Oil India Limited Placement Papers Ramco Placement Papers Rockwell Placement Papers3i Placement PapersABB Placement PapersAccel Frontline Placement PapersAccenture Placement PapersAcumen Software Placement PapersAditi Placement PapersAdobe Placement PapersADP Placement PapersAgile Placement PapersAgreeya Placement PapersAIG Placement PapersAkamai Placement PapersAks Software Systems Placement PapersAlcatel Placement PapersAllahabad Placement PapersAlle Placement PapersALLFON Placement PapersAlter Placement PapersAlumnus Placement PapersAmdocs Placement PapersAMI Placement PapersAndhra Bank Placement PapersANZ Placement PapersAppLabs Placement PapersAricent Placement PapersASDC Placement PapersAshok Placement PapersAshok LeyLand Placement PapersAspire Placement PapersASPNET Placement PapersAST Pvt Ltd Placement PapersAsto Placement PapersAtlas Placement PapersAxentis Soft Placement PapersAxes Placement PapersAztec Placement PapersBAAN Placement PapersBajaj Placement PapersBank Of Maharashtra Placement PapersBARC Placement PapersBEL Placement PapersBEML Placement PapersBently Placement PapersBFL Placement PapersBHEL Placement PapersBirlasoft Placement PapersBlueStar Placement PapersBOB Placement PapersBOSCH Placement PapersBPL Placement PapersBrakes Placement PapersBSNL Placement PapersC-DOT Placement PapersCadence Placement PapersCalsoft Placement PapersCampaq Placement PapersCanarys Placement PapersCapgemini Placement PapersCaritor Placement PapersCarrizalsoft Technologies Placement PapersCarrizalsoft Technologies Pvt Ltd Placement PapersCaterpillar Placement PapersCD Placement PapersCDAC Placement PapersCelstream Placement PapersCGI Placement PapersChangepond Placement PapersChatargee Placement PapersCisco Placement PapersCiticorp Placement PapersCMC Placement PapersCOGNIZENT Placement PapersComputer Placement PapersConsagous Placement PapersConsagous Technologies Placement PapersConvergys Placement PapersCORDYS Placement PapersCOSL Placement PapersCovansys Placement PapersCrompton Placement PapersCSC Placement PapersCTS Placement PapersDaimler Placement PapersDell Placement PapersDeloitte Placement PapersDelphi-tvs Placement PapersDeutsche Placement PapersDharma Placement PapersDigital Placement PapersdMtechnologies Placement PapersDot Placement PapersDot Com Infoway Placement PapersDRDO Placement PapersDSL Placement PapersDSQ Placement PapersDSRC Placement PapersE2E Placement PapersEasyTech Placement PapersEDS Placement PapersEFFIGENT Placement Papersefunds Placement PapersEIL Placement PapersELGI Placement PapersELICO Placement PapersEnercon Placement PapersEpson Placement PapersEricssion Placement PapersEssar Placement PapersFCG Placement PapersFidelity Placement PapersFlextronics Placement PapersForbes Placement PapersFORCE Placement PapersFuture Placement PapersFX Placement PapersFX Labs Placement PapersG2One Network Private Limited Placement PapersGDA Placement PapersGE Placement PapersGenpact Placement PapersGeodesic Placement PapersGeometric Placement PapersGlobal Placement PapersGodrej Placement PapersGoogle Placement PapersGrapcity Placement PapersGSSL Placement PapersHAL Placement PapersHCL Placement PapersHCL Technologies Placement PapersHello Placement PapersHexaware Placement PapersHFCL Placement PapersHindustan Placement PapersHo Placement PapersHoneywell Placement PapersHorizon Placement PapersHP Placement PapersHPCL Placement PapersHSBC Placement PapersHuawei Placement PapersHughes Placement PapersI-Flex Placement PapersI-Gate Placement Papersi2 Placement PapersIBM Placement PapersIBPS Placement PapersIBS Placement PapersICICI PO DRIVE Placement PapersIDBI Placement PapersIikanos Placement PapersIindus Placement PapersIkosindia Placement PapersImpetus Placement Papersinautix Placement PapersIndian Overseas Bank Placement PapersIndusTeqsite Placement PapersInfineon Placement PapersInformatica Placement PapersInfosys Placement Papersinfotech Placement PapersInphlox Placement PapersIntec Placement PapersIntegra Placement PapersIntegraphr Placement PapersInterwoven Placement PapersIntex Placement PapersIOCL Placement PapersIonnor Solutions Placement PapersiSoft Placement PapersIspat Placement PapersISRO Placement PapersIttiam Placement PapersIvega Placement PapersJ&B Placement PapersJataayu Placement PapersJean Placement PapersJean Martin Placement PapersJet Placement PapersJEYPEE Placement PapersJindal Placement PapersJKT Placement PapersJOHN Placement PapersKalam Software Technology Placement PapersKanbay Placement PapersKeane Placement PapersKenexa Placement PapersKkshema Placement PapersKleward Placement PapersKnoah Solutions Placement PapersKPIT Placement PapersKPIT Cummins Placement PapersL&T Placement PapersL&T Infotech Placement PapersL&T(EEC) Placement PapersLCube Placement PapersLG Placement PapersLG Soft India Placement PapersLifetree Placement PapersLinkwell Placement PapersLionBridge Placement PapersLogica Placement PapersLucent Placement PapersM-Phasis Placement PapersMA Placement PapersMANGANESE Placement PapersMascot Placement PapersMastek Placement PapersMatrix Placement PapersMAXSOFT Placement PapersMcAfee Placement PapersMECON Placement PapersMentor Placement PapersMerrill Placement PapersMicrosoft Placement PapersMindfire Solutions Placement PapersMindtree Placement PapersMiraclesoft Placement PapersMistral Placement PapersMotorola Placement PapersMTNL Placement PapersNagarro Placement PapersNalko Placement PapersNCR Placement PapersNess Placement PapersNest Placement PapersNewgen Placement PapersNFL Placement PapersNHPC Placement PapersNihilent Placement PapersNIIT Placement PapersNovartis Placement PapersNovell Placement PapersNTPC Placement PapersNucleus Placement PapersNYROS TECHNOLOGY Placement PapersOil Placement PapersONGC Placement PapersOnline Education Placement PapersOnMobile Placement PapersOracle Placement PapersOrange Placement PapersParagon Placement PapersPCS Placement PapersPDIL Placement PapersPentaware Placement PapersPentaware Tech Placement PapersPerot Placement PapersPersistent Placement PapersPhilips Placement PapersPlanetasia Placement PapersPNESTEC Placement PapersPolaris Placement PapersPoor Placement PapersPramati Placement PapersProdEx Placement PapersPSI Placement PapersQuark Placement PapersQuinnox Placement PapersQwest Placement PapersR Placement PapersRamco Placement PapersRapidigm Placement PapersRBI Placement PapersRedpine Placement PapersReliance Placement PapersReliance(RIL) Placement PapersRinl Placement PapersRipples Infolink Placement PapersRobert Placement PapersRobert Bosch Placement PapersRockwell Placement PapersRRB(Railway Placement PapersRRB(Railway Recruitment Board ) Placement PapersRSsoftware Placement PapersSahi Placement PapersSail Placement PapersSamsung Placement PapersSamtel Placement PapersSAP Placement PapersSapient Placement PapersSasken Placement PapersSatyam Placement PapersSBI Placement PapersScandent Placement PapersSchneider Placement PapersSCT Placement PapersSemanticSpace Placement PapersShriram Placement PapersSIEMENS Placement PapersSierra Placement PapersSkyTECH Placement PapersSLK Software Placement Paperssobha Placement PapersSoftSol Placement PapersSonata Placement PapersSony India Placement PapersSQL Placement PapersSQL Star Placement PapersSSC Placement PapersStarent Placement PapersStarent Networks Placement PapersSTMicroelectronics Placement PapersSubex Placement PapersSUN Placement PapersSuther Placement PapersSynergy Placement PapersSynopsys Placement PapersSyntel Placement PapersSystech Solutions Placement PapersTalisma Placement PapersTata Placement PapersTata Technologies Placement PapersTavant Placement PapersTCE Placement PapersTCS Placement PapersTech Placement PapersTech Mahindra Placement PapersTELCO Placement PapersTelserra Placement PapersTEMNOS Placement PapersTesco Placement PapersTexas Placement PapersThermax Placement PapersThink Placement PapersTHOROGOOD Placement PapersThoughtWorks Placement PapersTIL Placement PapersTISL Placement Paperstorry Placement PapersTriad Placement PapersTriam Placement PapersTrianz Placement PapersTrilogy Placement PapersTSPL Placement PapersTVS Placement PapersUbiNetics Placement PapersUnited Placement PapersUnited Health Group Placement PapersUS Placement PapersValueLabs Placement PapersValueOne Placement PapersVariFone Placement PapersVedanta Placement PapersVerchaska Placement PapersVERITAS Placement PapersVerizon Placement PapersVernalis Placement PapersVirtusa Placement PapersVisual Placement PapersVIT Placement PapersVizag Steel Plant Placement PapersVizual Placement PapersVSNL Placement PapersVsworx Placement PapersWBPDCL Placement PapersWepIndia Placement PapersWilco Placement PapersWipro Placement PapersXansa Placement PapersXcino Placement PapersYahoo Placement PapersYantro Placement PapersYASH Placement PapersZenith Placement PapersZenser Placement PapersZTE Placement Papers

Download drdo Placement Papers in MS Word and PDF Format for Job Interview

DRDO Placement Paper : DRDO(CEPTAM) Placement Paper Chemical Engineering 10,11,12 Question Papers 30 Nov 2012

DRDO Examination 2008 Stream - Chemical Engineering

Section - A

1. Nitric acid is manufactured by :

(a) Le Blanc process

(b) Haber process

(c) Ostwald process

(d) Solvay process

2. In the Kraft process for paper manufacture, the reagents used in the digestor are :

(a) sodium hydroxide, sodium sulfide and sodium carbonate

(b) magnesium bisulfite and sulfur dioxide in acid medium

(c) sodium sulfite, sodium carbonate and sodium bicarbonate

(d) sodium sulfite, sodium bisulfite and sulfur dioxide

3. In the ,Contact Process, for the manufacture of sulfuric acid, the catalyst used is:

(a) Fe2O3

(b) V2O5

(c) Pt-Rh

(d) AlCl3

4. Match the following

1. Hydrogen from light petroleum stock

2. High-octance gasoline from naphtha

3. Gasoline from gas oil

4. Petroleum coke from residue

P. Pyrolysis

Q. Catalytic cracking

R. Platforming

S. Steam-reforming

(a) 1-P, 2-R, 3-Q, 4-S

(b) 1-P, 2-Q, 3-R, 4-S

(c) 1-S, 2-R, 3-Q, 4-P

(d) 1-R, 2-S, 3-P, 4-Q

5. Among the four fuels listed below, the calorific value is the highest for :

(a) coal

(b) kerosene

(c) natural gas

(d) furnace oil

6. Match the following

1. Cane sugar P. Membrane cell

2. Polyvinyl chloride Q. Urea

3. Caustic soda R. Black-strap molasses

4. Ammonia S. Emulsion polymerization

(a) 1-R, 2-S, 3-P, 4-Q

(b) 1-P, 2-Q, 3-R, 4-S

(c) 1-S, 2-R, 3-Q, 4-P

(d) 1-R, 2-S, 3-Q, 4-P

7. The correct relation between nominal interest rate (r) and effective interest rate (ieff) is:

(a) ieff = er + 1

(b) ieff = er - 1

(c) ieff = er

(d) ieff = r

8. In Guthrie,s cost correlation, cost of a heat exchanger is expressed as a function of :

(a) LMTD

(b) overall heat transfer coefficient

(c) heat duty

(d) surface are

9. A mixture of components A,B,C and D with relative volatilities in the order A B C D is to be separated by a series of distillation columns. The number of possible sequences for this operation is

(a) 14

(b) 20

(c) 10

(d) 5

10. The cost component which is not considered in the estimation of the payout time (i.e. payback period) of a process is:

