. Classify the I.C engine.

4. List out the Part of the I.C. Engine

5. Define the terms: Top Dead Center, Bottom Dead Center.

6. Define the term: Compression Ratio.

7. What do you understand by Scavenging?

8. Define Boiler
.
9. Classify Boilers.

10. Define fire tube boiler and water tube boiler.

11. List out the Boiler Mountings and Accessories.

12. What is the Purpose of a fusible Plug?

PART-B .
1. Describe the principal parts and functions of a Four Stroke Disel engine With Neat Sketch .

2. Describe the principal parts and functions of a Four Stroke Petrol engine With Neat Sketch .

3. Describe the principal parts and functions of a Two Stroke Disel engine With Neat Sketch .

4. Describe the principal parts and functions of a Two Stroke Petrol engine With NeatSketch .

5. Describe the principal parts and functions of any one high pressure boiler With NeatSketch .

6. Describe the principal parts and functions of Babcock Wilcox boiler With Neat Sketch .

UNIT V REFRIGERATION & AIR CONDITIONING

PART-A (2 Marks)

1. Define Refrigeration.

2. Define refrigerant

3. Define C.O.P.

4. Define refrigerant. Give some examples of refrigerant.

5. Give some properties of good refrigerant.

6. Mention some of the applications of refrigeration.

7. Define relative humidity

8. Define psychrometry.

9. Define DBT and WBT.

10. What is a dew point temperature?

11. Define humidity

12. Mention the classification of air conditioning system.

13. Define year–round air conditioning system

PART-B .

1. Explain the principle and working of vapour compression refrigeration system

2. Explain the principle and working of the vapour absorption refrigeration system

3. Give the comparison of vapour absorption with vapour compression refrigerationsystem

4. Explain the summer air-conditioning system for hot and dry weather

5. With the neat sketch explain the layout of a window room air conditioning

6. Explain the layout of the split type air conditioning system

7. Mention and explain the different types of refrigerant used

8. Explain the advantages and disadvantages of the window air conditioning unit

ONGC Placement Paper : ONGC Placement Paper Electrical Engineering 19 October 2012

ONGC :Graduate Trainees selection Process
ONGC GT (Graduate Trainess) Time Limit 03 Hours
ONGC GT (Graduate Trainess) ELECTRICAL ENGINEERING-208-2009 questions

1 A single phase transformer is connected to a supply of voltage V and frequency f and is supplying a load, connected across its secondary winding. If the supply voltage is reduced from V to V/2, the flux established in the core will
decrease by nearly 50%
increase by nearly 50%
remain unchanged
be affected by amount of load and not by the applied voltage

2 Under magnetic saturation of the core of a transformer, the reactance parameters of its equivalent circuit are affected such that
X1 and X2 increase while Xm does not change
X1 and X2 do not change while Xm decreases
X1 and X2 do not change while Xm increases
X1 and X2 decreases while Xm does not change

3 A single phase 2000/200 V, 10 kVA, two winding transformer is reconnected as a step-up autotransformer with 2000 V winding as primary. The kVA rating of the autotransformer shall be
10 kVA
11 kVA
110 kVA
220 kVA

4 The power factor at which power is drawn by a transformer is
very low under O.C. test but high under S.C. test
high under O.C. test but low under S.C. test
low both under O.C. and S.C. tests
high both under O.C. and S.C. tests

5 The O.C.C. of a shunt d.c. generator is represented by E = 12+66I. If the field resistance is 70 ohms, the no-load voltage of the generator will be
144 V
210 V
220 V
288 V

6 In d.c. shunt motors, the developed torque is proportional to
induced e.m.f.
armature current
output power
line current

7 The speed of a separately excited d.c. motor can be controlled below base speed by (a) armature resistance control and (b) supply voltage control. What happens to the slope of modified speed-torque characteristics under the two methods?
It changes in both types of control
It remains unchanged in both types of control
It remains unchanged in armature resistance control while changes in supply voltage control
It remains unchanged in supply voltage control while changes in armature resistance control


8 The polarity of interpoles used in d.c. machines is
same as the main pole ahead in generators while opposite of the main pole ahead in motors
same as the main pole ahead ion motors while opposite of the main pole ahead in generators
same as the main pole ahead in both motors and generators
opposite of the main pole ahead in both motors and generators


9 In synchronous generators, examine the following statements about voltage regulation:
Synchronous impedance method gives pessimistic results
MMF method gives optimistic results
In unsaturated machine both methods (synchronous impedance and MMF) give same result

Which of the statements are correct?
1, 2 and 3
Only 1 and 2
Only 3
Only 2 and 3

10 Under symmetrical short circuit of a synchronous generator, the armature reaction is
magnetizing
demagnetizing
cross-magnetising
mainly magnetising


11 In synchronous generators, the fifth harmonic in induced emf can be eliminated by using coils show chorded by an angle
9o
18o
27 o
36o


12 In induction motor operation, a slip greater than 1 refers to
regenerative braking
motoring in reverse direction
plugging
dynamic braking


13 As the applied voltage to an induction motor, operating under no-load, is reduced to half
its speed reduced and stator current increases
its speed reduced and stator current also reduces
its speed reduces but there is not change in stator current
there is no change in speed but stator current reduces


14 A 3-phase induction motor is delivering a load of 10 kW at a lagging p.f. of 0.5. If a 3-phase capacitor bank of 7.3 kVAR is connected at its input, the resulting kVA drawn from supply shall be (approximately)
26.5
24.5
20.0
14.0


15 An electric motor developing a starting torque of 10 Nm starts with a load of 6 Nm at its shaft. If the acceleration at start is 2 rad/sec2 , the moment of inertia of the system must be
2 kg-m2
2 N-m2
0.5 kg-m2
0.5 N-m2


16 A synchronous motor works as a synchronous condenser if
underexcited
overexcited
excited with 100% excitation
unexcited


17 In relation to damper bar winding in a synchronous motor, examine the following statements:
Damper bars are provided in slots on poles
Damper bars improve excitation
Damper bars help the motor self start
Damper bars minimize hunting.