(a) startup cost

(b) fixed capital

(c) depreciation

(d) working capital

11. A heat exchanger network without any loop has 4 streams above the pinch and 3 streams below the pinch. One utility is available above the pinch and another is available below the pinch. The total number of heat exchangers for this network is :

(a) 10

(b) 8

(c) 6

(d) 7

12. The measure of profitability of the process that does not take into account time value of money is :

(a) discounted cash flow rate of return

(b) capital charge factor

(c) payback period

(d) return on investment

13. The response of a system, G(s) = 1/tS + 1 for a step change of magnitude A is equal to :

(a) 1 - et/t

(b) A (1 - et/t)

(c) A (1 - e-t/t)

(d) 1 - e-t/t

14. The Laplace transform of the input function, u (t), given in Fig. Q 14 is:

(a) 1/5s2 (1 - e-3S)

(b) 1/5s2 (1 + e-3S)

(c) 3/5s2 (1 - e-3S)

(d) 3/5s2 (1 + e-3S)

15. A system with transfer function G (s) = S/S + 1 is subjected to a sinusoidal input u(t) = sin wt. At steady state, the phase angles of the output relative to the input at w = 0 and w = will be, respectively :

(a) 0 and - p/2

(b) p/2 and 0

(c) -p/2 and 0

(d) 0 and p/2

16. For the response of an under damped second order process:

(a) overshoot = (decayratio)0.5

(b) overshoot = decayratio

(c) overshoot = (decayratio)2

(d) overshoot = (decayratio)-1

17. The connecting line of the type denotes:

(a) electric signal

(b) capillary tubing

(c) software link

(d) pneumatic signal

18. Match the following :

1. Hot wire anemometer P. Temperature measurement

2. DP cell Q. Flow measurement

3. Pyrometer R. Pressure measurement

(a) 1-P, 2-Q, 3-R

(b) 1-Q, 2-R, 3-P

(c) 1-P, 2-R, 3-Q

(d) 1-R, 2-P, 3-Q

19. When two first order processes are connected in a non-interacting manner the combined system will be :

(a) second order under damped

(b) second order over damped

(c) second order critically damped

(d) first order

20. The best method for controlling the temperature of a catalytic exothermic reaction taking place in a tubular reactor is:

(a) cascade control

(b) override control

(c) split-range control

(d) auctioneering control

21. U-tube manometer is a :

(a) zero order process

(b) first order process

(c) second order process

(d) third order process

22. The final value of f (s) = S/S2 + 3S + 2 is given by :

(a) 1

(b) 0

(c) 2

(d) 3

23. The equation (s) representing the linear system (s) is (are) : -

(I) d2y/dt2 + 8 dy/dt + y = u(t)

(II) (y + 7) dy/dt = 8 u(t)

(III) 3 d2y/dt2 + 2 dy/dt +3y = u2(t)

(a) I only

(b) I and II

(c) II only

(d) III only

24. Match the transfer functions with the responses to a unit step input, shown in the Fig.

(I) G (s) = -3 (-4S + 1)/4s2 + 4s + 1

(II) G (s) = -2e-15s/ 10s + 1

(III) G (s) = -5/-15s + 1

(IV) G (s) = -0.2/s

(V) G (s) = 5s + 3/4s + 1

(a) I-C, II-E, III-D, IV-A, V-B

(b) I-E, II-C, III-A, IV-D, V-B

(c) I-E, II-A, III-C, IV-B, V-D

(d) I-A, II-C, III-E, IV-B, V-D

Statements for linked Answer Question 25 and 26:

Following is the Bode diagram of a process.

25. The ultimate gain of the process is :

(a) 8.33

(b) 4.99

(c) 12.55

(d) 1.21

26. The ultimate period of sustained cycling of the process is :

(a) 0.01 min/cycle

(b) 0.37 min/cycle

(c) 0.89 min/cycle

(d) 0.53 min/cycle

27. An elementary reaction is expressed as : A + B → C. The unit of the rate constant for this reaction is :

(a) 1/s

(b) mol/(m3.s)

(c) m3/(mol - s)

(d) m3 - s/mol

28. The RTD function E(t) for a CSTR with average residence time, t is :

(a) exp(-t/t)/t

(b) d(t - t)

(c) t/t

(d) exp(-t/t)

29. The flow-pattern inside a reactor resembles plug flow when the dispersion number is :

(a) 1

(b) <0.01

(c) 10 - 100

(d) >100

30. Consider the elementary liquid-phase reaction A→ B → C carried out in a CSTR under steady state. The rate equations for A and B are: -rA = 100 CA and rB = 100 CA - CB and /(m3.s), respectively. If there is no product in the feed, the value of residence time corresponding to the maximum concentration of B is :

(a) 0.1 s

(b) 10 s

(c) 100 s

(d) 0.01 s

31. Consider the liquid-phase reactions shown in the schematic below carried out in a flow reactor at steady state.

Keeping the reaction-system isothermal, the yield of the desired product can be maximized by maintaining :

(a) low concentration of A and high concentration of B

(b) high concentration of A and high concentration of B

(c) low concentration of A and low concentration of B

(d) high concentration of A and low concentration of B

32. The first-order gas-phase reaction : A → 3R is carried out in a variable-volume CSTR at constant temperature and pressure. If the conversion is 60%, the Damkohler number is :

(a) 2.5

(b) 1.8

(c) 3.3

(d) 4.6

33. The Hatta number is a measure of :

(a) rate of reaction/rate of mass transfer

(b) rate of bulk reaction/rate of surface reaction

(c) rate of adsorption/rate of desorption

(d) rate of reaction at the room temperature/rate of reaction at the reaction temperature

34. Pores of a catalyst pellet can be represented as shown in Fig

The porosity of the catalyst pellet is 0.5 and constriction factor is 0.8. If the Knudsen diffusivity of a gas is 1.4 x 10-6 m2/s, its effective diffusivity is :

(a) 4 x 10-7 m2/sss

(b) 1.3 x 10-8 m2/s

(c) 2 x 10-7 m2/s

(d) 1.4 x 10-6 m2/s

35. Thiele modulus is a measure of :

(a) rate of diffusion through the catalyst pellet/surface reaction rate

(b) bulk diffusivity/Knudsen diffusivity

(c) surface rection rate/rate of diffusion through the catalyst pellet

(d) actual overall rate of rection/rate of reaction that would result if the entire interior surface were exposed to the external pellet surface concentration at the surface temperature

36. An elementary liquid-phase reaction : A → B is to carried out in a PFR operated under steady state at constant temperature and pressure. The flow rate of A is 1 mol/s, the concentration of A in the feed is 1 mol/m3 and the value of the rate constant is 1 s-1. The volume of the reactor required for 90% conversion of A is :

(a) 3.7 m3

(b) 2.3 m3

(c) 4.6 m3

(d) 12.6 m3

37. A liquid-phase reaction is being carried out in a constant-volume batch reactor. The rate constant is 0.01 s-1. The initial concentration of the reactant fed to the reactor is 1 mol/m3. The concentration of the reactant after 100 s is :

(a) 1/e mol/m3

(b) 2.3 mol/m3

(c) e mol/m3

(d) 0.1 mol/m3

38. A reaction is being carried out in a set of two CSTRs in series under steady state. The reaction rate constant is 0.1 s-1 and the residence time is 10s in each reactor. Assuming no change in volume, the conversion of the reactant after the second reactor is:

(a) 50%

(b) 25%

(c) 100%

(d) 75%

Statement for linked answer question 39 and 40 : A liquid feed containing 40 mol% A and 60 mol%, B is distilled in a column. The distillate composition is 90 mol% A and 10 mol% B. The average heat capacity of the feed is 100 kJ/(kmol-K). The average latent heat of feed is 30 MJ/(kmol-K). The inlet temperature and bubble point of the feed are 350 K and 500 K respectively. The point of intersection of the q-line with the equilibrium curve is (0.5,0.7). Assume Mc-Cabe-Thiele method of distillation to be applicable for this operation.

39. The q-factor this operation is

(a) 3

(b) 2.5

(c) 1.5

(d) 1

40. The minimum reflux ratio for this operation is :

(a) 2

(b) 1

(c) 1.5

(d) 2.5

Statement for linked answer question 41 mid 42 : An organic vapor in exhaust air from a process is recovered by adsorption onto activated carbon. The diameter of the absorbent bed is 0.15 m and the height is 0.6 m. The time equivalent of stoichiometric bed capacity is 4.8 x 104s and the time equivalent of bed capacity up to breakpoint is 2.4 x 104s.

41. The length of unused bed for this operation is :

(a) 0.1 m

(b) 0.3 m

(c) 0.4 m

(d) 0.2 m

42. For a new adsorption column to be installed for the same question, the desired break-point time is 3.6 x 104s. The total length of the new column should be :

(a) 0.8 m

(b) 1 m

(c) 0.75 m

(d) 1.5 m

Statement for linked answer question 43 mid 44 : Consider a mixture of vapor (A) and dry gas (B) at 298 K. The molecular weights of A and B are 20 kg/mol and 50 kg/mol respectively. The total pressure of the system is 100 kPa. Vapor pressure of A at 298 K is 25 kPa.

43. If the partial pressure of A is 10 kPa, the humidity of the mixture is approximately equal to :

(a) 0.004 kg A/kg dry B

(b) 0.1 kg A/kg dry B

(c) 0.04 kg A/kg dry B

(d) 0.002 kg A/kg dry B

44. If the humidity of the mixture of A and B is 0.01 kg A/kg dry B, the mole fraction of A in the gas phase is approximately equal to :

(a) 0.015

(b) 0.025

(c) 0.01

(d) 0.005

45. For wet bulb temperature to be equal to adiabatic saturation temperature, Lewis number should be equal to


(b) 0

(c) 10

(d) 1

Statement for linked answer question 46 mid 47 : A gas stream containing component A at 1 mol% is scrubbed with fresh water in a counter current packed tower. It is proposed to remove 90% of A by absorption in water. The gas flow rate is 20 mol/(m2.s) and the liquid flow rate is 100 mol/(m2.s). The equilibrium relationship in terms of mole fraction is given by

y* = 2 x

The mass transfer coefficients are :

kxa = 50mol/(m3.s)

kxa = 25mol/(m3.s)

46. The overall gas-phase NTU based on arithmetic mean driving force is approximately equal to :

(a) 5

(b) 2.5

(c) 7.5

(d) 10

47. The overall gas-phase HTU based on arithmetic mean driving force is approximately equal to :

(a) 2.6 m

(b) 2 m

(c) 1.6 m

(d) 3 m

48. The condition for which HETP of a packed tower is equal to overall gas phase HTU is :

(a) equilibrium curve is parabolic and lies below the operating line

(b) equilibrium curve is parabolic and lies above the operating line

(c) equilibrium and operating lines are orthogonal

(d) equilibrium and operating lines are straight and parallel

49. The condition under which the operating lines for both stripping and rectifying sections coincide with the diagonal in McCabe- Thiele method is :

(a) 1.2 times minimum reflux

(b) minimum reflux

(c) total reflux

(d) no reflux

50. If the moisture content of a solid on dry basis is X, then the moisture content on wet basis is :

(a) X/(I - X)

(b) X/(I + X)

(c) (1 + X)/X

(d) (1 - X)/X

Section - B

51. Moisture in a solid exerting an equilibrium pressure equal to that of pure liquid at the same temperature is called:

(a) bound moisture

(b) free moisture

(c) critical moisture

(d) unbound moisture

Statement for linked answer question ------ and ------ : An antibiotic is extracted from a dilute aqueous solution using a solvent. The volume ratio of solvent to aqueous phase is 0.06. The distribution coefficient of the antibiotic is 50. No appreciable change in volume of aqueous phase as well as solvent is observed with transfer of solute.

52. The percentage recovery of the antibiotic is an ideal single stage with the fresh solvent is :

(a) 75%

(b) 40%

(c) 50%

(d) 80%

53. Approximate percentage recovery of the antibiotic in two ideal stages with the fresh solvent added to both stages with the same volume ratio is:

(a) 80%

(b) 99%

(c) 75%

(d) 94%

54. The steady state temperature distribution in a plane wall is found to be T = 400 + 2000x -10000x2, T is in K and x is in m measured from one side of the wall. The maximum temperature is found at x equal to :

(a) 0

(b) 1

(c) 0.25

(d) 0.5

55. For the composite wall as shown in Fig.

R1, R2, R3 and R4 are the resistance of the different sections. The total resistance for one-dimensional heat flow along x-direction is :

(a) R1 + R2 + R3 + R4

(b) R1R2 + R2R3 + R1R3 + R2R4 + R3R4 / R1 + R2 + R3 + R4

(c) R1R2R3 + R2R3R4 + R2 + R3 / R2R3

(d) R1R2+ R2R3 + R1R3 + R2R4 + R3R4 / R2 + R3

56. Lumped-capacity analysis for heat conduction in a solid wall is applicable when the conductive resistance is :

(a) very low compared to convective resistance

(b) very high compared to convective resistance

(c) comparable with convective resistance

(d) equal to convective resistance

57. Fins do not help much for heat transfer into a boiling liquid because :

(a) boiling liquid is at constant temperature and no heat transfer is possible

(b) boiling liquid has very low convective heat transfer coefficient

(c) boiling liquid has very high convective heat transfer coefficient

(d) it is difficult to put fins in a boiling liquid

58. Heat transfer is taking place from a solid flat surface to a fluid flowing in laminar flow dh and dT are the hydrodynamic and thermal boundary layer thicknesses respectively. The correct statement is :

(a) dh and dT are always same

(b) dh or dT are independent of the momentum or thermal diffusivity respectively

(c) dh > dT, if momentum diffusivity is greater than thermal diffusivity

(d) dh > dT, if momentum diffusivity is lower than thermal diffusivity

59. Rayleigh number is associated with :

(a) radiation

(b) conduction

(c) forced convection

(d) free convection

60. One-dimensional heat transfer through a long slab (without any heat generation or depletion inside) will never reach steady state, if

(a) input heat flux in one boundary is same as the output heat flux in the other boundary

(b) input heat flux in one boundary is more than the output heat flux in the other boundary

(c) temperatures of the two boundaries are maintained at constant values

(d) all of a, b and c

61. A hemisphere of diameter, D is enclosed with a flat surface of diameter, D. The flat surface is designated as surface 1 and the hemisphere is designated as surface 1 and the hemisphere is designated as surface 2. The view factor matrix for the enclosure is :





62. The INCORRECT statement is :

(a) Both Nusselt and Biot numbers indicate ratio of conductive resistance to convective resistance

(b) Both Nusselt and BIot numbers are dimensionless groups

(c) Nusselt number uses thermal conductivity of fluid but Biot number uses thermal conductivity of solid

(d) Both Nusselt and Biot numbers use thermal conductivity of soiled

63. The statement "boiling point of a given aqueous solution is laminar function of the boiling point of pure water at the same pressure" is known as

(a) Duhring,s rule

(b) Raoult,s law

(c) Henry,s law

(d) Colburn analogy.

64. The statement for a single-effect evaporator "1.5 kg steam is consumed per hour" indicates its:

(a) capacity

(b) economy

(c) capacity/economy

(d) economy/capacity

65. Tubes of 80 mm2 cross-sectional area and 29 mm perimeter are arranged in square pitch inside a shell and tube heat exchanger. The tube pitch is 15 mm. The hydraulic diameter for heat transfer at the shell side is :

(a) 29 mm

(b) 40 mm

(c) 15 mm

(d) 20 mm

Statement for linked answer question 66 and 67 : Lubricant oil [specific heat = 2.1 kJ/(kg.K)] with a flow rate of 2 kg/s at 353 K needs to be cooled to 323 K. Water [specific heat = 4.2 kJ/(kg.K)] is available at 303 K and must not be heated above 313 K. The flow occurs in co-current fashion. The overall heat transfer coefficient is 420 W/(m2.K). The area of heat transfer is 12 m2.

66. The effectiveness of the heat exchanger is :

(a) 0.8

(b) 0

(c) 0.6

(d) 0.75

67. The number of transfer units of the heat exchanger is approximately equal to :

(a) 1.2

(b) 1.5

(c) 1.7

(d) 1.0

68. For flow across a tube bundle in a baffled shell and tube heat exchanger, the pressure drop is :

(a) maximum for square pitch

(b) maximum for triangular pitch

(c) maximum for rotated square pitch

(d) independent of pitch arrangement

69. For a constant-pressure filtration process with negligible filter cloth resistance, the volume of filtrate collected per unit area (V/A) varies with corresponding filtration time q through the relationship :

(a) q

(b) √q

(c) q2

(d) q-1

70. The following conditions are applicable for a centrifuge :

Load inside the centrifuge : 10 kg

Diameter of the basket : 50 cm

Rotational speed : 10000 Hz

The force developed by centrifugal action inside the centrifuge is (assume p2= 10)

(a) 10000 N

(b) 10000 kN

(c) 10000 MN

(d) 10000 GN

71. To apply Stokes,s law for free terminal settling of some solid particles (special gravity = 2.8) in water, the maximum diameter of the particles will be approximately equal to :

(a) 45 m

(b) 4.5 m

(c) 450 m

(d) 0.45 m

72. Two impellers with diameters 8 cm and 1 cm have the same power number. The first one rotates with a speed of 10 Hz. The speed of the second impeller is :

(a) 3.2 Hz

(b) 32 Hz

(c) 320 Hz

(d) 3200 Hz

73. Limestone of average diameter 25 mm is being crushed to particles of size 10 mm. If the feed size of the limestone is increased to 40 mm, according to the Rittinger,s law the percentage increase in power requirement to get the same-sized product will be :

(a) 10%

(b) 25%

(c) 40%

(d) 100%

74. Match the following :

1. Water P. Dilatant fluid

2. Toothpaste Q. Newtonian fluid

3. Polymer solution R. Bingham plastic fluid

4. Starch suspension S. Pseudoplastic fluid

(a) 1-Q, 2-R, 3-S, 4-B

(b) 1-P, 2-Q, 3-R, 4-S

(c) 1-R, 2-S, 3-P, 4-Q

(d) 1-S, 2-P, 3-Q, 4-R


Match the following :

1. P. Euler equation

2. Q. Navier-Stokes equation

3. R. Continuity equation

4. S. Bernoulli,s equation.

(a) 1-S, 2-P, 3-Q, 4-R

(b) 1-R, 2-S, 3-P, 4-Q

(c) 1-Q, 2-S, 3-P, 4-R

(d) 1-P, 2-Q, 3-R, 4-S

76. Match the following :

1. Rotameter P. Direct measurement of mass flow rate

2. Notch tube Q. Full-bore meter

3. Orifice meter R. Measurement of local velocity

4. Coriolis meter S. Variable area meter

(a) 1-S, 2-P, 3-Q, 4-R

(b) 1-R, 2-P, 3-P, 4-Q

(c) 1-Q, 2-S, 3-P, 4-R

(d) 1-S, 2-R, 3-Q, 4-P

77. For one dimensional flow (z-direction) of a fluid through a pipe, match the following :

1. Steady flow P. V ≠ f(z)

2. Fully developed flow Q. V ≠ f(r)

3. Uniform flow R. V ≠ f(t)

4. Irrotational flow S. V x V = 0

(a) 1-S, 2-P, 3-Q, 4-R

(b) 1-R, 2-P, 3-Q, 4-S

(c) 1-Q, 2-S, 3-P, 4-R

(d) 1-S, 2-R, 3-Q, 4-P

78. For the velocity profile of a fluid in Cartesian coordinate.

V = xy2i - xy3j + xyk, the flow is :

(a) steady and incompressible

(b) unsteady and incompressible

(c) steady and compressible

(d) unsteady and compressible

79. Bernoulli,s equation is applicable when the flow is :

(a) streamline, unsteady, frictionless and incompressible

(b) streamline, steady, friction and incompressible

(c) streamline, steady, frictionless and compressible

(d) streamline, steady, frictionless and incompressible

80. A pipeline of inside diameter 0.1 m and length 10 m is fitted with two p/2 rad elbows, one p/4 rad elbow and three gate valves. Equivalent lengths of one p/2 rad elbow, one p/4 rad elbow and one gate valves are 30, 16 and 8 respectively. The ratio of minor loss to major loss is :

(a) 0.1

(b) 1

(c) 10

(d) 0

81. Water flows through an annulus of two concentric pipes at a velocity of 0.1 m/s. The outside diameter of the inner pipe is 0.1 m and the inside diameter of the outer pipe is 0.2m. Viscosity of water is 1 mPa-s. The Reynolds number for the flow is :

(a) 2 x 104

(b) 2 x 103

(c) 1 x 104

(d) 1 x 103

82. A cylindrical pump (NPSH requirement = 5 m) draws a non-volatile liquid from reservoir at a pressure of 196 kPa. If the frictional loss of head in the suction line is well within 1m, the minimum lift is :

(a) 10.4 m

(b) 15 m

(c) 20 m

(d) 14 m

83. A cylindrical column has inside volume of 0.02 m3 and 50% of that volume is filled with a packing material of volume 0.006 m3. If the Superficial velocity through the column is 0.1 m/s, the interstitial velocity is :

(a) 0.1 m/s

(b) 0.25 m/s

(c) 4 m/s

(d) 10 m/s

84. In a particulate fluidization experiment, when the velocity is increased by 10 times. The length of the bed of void fraction 0.4 is found to be doubled. The new void fraction is :

(a) 0.7

(b) 0.6

(c) 0.5

(d) 0.8

85. The statement that describes the 3rd law of thermodynamics is :

(a) "All gases having same reduced property behave similarly"

(b) "Heat transfer from low temperature to high temperature source is not possible without external work"

(c) "Crystalline solids have zero heat capacity at absolute zero temperature"

(d) "Energy can neither be created nor be destroyed but can be transformed from one form to another"

86. A gas cylinder contains 1.4 kg of liquid nitrogen. This gas is released and brought to 273 K and atmospheric pressure. The volume occupied by the gas assuming ideal behavior is :

(a) 1.12 m3

(b) 2 m3

(c) 1 m3

(d) 2.24 m3

87. Consider the chemical reaction 4NH (g) + 5O2 (g) = 4NO2(g) + 6H2O (g) with ∆ H = -227 kJ/kmol. The equilibrium yield of NO2 will be maximum at :

(a) high pressure and high temperature

(b) low pressure and high temperature

(c) high pressure and low temperature

(d) low pressure and low temperature

88. The condition for a gas to show maximum deviation from ideal behavior is :

(a) high pressure and low temperature

(b) low pressure and high temperature

(c) high pressure and high temperature

(d) low pressure and low temperature

89. A chemical system comprises of 4 components and 2 phases. The degrees of freedom for the system are :

(a) 2

(b) 4

(c) 6

(d) 0

90. A liquid mixture containing 60 mol% A and 40 mol% B follows Raoult,s law. At 323 K the vapor pressures of pure A and B are 80 kPa and 40 kPa respectively. The equilibrium vapor phase mole fraction of component A at the bubble point, 323 K is :

(a) 0.8

(b) 0.5

(c) 0.9

(d) 0.75

91. The equation which does not follow Maxwell relation is:





92. The correct definition of entropy of a system with constant composition is ;

(a) S =

(b) S =

(c) S =

(d) S =

93. The dimension of viscosity is :

(a) MLT-1

(b) MLT-1 T-1

(c) MLT-2 T-1

(d) MLT-1 T-2

94. A gas containing 1 mole % ethane is in contact with water at 293 K and 2 x 103 kPa. If the Henry,s law constant is 2.5 x 106 kPa/mol fraction, the mole fraction of dissolved ethane in water is :

(a) 2 x 10-4

(b) 8 x 10-2

(c) 1 x 10-3

(d) 8 x 10-6

95. The internal energy of reaction for the reaction C2H4 (g) + 2Cl2 (g) → C2HCl3 (1) + H2(g) + HCl (g) is - 418 kJ/mol at 300 K. The heat of reaction is :

(a) -420.5 kJ/mol

(b) -418 kJ/mol

(c) -416 kJ/mol

(d) -150 kJ/mol

96. The heats of oxidation of magnesium and iron according to the following reactions are :

Mg + O2 → MgO, ∆ H = - 610 kJ

2Fe + O2 → Fe2O3, ∆ H = - 810 kJ

The heat of the reaction of : 3Mg + Fe2O3 → 3MgO + 2Fe is

(a) 2680 kJ

(b) - 830 kJ

(c) 1680 kJ

(d) - 1020 kJ

97. A droplet of water at 298 K is suddenly introduced into an infinite gas medium at 373 K saturated with water vapor. At steady state :

(a) the drop attains wet bulb temperature and vanishes

(b) the drop-row in size and attains the temperature of 373 K.