Which of the statements are correct?
1, 2, 3
2, 3
1, 4
1, 3, 4


18 In large power ratings, synchronous motor is considered superior to induction motor, since
it is less expensive
its efficiency is better
it can be operated at better power factor
its speed regulation is superior.


19 An induction motor drive is designed for two speed operation. For this purpose, the motor is provided with two windings on its stator corresponding to 4 poles and 8 poles. While the motor was running on 4 pole winding, a changeover to 8 pole winding is made. The motor will
experience dynamic braking
experience regenerative braking
experience no braking but will slow down due to its inertia
draw dangerously high current

20 A d.c. shunt motor drive of 100 h.p. is run (a) at half the rated speed by armature voltage control and (b) at 1.5 times the rated speed by field control. Its power rating in the two cases shall be modified as
100 h.p. in both cases
50 h.p. in case (a) and 150 h.p. in case (b)
50 h.p. in case (a) and 100 h.p. in case (b)
100 h.p. in case (a) and 150 h.p. in case (b)


21 A single phase full controlled rectifier can work as inverter, if the firing angle is between
0o and 90o
60o and 90o
90o and 180o
0o and 60o


22 When d.c. voltage is converted to a.c. by an inverter, PWM technique is used to
control only the output voltage from within the inverter
control both the output voltage and frequency from within the inverter
control the output current
reduce losses in the inverter


23 A thyristor which is in ON state is to be switched OFF. For this purpose a reverse bias is applied across it. Examine the following statements regarding flow of current from anode to cathode (forward current):
Forward current can continue to flow if the circuit is purely resistive
Forward current can continue to flow if the circuit is dominantly inductive
Forward current can continue to flow if the circuit is dominantly capacitive
Forward current will immediately stop flowing.

24 Which of the above statements are correct?
Only 4
Only 1
Only 2 and 3
Only 2


25 In a 3-phase full controlled thyristor bridge rectifier operating under continuous conduction mode, each thyristor conducts for
180o and two thyristors conduct at a time
120o and three thyristors conduct at a time
180o and three thyristors conduct at a time
120o and two thyristors conduct at a time


26 A single phase fully controlled rectifier is feeding a d.c. motor. At a = 0o, the armature voltage is 200 V and motor speed is 1000 rpm. Neglecting armature resistance and considering continuous conduction, the armature voltage and speed at a = 60o will be
100 V and 500 rpm
100 V and 1000 rpm
200 V and 500 rpm
100 V and speed will depend upon load


27 The grading capacitors are provided across the series connected interrupters in EHV circuit breakers for
reducing short circuit current
improving power factor
equalizing distribution of recovery voltage across the interrupters
preventing inductive current chopping.


28 The minimum cost operating condition for a thermal plant is that
the larger units should generate more power as compared to smaller units
the smaller units should generate more power as compared to larger units
the incremental cost rate of the units be proportional to their rating
the incremental cost rate of all the units be equal


29 The effect of earth on a three-phase transmission line is to
increase its capacitance and decrease inductance
decrease its capacitance and increase inductance
increase its capacitance without affecting inductance
increase its inductance without affecting capacitance.

30 In case of a transmission line if the voltage regulation is negative, then the load power factor is
zero
lagging
unity
leading

ONGC Placement Paper : Hyderabad

1) General Awareness
2) Subjective test.

In First Paper there are 50 multiple choice questions. In out of 50 we have to attempt any 40 questions(40*1=40). And 2 descriptive question.(2*5=10)
Questions on longest, biggest, tallest like all facts.
Ex. In India which state have more population density.
2) Who started muslim league.

Descriptive question are
1)As an ONGC employe how do you conserve energy in plant.
2). How do you conserve energy in India .

In paper two there are 75 multi choice questions. Out of 75 we have to attempt 60 only]
(60*1.5=90marks) And 2 descriptive question.(2*5=10).
In subject also they asked about basics only
Ex. 1) What is the first law of thermodynamics.
2). What is magnetic flux .
3) What is B-E constant.

Any way I wrote well. Now I am working for HPCL (onroll).My dear friends prepare well for the exam.

ONGC Placement Paper : Ahmedabad

General Awareness section(Objective questions):
1. Recently Sea link started in which Indian city?

2. What is operation Black-Board related to?

3. Who wrote ‘Discovery of India’?

4. Who wrote ‘My country, My life’?

5. Highest peak of Nilgiri Hills?
6. Largest Botanical garden in india is situated in which city?
7. Cyclone Nargis hits which country most worstly?
8. International date line passes through which sea or ocean?
9. Asia,s first human DNA bank in which city?
10. What is green banking?
11. Which indian cricketer scored triple century in test cricket?
12. Army Operation ,Hand to Hand, is joint operation of India and which other country?
13. Kuchipudi dance belongs to which state?
14. What is the name of first indian nuclear submarine?
15. Mascot of Commonwealth games 2010?
16. What is project arrow related to?
17. Who is the chairman of Planning commission of India?

Descriptive questions(General awareness):

1. Write in brief about global awareness against terrorism?

2. Effect on economy in recent recession time?

Descriptive questions(Electrical):

1. Speed control of shunt & series motors and compare thier merits & demerits?

2. Why is parallel operation of alternators required and conditions for parallel operation?
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