(c) the drop reduces in size and attains the temperature of 373 K.

(d) the size of the drop remains unaltered and it attains the temperature of 373 K.

98. The coefficient of volumetric expansion for an ideal gas at a pressure, P and temperature, T is :

(a) 1/T

(b) T

(c) P

(d) 1/T2

99. The proximate analysis of coal involves the determination of :

(a) net calorific value

(b) caking index

(c) carbon, hydrogen, nitrogen, sulfur and oxygen

(d) volatile matter, fixed carbon, ash and moisture.

100. The Clausius-Clapeyron equation describes the variation of :

(a) heat capacity with temperature

(b) density with pressure

(c) vapor pressure with temperature

(d) surface tension with temperature

DRDO Placement Paper : DRDO(CEPTAM) Placement Paper Technical and General Awareness 01 Aug 2012

DRDO (CEPTAM)Technical Placement papers(ECE,EEE,CS,Mech Engg ...Management Trainee Questions

DRDO (CEPTAM) whole Test Paper -100 Questions
1. Which of the following regular expressions describes the language- the set of all strings over {0, 1} containing at least two 1s?
A. (0+1)*11(0+1)* B. 0*110*
C. 0*10*10*
D. (0+1)*1(0+1)*1(0+1)*

2. Which of the following is / are regular language(s) ?
I. { ambn | m , n ≥0}
II. {w є {a, b}*| has equal number of a s and b s}
III. {ambn | m>n}
IV. {w є {a , b}* w has even number of a s}
A. Only
B. And only
C. And only
D. Only

3. Which of the following is true?

A. For every NFA there is an equivalent PDA.
B. Nondeterministic TMs are more powerful than deterministic TMs. C. DPDAs and NPDAs are equivalent in power.
D. NFAs accept the class of CFLs.
15. A variable X has been assigned fresh values in statements numbered 6, 9 and
12 in a 25- statement program which does not have any jump instructions.
This variable is used in statements numbered 7, 8, 10, 16 and 17.the statement range where the register, used by the variable X, could be assigned to some other variable are-
A. 8-9, 10- 12, 17- 25
B. 11, 18-25
C. 17-25
D. Non of the above

4. Let L be a CFL. Then L must be
A. CFL but not regular.
B. Recursive.
C. Recursively Enumerable but not Recursive.
D. Regular but not CFL.

5. Which of the following is FALSE?
A. CFLs are closed under union but not closed under complement.
B. Regular sets are closed under intersection and Kleene Closure.
C. Recursive languages are closed under intersection but not closed under complement.
D. Recursively enumerable languages are closed under union and intersection.

6. Which of the following is NOT POSSIBLE?
A. Finding out a minimal DFA for any arbitrary regular language.
B. Constructing a deterministic TM for any arbitrary CFL.
C. Determining whether two CFGs generate the same language.
D. Given an arbitrary TM M (which halts on all inputs) whether the complement of the language accepted by M is recursive.

7. Which of the following is FALSE?
A. Regular expressions and DFAs are equivalent.
B. A DPDA cannot accept by any arbitrary CFL.
C. The language accept by any TMs is a CFL.
D. Complement of every regular language is CFL.

8. Consider the languages L1 and L2 given below.
L1= {| M1 and M2 are NFAs and L (M1 )= L (M2)} L2= {| M1 and M2 are TMs and L (M1 )= L (M2)} Which of the following is true?
A. L1 is undecidable but L2 is decidable.
B. L2 is undecidable but L1 is decidable.
C. Both L1 and L2 are undecidable.
D. Both L1 and L2 are decidable.

9. Let A and B be languages corresponding to two decision problems πA and πB respectively. Let A be NP complete problem, then hat would not B NP.
Which of the following is true?
A. B is NP- complete
B. A proportional p B
C. B proportional p A
D. None of the above.

10. if there is a polynomial time algorithm for an NP- complete problem, then that would not imply which of t he following:
A. P = NP
B. NP = Co- NP
C. P = NP ∩ Co-NP

11. A 1KB RAM can be organized as an 8 K bit RAM.
A. Using a 1 to 8 line demultiplexer.
B. Using an 8 to 1 multiplexer.
C. Using an 8 input OR gate.
D. None of the above.

12. A 2 KB RAM can be economically organized using-
A. 64 numbers of 256 bit RAM chip and a 1/8 line decoder.
B. 64 numbers of 256 bit RAM chip and a 1/64 line decoder.
C. 8 numbers of 256 bit RAM chips and a 1/8 line decoder.
D. 8 numbers of 256 bit RAM chips and a 1/64 line decoder

13. With reference to RETURN instruction, which of the following statement is / are true?
1. The instruction can be used only to take the flow of control back to the program from which it initially jumped.
2.The instruction retrieves the address using the current stack pointer from the stack and alters the control to the program pointed to by it.
3. The instruction works only if the registers used in the main program have been pushed and later popped before its execution.
4.The instruction can be used only in conjunction with the call instruction.
A. 1st and 2nd
B. 2nd only
C. 1st, 2nd and 3rd only
D. All the statement are true

14. In an n- CPU shared bus system, if is the probability that any CPU requests the bus in a given cycle, the probability that only one CPU uses the bus is given by-
A. Nz(1-z)(n-1)
B. Z(1-z)(n-1)
C. N(1-z)n
D. (N-1)z(1-z)

15. A variable X has been assigned fresh values in statements numbered 6, 9 and 12 in a 25- statement program which does not have any jump instructions.
This variable is used in statements numbered 7, 8, 10, 16 and 17.the statement range where the register, used by the variable X, could be assigned to some other variable are-
A. 8-9, 10- 12, 17- 25
B. 11, 18-25
C. 17-25
D. Non of the above

16. If the Intel Pentium processors, was not made compatible to programs written for its predecessor, it could have been designed to be a faster processor.
A. The statement is true
B. The statement is false
C. The speed cannot be predicted.
D. Speed has nothing to do with the compatibility.

17. A certain snooping cache an snoop only an address lines. Which of the following is true?
A. This would adversely affect the system if the write through protocol is used.
B. This would run well if the write through protocol is used.
C. Data snooping is mandatory.
D. None of the above.

18. Repeated occurrence of identical interrupt during execution of this service routine can result in-
A. Program error.
B. Stack overflow.
C. Hardware error.
D. None of the above.

19. Micro programmed control is not fit for RISC architectures because-
A. It tends to slow down the processor.
B. It consumes more chips area.
C. Handling a large number of registers is impossible in micro programmed systems.
D. The 1 instruction / cycle timing requirement for RISC is difficult to achieve for all instructions.

20. A certain RISC processor has 12register windows and 16 global registers. Each window has 8 input, 16 local and 8 output registers. The total number of registers in the processor is

21. In a certain system the main memory access time is 1000 ns. The cache memory is 10 times faster then the main memory uses the write through protocol. If the hit ratio for read request is 0.92 and 85% of the memory requests generated by the CPU are for the read, the remaining being for write, then the average time considering both read and write request is
A. 14.62 ns
B. 348.47 ns
C. 29.62 ns
D. 296.2 ns

22. Shown below are segments of a code run on a CISC and a RISC architecture separately.
MOV BX, 06 MOV BX, 05
MUL AX, BX; Multiply AX with BX MOV CX, 06
LOOP START ; loop till

If the MUL instruction takes 402 clock cycles, which of the following statement is true?

A. The CISC code will faster by a factor of 1.8.
B. The RISC code will run aster by a factor of 2.8.
C. The CISC code will faster by a factor of 0.025.
D. The RISC code will run aster by a factor of 40.

23. The frequent of different types of instructions executed by a machine is tabulated below.
Operand Accessing Mode Frequency in %
register 30
Immediate 20
Direct 22
Memory indirect 17
Index 11
Assuming two cycles are consumed for an operand to be read from the memory,
one cycle for index arithmetic computations and zero cycles if operands are available in registers or with in instruction itself, the average operand fetch rate of the machine is-

24. A 1 ns cycles time unpipeline processor consumes 4 cycles for ALU operations,3 cycles for branches and 5 for memory operations. The relative frequencies of these operations are 45%, 15% and 40% respectively. What is the speedup in the instruction execution rate if the same were pipelined? Assume a 0.4 ns overhead consumed in setup and clock skew taken together.

25. the range of intigers that one can represent using an n bit 2s complement number system is
A. -2(n-1) to (2n-1)
B. -2(n-1) to (2(n-1)-1)
C. -2n to(2n-1)
D. -2n +1 to (2(n-1) -1)

26.The minimized function f obtained from the K-map given above is

27. The standard sum of products of the function f = A+Bc is expressed as-
A. ∑m(1, 4, 5, 6, 7) + d(0, 2, 3)
B. ∑m(1, 4, 5, 6, 7)
C. ∑m(0, 2, 3) + d(1, 4, 5, 6, 7)
D. ∏M (1, 4, 5, 6, 7)

28. hazards in combinational circuits are removed by-
A. Enclosing the minterms that cause the hazard with a product term that overlaps both groupings.
B. Using NOT gates at all inputs.
C. Using NOT gates at all outputs.
D. None of the above.

30. four D type flip flops are connected in such a manner that output Qi of one is connected to the D input of the next flip flop.the input to the initial D-flip flop is given by
D1 =Q3 XOR Q 4 Allflip flops are clocked synchronously. Which of the following statements is /are true?
i.D1 is ahead of Qi by one clock pulse.
ii.The circuit outputs the sequence 100010011010111 along all Qi s
A. Only (i) is true
B. Only (ii) is true
C. Both (i) and (ii) are true
D. None of the statement is true.

31. Three is NOT gates are cascaded and the out put of the third provides input to the first. Which of the following statements is true?
A. The connection from the output to the will lead to contention and hence damage the circuit on power on.
B. The output is unpredictable making the circuit useless.
C. The output will be uniformly held at either logic 0 and logic 1.
D. The out put will alternate between logic 0 and logic 1 continuously.

32. A certain device dumps data into its interface register every 200 ns. The main memory access time is 50 ns. If the CPU were interfaced to his device in cycle stealing mode, what percentage of time does the CPU be in hold state?
A. 20
B. 25
C. 50
D. None of these

33. If a disc has a rotation speed of R rpm and track storage capacity of C bits, the data transfer rate of the drive is defined as-
A. R/C bits/min
B. C/R bits/min
C. 0.5(R*C) bits/min
D. R*C bits/min

34. In the NONIX operating system, the time required for various file read operations are given below:
Disk seek time: 25 msec
Disk latency time: 8 msec
Disk transfer time: 1 msec/Kbyte
Operating system overheads: 1 mse/Kbyte + 10 msec.
What is the time required to retrieve a block of Kbytes?
A. 45 msec
B. 47 msec
C. 90 msec
D. 94 msec

35. Which of t he following page replacement method guarantee the minimum number of page faults?
A. Replace the page whose next reference will be the farthest in future.
B. Replace the page whose next reference will be the nearest in future.
C. Replace the page whose most recent reference was the nearest in past.
D. Replace the page whose most recent reference was the farthest in past

36. Which of the following statement is/are true about paging?
P: it divides memory into units of equal size.
Q: it permits implementation of virtual memory. R: it suffers from internal fragmentation.
A. P only
B. Q only
C. R only
D. P and Q only

37. The sequence of page addresses generated by program is 1, 2, 2, 1, 3, 4, 2, 1, 3, 4.
This program is run on a system with main memory size equal to 3 pages. Which pages are in the memory just before 5th page fault, if least recently used page replacement is followed?
A.1, 2, 3
B.1, 2, 4
C.1, 3, 4
D.2, 3, 4

38. Assume that the following jobs are to be executed on a single processor system.
Job id CPU burst time
1 3
2 4
3 5
4 1

Assume that the jobs are arrived at time 0* and in the 1, 2, 3, 4. for round robin scheduling with time slice 1, what is the completion time for the jobs 2?
A. 7
B. 8
C. 9
D. 11

39. Consider the following jobs given below:
Job id arrival time CPU time
1 0 4
2 3 7
3 7 4
4 1 1
What is the average turnaround time with non- preemptive shortest job first scheduling algorithm?
A. 2.75
B. 5.75
C. 6.5
D. 8.5

40. which of the following statement is /are TRUE about thrashing?
P: implies excessive page faults. Q: CPU utilization decreases
R: implies less page faults. A. P only
B. Q only
C. P and Q only
D. Q and R only

41. A computer system has 9 printers, with a processes competing for them. Each process needs 3 printers. What is the maximum value of n for the system to be deadlock free?

42. A counting semaphore was initialized to eight. Then four P (wait) operations and six V (signal) operations are performed on the semaphore. What is the resulting value of the semaphore?

43. A computer system uses the Bankers algorithm to deal with deadlocks its current state is shown in the table below, where P0, P1, P2 and P4 are processes and A, B, and C are resources types.

P0 6 5 4
P1 3 4 2
P2 1 0 4
P3 3 2 5

P0 0 3 4
P1 2 1 2
P2 0 0 2
P3 1 2 1


4 3 1

Which of t he following is/are safe sequences?
P: P1, P0, P2, P3
Q: P1, P2, P0, P3
R: P1, P3, P0, P4

A. P and Q only
B. P and R only
C. Q and R only
D. All P, Q and R.

44. Which of the following most appropriately describes the language generated by the grammer: S aSa| bSb | ε
A. The set of string over {a, b} that begin and end with the same symbol. B. The set of palindromes over {a, b}.
C. The set of string over {a, b}with equal number of as and bs.
D. The set of even length palindromes over {a, b}.
45. Consider the rule of the C programming language every variable must be declared before its use. in which of the following phase of the compiler will an error violating this rule be detected?
A. Code generation B. Lexical analysis C. Syntax analysis
D. Semantic analysis.

46. Find the best match between the element of Group-1 and Group -2 given below.
Group-1 Group -2
P. Dataflow analysis 1. Lexical analysis
Q: Regular expression 2. Semantic analysis
R: Type Checking 3.Parsing
S: Pushdown Automata 4. Code optimization

A. P-4, Q-1, R-3, S-2
B. P-2, Q-1, R-4, S-3
C. P-1, Q-4, R-2, S-3
D. P-4, Q-1, R-2, S-3

47. Consider the grammar: S L= R | R L * R | id R L
Which of the following set of LR (0) items definitely does not represent a valid state of an LR (0) parser?
A. S L =∙R, R ∙L B. L id.
C. S L∙ = R, R L∙
D. R L∙

48. Which of the following is/are true?
i.A left recursive grammar cannot be LL( 1 ).
ii.A right recursive gammar cannot be LR(1).
iii.Every grammar that can be parsed by a canonical LR parser can also be parser by some SLR parser.

A. I and II only
B. I only
C. II only
D. I,II and III

49. Consider a state of an LR ( 0) parser containing the following two items only.
A → abB∙
C → a∙b
Which of the following CAN NOT be deducted from the information provided above?
A. There is shift reference conflict in the parsing table. B. The given grammar is not LR(0).
C. There is reduce reference conflict in the parsing table.
D. The goto function for this state on symbol b must lead to some state.

50. Who developed the original version of SQL?
A. Oracle
C. mySQL AB D. Microsoft

51 For the relational schema RK1K2 are the only candidate keys. R has a functional dependency X A
where X is a set of attributes and A is an attribute. It is known that AK1 and AK2 and X is not a superkey. Which of the following is true?
A. R should be in BCNF.
B. R is not surely in BCNF, but could be in 3NF

C. R is not surely in 3NF, but could be in 2NF
D. R is not surely in 2NF, but could be in 1NF

52. R is a rational schema with the following functional dependencies.
A DC B A C E EBD

Which of the following is not a candidate key of R.

53. If the following elements are inserted in the given order into initially empty B+tree in which each node can hold at most 4 pointers,
what will be the number of leaf nodes in the B+ tree at the end of the insertions?
1 3 5 6 7 8 14 22 32 33 37

54. In the following, T1 and T2 are transactions and A is an object. Which of the following has the potential of making T2 irrecoverable?
A. T2 writes A after T1 wrote A; T1 is uncommitted
B. T2 reads A after T1 wrote A ; T1 is uncommitted
C. T2 writes A after T1 wrote A ; T1 is committed
D. T2 reads A after T1 wrote A; T1 is uncommitted

55. Which of the following is impossibility?
A. A sparse primary index
B. A sparse secondary index
C. A dense primary index
D. A dense secondary index

57.RDBMS Query
58.DBMS Query

59. Arrange the following functions in increasing asymptotic order
(P)√ (log2n) (Q)√ n (R) 2 (log2n / log2 log2n) /*power of 2(then log part) */ (S) log2 log2(n!)


60.Which of the following is false?
A) the aveg case time complexities of quick sort and heap sort are O(nlogn).
B) the worst case time complexities of quick sort and heap sort are O(n2).
C) the aveg case time complexities of merge sort and insertion sort are O(n2).
D) the worst case time complexities of quick sort and merge sort are O(nlogn).

61.Which of the following exemplifies Divide and conquer?
B)Insertion sort
C)Bubble sort
D)Merge sort.

62.Consider a sequence A of length n which is sorted except for one item that appears out of order.Which of the following can sort the sequence in O(n) time?
B)Quick sort
C)Merge sort
D)Insertion sort.

63.If T(n)= 3T(n/2)+n, if n>1. T(1)=1. Then T(n)=? A)Θ(n)
B) Θ(n (log23) ){ n to the power log23}
C)Θ(n 3/2)
D) Θ(n (log23) log2n

64.Let S1= ∑nr/2r (r=0 to logn-1) .S2= ∑r2r (r=0 to logn-1) Which of the following is true?
A)S1= Θ(nlogn),S2= Θ(nlogn)
B) S1= Θ(n),S2= Θ(nlogn)
C) S1= Θ(nlogn),S2= Θ(n)
D) S1= Θ(n),S2= Θ(n)

65.Question based on Dynamic programming with memorization. Complexity is asked for a function.
66. To remove recursion from a program we have to use the following data structure:
A. array
B stack
C queue
D list

67. Absence of terminating condition in a recursive program causes the following run time error:
A) array out of bounds
b) stack overflow
c) null ptr access
d) division by zero

68.On a set of n elements linear search is preferred over binary search when there are :
a)Ω(log n) queries
b) O(log2 n) queries
c) o(log n) queries
d) Θ(log2 n) queries

69.#include Void main() {
Int a=4,b=5,c=6; C+=a++ + ++b; Printf(a=%d,b=%d,c=%d, \n,a,b,c);
What is the o/p of the above c program:
a) 5 6 17
b) 56 18
c) 5 5 16
d) 5 6 16

70.what is the max size of the operator stack during the conversion of the infix exp A+B*C-D/E to postfix?

71. what is the max size of the operand stack while evaluating the postfix exp 6 2 3 + - 3 8 2 / + * ?

72. Binary search can be carried out on the set of ordered out on a set of ordered data items stored in a:
A. array
B stack
C queue
D list

73. To o/p a binary tree level by level we have to use the following data structure
A. array
B stack
C queue
D list

74. Which one of the following arrays satisfies max-heap property?
A) 16,10,12,8,3,5

75.The max number of comparisons required to sort 5 elements is
a) 4
B) 5
c) 6

76 The worst case time complexity of quicksort for n elements when the median is selected as the pivot element is :
a)Θ (n2)
b) O(n2)
c)Θ (n log n)
d) o( n log n)

77.The number of null links in a binary tree with n nodes is :
a) n-1 b) n
c) n+1 d) 2n

78.What is the max possible height of an AVL tree with 20 nodes ?
B) 5
c) 6

79.let T be a B-tree of order m and height h. If n is the no of key elements in T then the max value of n is :
a)(m-1) h-1
b)(m-1) h-1+1
C) m h-1
D) m h-1+1

80. Adjacency list is preferred over adjacency matrix when the graph is :
B) Dense
c) Clique
D) None of the above

81.A binary tree can be uniquely reconstructed from the following traversal(s):
A) preorder
B) postorder
c) preorder and postorder
d) inorder and preorder

82. In a simple connected undirected graph with n nodes (n>=2) the max number of nodes with distinct degrees is
a) n-1
c) n-3

83. The max number of edge disjoint cut sets in a simple graph with n nodes is:
a) n
b)2 n
84.If an undirected graph has Hamiltonian cycle then it is definitely :
a) tree
b) clique
c) Bi-connected
d) Tri-connected

85.If an undirected graph doesnt have an odd cycle , then it is:
d) clique

86. To color a cycle of length 9, max number of colors required is :
a)2 b)3 c)4 d)5

87.what is the number of edge disjoint Hamiltonian cycles in a complete graph G=(V,E), where |v|=n and n is odd?
b)┌ n/2 ┐
d) n 2

88. Given a set of n elements not all distinct, the majority element is one with freq>=n/2. So the majority elements is always the
A) max element
B) minimum element
C) mean element
D) median element

89.Let 01111 be the frame delimiter flag in a data link protocol. What is the transmitted bit sequence for the data 0111110111011110 using the bit stuffing method?

90. A frame 110010111001 is to be transmitted using the CRC with generating poly x3+x+1 to protect it from errors. What is the transmitted frame?

91.The distance between two microwave towers, with link capacity 100Mbps, is 24km and the speed of the signal is 3X108 m/s.
If the frame size is 16kb in the stop and wait protocol, what is the approx link utilization ? assume that the ack packets are negligible in size and there are no errors during comm..
D) 75%

92.Two ground stations r connected by a 10Mbps Sat link. The altitude of the satellite is 36000km and the speed of the signal is 3X108 m/s.
What shd be the packet size for the channel utilization of 50% using go-back-100 sliding window protocol? assume that the ack packets are negligible in size and there are no errors during comm..
a) 1.5Kbytes
b)3 Kbytes
c)4.5 Kbytes
d)6 Kbytes

93.Match the following
I data link layer
II network layer
Q. UDP III Transport layer
R. RARP IV App layer


94.The sound trip propagation delay for 100Mbps Ethernet having 48-bit jamming signal is 64 μs .What is the minimum frame size?
A) 400 bytes
B)600 bytes
C)800 bytes
D) 1400 bytes

95. Match the following
I 802.3 P. wireless LAN
II 802.11 Q. Bluetooth
III 802.15 R. Ethernet
IV 802.16 S. wireless MAN

a) I-R, II-P, III-Q ,IV-S
b) I-R, II-P, III-S ,IV-Q
c) I-R, II-Q, III-P ,IV-S
d) I-P, II-R, III-S ,IV-Q

96.Match the following

a) I-S, II-P, III-R ,IV-Q
b) I-S, II-R, III-Q ,IV-P
c) I-R, II-Q, III-S ,IV-P
d) I-S, II-Q, III-R ,IV-P

97. which of the following statements is/r true about datagram subnet? P: each packet contains the full source and destination addresses.
Q: Two packets b/n source and destination can follow diff. paths.
a) P only
b) Q only
c) Both P and Q
d) Neither P nor Q.

98.A computer on a 6Mbps network is regulated by a token bucket.The token bucket is filled at a rate of 2Mbps.It is initially filled to a full capacity of 8Mb.How long can the computer transmit at the full 6Mbps?
b)1.6 sec
c)1.9 sec

99.The routing table of a router is shown below

Destination Subnet mask interface Eth0 Eth1 Eth2 Eth3

A packet bearing a destination address arrives at router. On which interface will it be forwarded?

100.which of the following statements is /are True about IP address?
P: IP address is used for broadcasting on class B network.
Q: IP address is used for loopback testing.
A)P only
B)Q only
C)Both P and Q
D)Neither P nor Q.

DRDO Placement Paper : DRDO(CEPTAM) Placement Paper Electronics and electrical 01 Aug 2012

DRDO(Defence Research & Development Organisation) CEPTAM (Centre for Personnel Talent Management)

DRDO (CEPTAM)electronics and electrical Previous years Questions

1.The current I in the given network.
a) 1A

b) 3A

c) 5A

d) 7A

2.For the Delta- Wye transformation in given figure, the value of the resistance R is.
a) 1/3 ohms

b) 2/3 ohms

c) 3/2 ohms

d) 3 ohms

3.In the given network, the Thevenins equivalent as seen by the load resistance Rl is
a) V=10 V, R= 2ohms

b) V=10V, R=3 ohms

c) V=15V, R= 2ohms

d) V=15V, R=3 ohms

4.The current I in a series R-L circuit with R=10 ohms and L=20mH is given by i=2sin500t A. If v is the voltage across the R-L combination then i
a) lags v by 45 degree

b) is in-phase with v

c) leads v by 45

d) lags v by 90

5.In thr given network, the mesh current I and the input impedance seen by the 50 V source, respectively, are
a) 125/13 A and 11/8 ohms

b) 150/13 A and 13/8 ohms

c) 150/13 A and 11/8 ohms

d) 125/13 A and 13/8 ohms

6.A voltage sourcehaving a source impedance Z = R + jX can deliver maximum Average power to a load impedance Z, when
a) Z = R + jX

b) Z = R

c) Z = jX

d) Z = R jX

7.In the given circuit, the switch S is closed at t=0. Assuming that there is no initial Charge in the capacitor, the current i(t) for t>0 is
a) V/R e^ (-2t/RC)

b) V/R e^ (-t/RC)

c) V/2R e^ (-2t/RC)

d) V/2R e^ (-t/RC)

8.For the circuit in given figure, if e(t) is a ramp signal, the steady state value of the Output voltage v(t) is
a) 0 b) LC c) R/L d) RC

9.For the series RLC circuit in given figure, if w=1000 rad/sec, then the current I (in Amperes) is
a) 2 ∟-15

b) 2 ∟15

c) √2∟-15

d) √2∟15

10.The Y-parameter matrix (mA/V) of the two-port given network is
a) [2 -1 -1 2]

b) [2 1 -1 2]

c) [1 -2 -1 2]

d) [2 1 1 2]

11.The maximum number of trees of the given graph is
a) 16 b) 25 c) 100 d) 125

12.Given figure shows a graph and one of its trees. Corresponding to the tree, the group of branches that CAN NOT constitute a fundamental cut set is
a) 1,2,3

b) 1,4,6,8,3

c) 5,6,8,3

d) 4,6,7,3

13.The Y-parameter matrix of a network is given by Y=[1 1 -1 1] A/V. The Z11 parameter of the same network is
a) ohms

b) 1/√2 ohms

c) 1 ohms

d) 2 ohms

14.For the given circuit, the switch was kept closed for a long time before opening it at t=0. The voltage v(0+) is
a) -10 V b) -1 V c) 0V d) 10 V

15.The input impedance of a series RLC circuit operating at frequency W=√2w, w being the resonant frequency, is
a) R-j(wL/√2) ohms

b) R+j(wL/√2) ohms

c) R-j√2wL ohms

d) R-j√2wL ohms

16.The threshold voltage V is negative for
a) an n-channel enhancement MOSFET

b) an n-channel depletion MOSFET

c) an p-channel depletion MOSFET

d) an p-channel JFET

17.At a given temperature, a semiconductor with intrinsic carrier concentration ni= 10 ^ 16 / m^3 is doped with a donor dopant of concentration Nd = 10 ^ 26 /m^3. Temperature remaining the same, the hole concentration in the doped semiconductor is
a) 10 ^ 26 /m^3

b) 10 ^ 16 /m^3

c) 10 ^ 14 /m^3

d) 10 ^ 6 /m^3}

18.At room temperature, the diffusion and drift constants for holes in a P-type semiconductor were measured to be Dp = 10 cm^2/s and p = 1200 cm^2/V-s, respectively. If the diffusion constant of electrons in an N-type semiconductor at the same temperature is Dn = 20 cm^2/s, the drift constant for electrons in it is
a) n = 2400 cm^2/V-s

b) n = 1200 cm^2/V-s

c) n = 1000 cm^2/V-s

d) n = 600 cm^2/V-s

19.A common LED is made up of
a) intrinsic semiconductor

b) direct semiconductor

c) degenerate semiconductor

d) indirect semiconductor

20.When operating as a voltage regulator, the breakdown in a Zener diode occurs due to the
a) tunneling effect

b) avalanche breakdown

c) impact ionization

d) excess heating of the junction.

21.If the common base DC current gain of a BJT is 0.98, its common emitter DC current gain is
a) 51 b) 49 c) 1 d) 0.02

22.Negative resistance characteristics is exhibited by a
a) Zener diode

b) Schottky diode

c) photo diode

d) Tunnel diode

23.Let En and Ep, respectively, represent the effective Fermi levels for electrons and holes during current conduction in a semiconductor. For lasing to occur in a P-N junction of band-gap energy 1.2 eV, (En - Ep) should be
a) greater than 1.2eV

b) less than 1.2eV

c) equal to 1.1eV

d) equal to 0.7eV

24.In a P-well fabrication process, the substrate is
a) N-type semiconductor and is used to build P-channel MOSFET
b) P-type semiconductor and is used to build P-channel MOSFET
c) N-type semiconductor and is used to build N-channel MOSFET
d) P-type semiconductor and is used to build N-channel MOSFET

25.In a MOS capacitor with n-type silicon substrate, the Fermi potential = -0.41 V and the flat-band voltage Vfb = 0V. The value of the threshold voltage Vt is
a) -0.82 V b) -0.41 V c) 0.41 V d) 0.82

Refer given figure for question 26 and 27. Assume D1 and D2 to be ideal diodes.
26.Which one of the following statements is true?
a) Both D1 and D2 are ON.
b) Both D1 and D2 are OFF.
c) D1 is ON and D2 is OFF.
d) D2 is ON and D1 is OFF.

27.Values of Vo and I, respectively, are
a) 2V and 1.1 mA

b) 0V and 0 mA

c) -2V and 0.7 mA

d) 4V and 1.3 mA

28.In a BJT CASCODE pair, a
a) common emitter follows a common base
b) common base follows a common collector
c) common collector follows a common base
d) common base follows a common emitter

29.Inside a 741 op-amp, the last functional block is a
a) differential amplifier

b) level shifter

c) class-A power amplifier

d) class-AB power amplifier

30.For the MOSFET in the given circuit, the threshold voltage Vt = 0.5V, the process parameter KP = 150 A/V^2 and W/L = 10. The values of Vd and Id, respectively, are
a) Vd = 4.5 V and Id = 1 mA
b) Vd = 4.5 V and Id = 0.5 mA
c) Vd = 4.8 V and Id = 0.4 mA
d) Vd = 6 V and Id = 0 mA
31.A negative feedback is applied to an amplifier with the feedback voltage proportional to the output current. This feedback increases the
a) input impedance of the amplifier

b) output impedance of the amplifier

c) distortion in the amplifier

d) gain of the amplifier

32.The early effect in a BJT is modeled by the small signal parameter
a) r0 b) r∏ c) gm d) β

33.For a given filter order, which one of the following type of filters has the least amount of ripple both in pass-band and stop-band?
a) Chebyshev type I

b) Bessel

c) Chebyshev type II

d) Elliptic

34.For a practical feedback circuit to have sustained oscillation, the most appropriate value of the loop gain T is
a) 1 b) -1 c) -1.02 d) 1.02

35.Assume the op-amps in given figure to be ideal. If the input signal vi is a sinusoid of 2V peak-to-peak and with zero DC component, the output signal vo is a
a) sine wave

b) square wave

c) pulse train

d) triangular wave

36.In a common source amplifier, the mid-band voltage gain is 40 dB and the upper cutoff frequency is 150kHz. Assuming single pole approximation for the amplifier the unity gain frequency fT is
a) 6 MHz b) 15 MHz c) 150 MHz d) 1.5 GHz

37.An op-amp is ideal except for finite gain and CMRR. Given the open loop differential gain Ad=2000, CMRR = 1000, the input to the noninverting terminal is 5.002 V and the input to the inverting terminal is 4.999 V, the output voltage of the op-amp is

a) 14 V b) 24 V c) -6 V c) -8 V

38.The op-amp in the circuit in given figure has a non-zero DC offset. The steady state value of the output voltage Vo is
a) RC dvs(t)/ dt b) (1/RC)|vs(t)dt c) V d) +V

39.For the circuit in given figure, if the value of the capacitor C is doubled, the duty-cycle of the output waveform Vo
a) increases by a factor of 2

b) increases by a factor of 1.44

c) remains constant

d) decreases by a factor of 1.44

40.Assume the op-amp in the given circuit to be ideal. The value of the output voltage Vo is
a) 3.2 Vi b) 4 Vi c) 9 Vi d) 10 Vi

41.The complement of the Boolean expression F = (X + Y + Z)(X + Z)(X + Y) is




42.The Boolean function F(A,B,C,D) = ∑(0,6,8,13,14) with dont care conditions d(A,B,C,D) = ∑(2,4,10) can be simplified to
a) F = BD+CD+ABC




43.The Boolean function F = AD+BD can be realized by one of the following figures

44. For the multiplexer in given figure, the Boolean expression for the output Y is

45. Which one of the following is TRUE?
a) Both latch and flip-flop are edge triggered.
b) A latch is level triggered and a flip-flop is edge triggered.
c) A latch is edge triggered and a flip-flop is level triggered.
d) Both latch and flip-flop are level triggered.

46. In a schottky TTL gate, the Schottky diode
e) increases the propagation delay
f) increases the power consumption
g) prevents saturation of the output transistor
h) keeps the transistor in cutoff region

47. For which one of the following ultraviolet light is used to erase the stored contents

48. Which one of the following is NOT a synchronous counter
a) Johnson counter

b) Ring counter

c) Ripple counter

d) Up-down counter

49. In 8085 microprocessor, the accumulator is a
a) 4 bit register

b) 8 bit register

c) 16 bit register

d) 32 bit register

50. In the register indirect addressing mode of 8085 microprocessor, data is stored
a) at the address contained in the register pair
b) in the register pair
c) in the accumulator
d) in a fixed location of the memory

51. The output w[n] of the system shown in given figure is
a) x[n] b) x[n-1] c) x[n] x[n-1] d) 0.5(x[n-1] + x[n])

52. Which one of the following is a periodic signal
a) x(t) = 2 e^j(t+(π/4))

b) x[n] = u[n] + u[-n]

c) x[n] = ∑{∂[n-4k]-∂[n-1-4k]} where k = -∞to ∞

d) x(t) = e^ (-1+j)t

53. If the input-output relation of a system is y(t) = ∫x(t) dt where t = -∞ to 2t
a) linear, time-invariant and unstable
b) linear, non-causal and unstable
c) linear, causal and time invariant
d) non-causal, time invariant and unstable

54. Which one of the can be the magnitude of the transfer function | H(jw) | of a causal system

55. Consider the function H(jw) = H1(w) + jH2(w), where H1(w) is an odd function and H2(w) is an even function. The inverse Fourier transform of H(jw) is
a) a real and odd function
b) a complex function
c) a purely imaginary function
d) a purely imaginary and odd function

56. The laplace transform of given signal is
a) A((1-e^cs)/s)

b) A((1-e^cs)/s)

c) A((1-e^-cs)/s)

d) A((1-e^-cs)/s)

57. If X(z) is the z-transform of x[n] = (1/2)^ |n|, the ROC of X(z) is
a) |z| > 2 b) |z| < 2 c) 0.5<|z|<2 d) the entire z-plane

58. In a linear phase system, τg the group delay and τp the phase delay are
a) constant and equal to each other b) τg is a constant and τp is proportional to w c) a constant and τg is proportional to w d) τg is proportional to w and τp is proportional to w

59. A signal m(t), band-limited to a maximum frequency of 20 kHz is sampled at a frequency fs kHz to generate s(t). An ideal low pass filter having cut-off frequency 37 kHz is used to reconstruct m(t) from s(t). The maximum value of fs required to reconstruct m(t) without distortion is
a) 20 kHz

b) 40kHz

c) 57 kHz

d) 77 kHz

60. If the signal x(t) shown in given figure is fed to an LTI system having impulse response h(t) as shown in given figure, the value of the DC component present in the output y(t) is
a) 1 b) 2 c) 3 d) 4

61. The characteristic equation of an LTI system is given as s^3 + Ks^2 + 5s + 10. When the system is marginally stable, the value of K and the sustained oscillation frequency w, respectively, are
a) 2 and 5

b) 0.5 and √5

c) 0.5 and 5

d) 2 and √5

62. The time required for the response of a linear time-variant system to reach half the final value for the first time is
a) delay time

b) peak time

c) rise time

d) decay time

63. The signal flow graph of the given network is

64. Let c(t) be the unit step response of a system with transfer function K(s+a)/(s+K). If c(0+)=2 and c(∞)=10, then the values of a and K, respectively, are
a) 2 and 10

b) -2 and 10

c) 10 and 2

d) 2 and -10

65. The loop transfer function of an LTI system is G(s)H(s)= K(s+1)(s+5) / s(s+2)(s+3). For K>0, the point on the real axis that DOES NOT belong to the root locus of the system is
a) -0.5 b) -2.5 c) -3.5 d) -5.5

66. The state space equation of the circuit shown in given figure for x1=v0, x2=I is

67. The open loop gain of a unity feedback system is G(s)=wn^2 / s(s+2wn). The unit step response c(t) of the system is

69. The angles of the asymptotes of the root loci of the equation s^3 + 5s^2 + (K+2)s + K = 0, for 0<=K<∞, are
a) 0 and 270

b) 0 and 180

c) 90 and 270

d) 90 and 180

70. The bode plot corresponding to a proportional derivative controller is the one shown in given figure

71. In frequency modulation, the instantaneous
a) amplitude of the carrier signal is varied with the instantaneous amplitude of the message signal
b) amplitude of the carrier signal is varied with the instantaneous frequency of the message signal
c) frequency of the carrier signal is varied with the instantaneous amplitude of the message signal
d) frequency of the carrier signal is varied with the instantaneous frequency of the message signal

72. If X is a zero mean Gaussian random variable, then P{X<=0} is
a) 0 b) 0.25 c) 0.5 d) 1

73. If a single-tone amplitude modulated signal at a modulation depth of 100% transmits a total power of 15W, the power in the carrier component is
a) 5W b) 10W c) 12W d) 15W

74. In a superheterodyne receiver, rejection of the image signal can be achieved by using a
a) higher local oscillatorn frequency b) crystal oscillator c) narrow band IF filter d) narrow band filter at RF stage

75. The number of bbits per sample of a PCM system depends upon the
a) sampler type b) quantizer type c) number of levels of the quantizer d) sampling rate

76. Which one of the following is used for the detection of AM-DSB-SC signal
a) Ratio detector b) Foster-Seeley discriminator c) Product demodulator d) Balanced-slpoe detector

77. Which one of the following signal pairs can represent a BPSK signal
a) A cos2πfct, A sinπfct
b) A cos2πfct, - A sinπfct
c) - A cos2πfct, A sinπfct
d) A sin2πfct, A cosπfct

78. Which one of the following can be used for the detection of the noncoherent BPSK signal
a) matched filter b) phase-locked loop c) envelope detector
d) product demodulator

79. Bits of duration Tb are to be transmitted using a BPSK modulation with a carrier of frequency Fc Hz. The power spectral density of the transmitted signal has the first null at the normalized frequency
a) |F Fc|Tb = 0 b) |F Fc|Tb = 1 c) |F Fc|Tb = 2 d) |F Fc|Tb = 4

80. The probability of bit error of a BPSK modulation scheme, with transmitted signal energy per bit Eb, in an additive white Gaussian noise channel having one-sided power spectral density N0, is
a) (1/2) erfc(Eb/2N0) b) (1/2) erfc√(Eb/2N0) c) (1/2) erfc(Eb/N0) d) (1/2) erfc√ (Eb/N0)

81. For a given transmitted pulse p(t), 0<=t<=T, the impulse response of a filter matched to the received signal is
a) p(t-T), 0<=t<=T b) p(T-t), 0<=t<=T c) p(t-T), 0<=t<=T d) p(T-t), 0<=t<=T

82. The multiple access communication scheme in which each user is allocated the full available channel spectrum for a specified duration of time is known as

83. GSM system uses TDMA with
a) 32 users per channel b) 16 users per channel c) 8 users per channel d) 4 users per channel

84. If Rx(τ) is the auto-correlation function of a zero-mean wide-sense stationary random process X, then which one of the following is NOT true?
a) Rx(τ) = Rx(-τ) b) Rx(τ) = -Rx(-τ) c) σx^2 = Rx(0) d) |Rx(τ)| <=Rx(0)

85. If E denotes the expectation operator, then E[X-EX]^3 of a random variable X is
a) EX^3 E^3X b) EX^3 + 2E^3X 3EX Ex^2 c) 3EX^3 E^3X d) 2EX^3 + E^3X 3EX EX^2

86. A discrete memoryless source produces symbols m1,m2,m3 and m4 with probabilities 1/2, 1/4 , 1/8 and 1/8, respectively. The entropy of the source is
a) b) 1 c) 7/4 d) 2

87. A channel has a signal-to-noise ratio of 63 and bandwidth of 1200 Hz. The maximum data rate that can be sent through the channel with arbitrary low probability of error is
a) 600 bps b) 1200 bps c) 4800 bps d) 7200 bps

88. For the vectors A = X ax + Y ay and B = Z az, del . (A X B) is
a) 0 b) 1 c) XZ d) YZ

89. Which one of the following relations represents Strokes theorem (symbols have their usual meaning)?
a) ∫s del X A.ds = 0 b) ∫L A.dl = ∫s del X A.ds c) ∫s A X dS = -∫v (del X A)dv d) ∫v del.Adv = ∫s A.ds

90. Which one of the following relations is not correct (symbols have their usual meaning)?
a) del X E = - ∂B/∂t b) del X H = J + ∂E/∂t c) del.D = ρv d) del.B = 0

91. The electric field component of a uniform plane wave propagating in a lossless magnetic dielectric medium is given by E(t,z)=ax 5cos(10^9 t 20/3 z)V/m. If η0 represents the intrinsic impedance of the free space, the corresponding magnetic field component is given by
a) H(t,z)= ay 5/2 η0 cos(10^9t 20/3 z)A/m
b) H(t,z)= ay 10/ η0 cos(10^9t 20/3 z)A/m
c) H(t,z)= az 5/2 η0 cos(10^9t 20/3 z)A/m
d) H(t,z)= az 10/ η0 cos(10^9t 20/3 z)A/m

92. The skin depth of a non-magnetic conducting material at 100 MHz is 0.15 mm. The distance which a plane wave of frequency 10 GHz travels in this material before its amplitude reduces by a factor of e^-1 is
a) 0.0015 mm b) 0.015 mm c) 0.15 mm d) 1.5 mm

93. A lossless transmission line has a characteristic impedance of 100 ohms and an inductance per unit length of 1 μH/m. If the line is operated at 1 GHz, the propagation constant β is
a) 2π rad/m b) 20π/3 rad/m c) 20π rad/m d) 2π *10^5 rad/m

94. When a load resistance Rl is connected to a lossless transmission line of characteristic impedance 75 ohms, it results in a VSWR of 2. The load resistance is
a) 100 ohms b) 75√2 ohms c) 120 ohms d) 150 ohms

95. A two-port network characterized by the S-parameter matrix, [S] = [0.3 L0 0.9 L90

0.9 L90 0.2 L0] Is

a) both reciprocal and lossless

b) reciprocal, but not lossless

c) lossless, but not reciprocal

d) neither reciprocal nor lossless

96. A lossless air filled rectangular waveguide has internal dimensions of a cm * b cm. If a=2b and the cutoff frequency of the TE02 mode is 12 GHz, the cutoff frequency of the dominant mode is
a) 1 GHz b) 3 GHz c) 6 GHz d) 9 GHz

97. A Hertzian dipole antenna is placed at the origin of a coordinate system and it is oriented along z-axis. In which one of the following planes the radiation pattern of the antenna has a circular shape?
a) x=0 b) y=0 c) z=0 d) =45

98. Which one of the following statements is not true?
a) Antenna losses are taken into account in calculating its power gain
b) For an antenna which does not dissipate any power, the directive gain and the power gain are equal
c) Directivity of an antenna is the maximum value of its directive gain
d) The directive gain of a Hertzian dipole is same in all direction

99. The directivity of a half dipole antenna is
a) 1.0 b) 1.5 c) 1.64 d) 2

100. Which one of the following is not true for a step index optical fibre?
a) It can support multiple modes
b) HE11 mode is its lowest order mode
c) The refractive index of the cladding is higher than that of the core
d) At a given wavelength, single mode operation is possible by proper choice of core diameter, core and cladding refractive indices.


101. Sarnath is situated in the state of
a) MP b) Bihar c) Punjab d) UP

102. Green house effect is due to the increase of atmospheric
a) CO2 level b) SO2 level c) CO level d) N2 level

103. In the month of July, it is winter in
a) New York b) Beijing c) Sydney d) London

104. The chairman of the Planning commission of India is
a) The prime minister b) The vice-president c) The union finance minister d) The union commerce minister

105. The satellite launch vehicle that placed a number of satellites ito orbit in May 2008 is
a) PSLV-C7 b) PSLV-C8 c) PSLV-C9 d) PSLV-C10

106.DRDO was formed in
a) 1947 b) 1950 c) 1954 d) 1958

107. SAMYUKTA is developed for the use of
a) Navy b) Army c) Air force d) RAC

108. DARL 202 is a variety of
a) pea b) garlic c) capsicum d) tomato

109. TRISHUL is
a) a surface to surface battlefield missile
b) a quick reaction surface to air missile
c) an intermediate range ballistic missile
d) a supersonic cruise missile

110. HUMSA is a
a) sonar b) tank c) mine d) night vision device

111. The value of 1+2i / 3-4i + 2-I / 5i , where i^2 is -1, is
a) -5/2 b) 5/2 c) 2/5 d) -2/5

112. The particular solution of the differential equation d^2y/dx^2 + 2 dy/dx + 5y = 0 satisfying the conditions y(0)=0 and y(0)=1 is
a) y=1/2 e^-x cos2x b) y=1/2 e^-x sin4x c) y=1/2 e^-x sin2x d) y=1/2 e^-x cos4x

113. For the vectors A=3i-2j+k and B=2i-k, the value of (A*B).A is
a) 0 b) 1 c) 2 d) 3

114. The orthogonal trajectory of the family of curves x^2-y^2 = a (where a is a constant) and passing through the point (1,1) is
a) y=-1/x b) y=1/x c) y=-x d) y=x
115. The value of the line integral ∫ y^2 dx + 2xydy over the curve x=accost, y=asint is
a) 0 b) 1 c) 2 d) 4

116. The n-th partial sum of the infinite series 1/1*2 + 1/2*3 + 1/3*4+1/n*(n+1)..
a) 1/n+1 b) n+2/n+1 c) n/n+1 d) n-1/n+1

117. The complex-valued function f(z)=e^z is analytic for
a) no z b) all z c) real z only d) imaginary z only
118. The inverse of the matrix [ cos A sin A
-sin A cos A] is

a) [ -cos A Sin A b) [cos A sin A} c) [cos A -sin A d) [cos A -sin A
sin A cos A] sin A -cos A] -sin A cos A] sin A cos A]

119. Consider the function f(x) defined as
F(x) = 3x-1, x<0
0, x=0
2x+5, x>0
In the following table, List I shows 4 expressions for limits of f(x) and List II indicates the values of the limits
List I List II
P.Lim x->2 f(x) 1. -1
Q.Lim x->0+ f(x) 2. 9
R.Lim x->0- f(x) 3. -10
S.Lim x->-3 f(x) 4. 5
The correct matches are
a) P-2,Q-4,R-1,S-3 B) P-2,Q-4,R-3,S-1 C) P-4,Q-2,R-1,S-3 D) P-4,Q-2,R-3,S-1

120. Two events A and B with probability 0.5 and 0.7, respectively, have joint probability of 0.4. The probability that neither A nor B happens is
a) 0.2 b) 0.4 c) 0.6 d) 0.8

121. Consider the differential equation
X^2 d^2/dx^2 + x dy/dx + (x^2 - 4)y = 0. The statement which is not true for it is
a) It is a linear second order ordinary differential equation
b) It can not be reduced to a differential equation with constant coefficients
c) X=0 is a regular singular point
d) It is a non-homogeneous second order ordinary differential equation

122. The sum of two numbers is 16 and the sum of their squares is a minimum. The two numbers are
a) 10,6 b) 9,7 c) 8,8 d) 5,11

123. The value of the definite integral 0∫(π/2)^(1/3) x^2 sin(x^3)dx is
a) -1/3 b) 0 c) 1 d) 1/3

124. A circle C2 is concentric with the circle C1 : x^2 + y^2 -4x +6y -12 =0 and has a radius twice that of C1. The equation of the circle C2 is
a) x^2 + y^2 -4x +6y -13 =0 b) x^2 + y^2 -4x +6y -87 =0 c) x^2 + y^2 -4x +6y -100 =0 d) x^2 + y^2 -4x +6y -88 =0

125. Consider the quadratic equation x^2 + px + q =0. If p and q are roots of the equation, the values of p and q are
a) p=0, q=0 only b) p=1, q=-2 only c) p=0, q=0 and p=1, q=-2 d) p=0, q=0 and p=-2, q=1

126. Consider the list of words: etiquette, accommodate, forty, exaggerate, continous, independent, receipt. The number of misspelt words are
a) 1 b) 2 c) 3 d) 4

127. Consider the following sentences
1. A few friends he has are all very rich.
2. Do not insult the weak.
3. The later of the two persons was more interesting.
4. All the informations were correct.
Out of these sentences, the grammatically correct sentence is
a) 1 b) 2 c) 3 d) 4

128. The appropriate auxiliary verb to fill in the blank of the sentence Gandhi knew that he __ soon be
a) would b) will c) shall d) may

129. The number of missing punctuation marks in the sentence Rajesh along with Amit went to the
a) 0 b) 1 c) 2 d) 3

130. The meaning of the word PLAGIARISM is
a) theft of public money b) theft of ideas c) belief in one god d) belief in many gods

132. ACROPHOBIA is the abnormal fear of
a) open spaces b) height c) fire d) water

133. The appropriate pair of prepositions to fill in the blank in the sentence He was angry __ me, because my remarks were aimed __
a) at,to b) with, at c) with, to d) at, for

134. The appropriate word(s) to fill up the blank in the sentence I remember __ voices in the middle of the (are)
a) hear b) to hear c) hearing d) heard

135. The passive voice form of the sentence I have known him for a long
a) He is known to me for a long time.
b) He is known by me for a long time.
c) He has been known to me for a long time.
d) He has been known by me for a long time.

136. If kennel is to a dog, then __ is to a hen.
a) nest b) coop c) hole d) stable

137. If NATION is to 5236765, then NOTION is to
a) 573675 b) 563765 c) 576375 d) 557365

138. The next two numbers of the series 3,5,11,21 are
a) 34 and 52 b) 34 and 53 c) 35 and 52 d) 35 and 53

139. A, B and C are three places in India with longitudes 80E, 85 E and 90 E respectively. Which one of the following statements about the local times of the places is true?
a) Local time of C is ahead of that of B.
b) Local time of B is ahead of that of C.
c) Local time of A is ahead of that of C.
d) A, B and C all have the same local time.

140. In this question, notations +, / and * are used as follows
A + B means A is the husband of B.
A / B means A is the sister of B.
A * B means A is the son of B.
With these relations, the relationship
denoted by P / Q * R is
a) P is son of R
b) P is daughter of R
c) P is uncle of R
d) P is father of R

141. If DELHI is written as EDHIL, then PARIS is written as

142. The number of prime numbers between 10 and 50 is
a) 10 b) 11 c) 12 d) 13

143. The odd one in the list : LAN, TCP/IP, HACKER and KILLER is

144. SAW is to carpenter as SCALPEL is to
a) surgeon b) mason c) plumber d) tailor

DRDO Placement Paper : DRDO(CEPTAM) Placement Paper Mental Ability Questions 01 Aug 2012

MENTAL ABILITY Questions DRDO(Defence Research & Development Organisation) CEPTAM (Centre for Personnel Talent Management)
Q.1) There are 40 coins in a bag, consisting of Rs. 5 and Rs. 2 coins. If the total amount is Rs. 140, how many Rs. 2 and Rs. 5 coins are there in the bag?
(1) 20 each -Answer
(2) 25 and 15
(3) 30 and 10
(4) 22 and 18

Q.2) 6(3 x) 5 (2x 4) = 4(3x) + 14 In the above equation the value of x is:
(1) 3
(2) 2
(3) 1 (4) -Answer

Q.3) The first Indian Governor of the RBI was:
(1) L.K.Jha
(2) C.D.Deshmukh -Answer
(3) I.G.Patel
(4) None of these

Q.4) X walked 35 metres towards South, then turned left and walked 25 metres, and again turned left and walked for 35 meters. He then turned to his right and walked 20 metres. At what distance and
direction from the starting point is X now standing?
(1) 20m West
(2) 45m East -Answer
(3) 20m East
(4) 45m North


Q.5) The sum of the interior angles of a polygon is twice the sum of its exterior angles. How many sides
does the polygon have?
(1) 8 sides -Answer
(2) 9 sides
(3) 12 sides
(4) 6 sides


Q.6) Sam said to Rita Your mohters husbands sister is my aunt. How is Rita related to Sam?
(1) Daughter
(2) Niece
(3) Sister -Answer
(4) Mother

Q.7) Four years ago, the average age of A and B was 18 years. At present the average age of A, Ba nd C is 24 years. What would be the age of C after 8 years?
(1) 30 years -Answer
(2) 32 years
(3) 28 years
(4) 25 years

Q.8) Unscramble the letters of words and find odd one out:
(1) ORNI
(2) ICAO
(4) ZENRBO -Answer

Q.9) Which is the greatest five digit number exactly divisible by 279?
(1) 99603
(2) 99882 -Answer
(3) 99550
(4) None of these


Q.10) Oranges are bought at 5 for Rs. 10 and sold at 6 for Rs. 15. The profit or loss as percentage is:
(1) 50%
(2) 40%
(3) 35%
(4) 25% -Answer

Q.11) Which country has won the cricket world cup maximum number of times?
(1) West Indies
(2) Pakistan
(3) Sri Lanka
(4) Australia

Q.12) Which of the given Venn diagrams out of 1, 2, 3 or 4 correctly illustrates the relationship among the following classes?
Reptiles, Cobras, Turtles. (2)
Q.13) Express 19992111 is decimal:
(1) 0.946-Answer
(2) 0.904
(3) 0.893
(4) 0.981

Q.14) The marks obtained by 10 students in Science (out of 50) are 30, 41, 40, 41, 30, 41, 30, 28, 41, 40.
The modal mark is:
(1) 40
(2) 30
(3) 41 -Answer
(4) 35

Q.15) 6, 18, 24, 9, 27, 33, 11?, ?
(1) 15, 19
(2) 22, 27
(3) 33, 39-Answer
(4) 44, 47

Q.16) Which of the Venn diagrams relationship among the following classes?
Cars, Scooters, Red.
(1) (2) (3) (4)

Q.17) X gives1/2 of his property to his wife and 1/2 of the rest of his son. The remainder is divided equally to his two daughters. The share of each daughter is:
(1) 1/8(2)
(2) 1/6
(3) 1/4
(4) 2/3

Q.18) Karenge ya Marenge (Do or Die) was the slogan of which movement in India?
(1) The Quit India Movement, 1921 -Answer
(2) Salt Movement, 1930
(3) Non-Cooperation Movement, 1921
(4) Indigo revolt, 1859-60

Q.19) Xerophytes live predominantly in:
(1) Ponds
(2) Mountains
(3) Deserts -Answer
(4) Brackish water
Q.20) The area of the base of a right cone is 154 m2and its volume is 308 m2The height of the cone is:
(1) 8 m
(2) 6 m -Answer
(3) 7 m
(4) 9 m

Q.21) The L.C.M. of two numbers is 12 times their H.C.F.. The sum of the H.C.F. and L.C.M. is 403. If one number is 93, then the other number is:
(1) 134
(2) 124 -Answer
(3) 128
(4) 310

Q.22) Jamshedpur is located on the bank of:
(1) Damodar
(2) Ganges
(3) Subarnarekha -Answer
(4) Musi

Q.23) The wages of 10 workers for a six-day week is Rs. 1200. What are the one days wages of 4 workers?
(1) Rs. 40
(2) Rs. 32
(3) Rs. 80 -Answer
(4) Rs. 24

Q.24) All natural numbers and 0 are called the _______ numbers.
(1) whole -Answer
(2) prime
(3) integer
(4) rational

Q.25) Judge : Justice : Censor: ?
(1) Freedom
(2) Morality
(3) Entertainment -Answer
(4) Halls

DRDO Placement Paper : DRDO(CEPTAM) Placement Paper (CEPTAM) General Science Question Paper 01 Aug 2012

DRDO(Defence Research & Development Organisation) CEPTAM (Centre for Personnel Talent Management)General science Questions
1. How many carbon atoms are there in one molecule of methane (chemical formula CH4?)
a. 1-Answer
b. 4
c. 5
d. The number cannot be determined from the formula.

2. Which form of matter has a definite volume, but no definite shape?
a. Solid
b. Liquid-Answer
c. Gas
d. Plasma

h3. Processes of changing a liquid to a gas is called
a. Melting
b. Boiling
c. Vaporization-Answer
d. Sublimation

4. An element is determined by the number of
a. Atoms
b. Electrons
c. Neutrons
d. Protons-Answer

5. Fluorine F is a
a. Metal
b. Non metal-Answer
c. Compound
d. Element

6. State of uranium (U) at 0? c and 1 atm of pressure is
a. Gas
b. Liquid
c. Solid-Answer
d. Vapour

7. CaSo4 is named as
a. Calcium carbonate
b. Calcium hydroxide
c. Calcium oxide
d. Calcium sulphate-Answer

8. Cobalt is a
a. Halogen
b. Transition metal-Answer
c. Alkaline earth metal
d. None of these

9. What term describes the concentration of a solution in moles per litter?
a. Molarity-Answer
b. Osmosis
c. Molality
d. Diffusion

10. The Ideal gas law is a combination of Boyles law, Charles law and Avogadros law .What is the Ideal gas law?
a. PV=NRT-Answer
b. PE=mgh
c. F=ma
d. V=IR

11. Which of these values signifies the greatest temperature?
a. 1 degree Kelvin
b. 1 degree Rankin
c. 1 degree Fahrenheit
d. 1 degree Celsius-Answer

12. What is the abbreviation THEL stands for
a. Tactical high energy laser-Answer
b. Titanium harmonic emergent laser
c. Thermabaric harmonic emergent light
d. Thermo baric high energy light

13. Why are recoilless guns recoilless?
a. Their barrels are open at both ends.-Answer
b. They are loaded with missiles not cannon balls
c. They are not placed an wheels
d. They are made up of very heavy metal

14. Which statement is true about airplanes?
a. To dive, ailerons are down
b. To dive, elevators are down-Answer
c. To dive, elevators are up
d. To dive, ailerons are up

15. Taxonomy of vertebrate divides fishes in to which two basic groups?
a. Jawed and jawless-Answer
b. Gilled and non-gilled
c. Mammalian and non-mammalian
d. Nematodes and non-nematodes

16. What makes almost 99% of the visible Universe?
a. Quasars
b. Nitrogen
c. Plasma-Answer
d. Solids

17. What do we call cells with a nucleus?
a. Prokaryotic
b. Eukaryotic-Answer
c. Mitochondrial
d. Golgi

18. What does the prefix achy- means?
a. Too fast-Answer
b. Too slow
c. Too loud
d. Too soft

19. A doctor says you need a CBC.What is he talking about?
a. An enema
b. A vacation
c. A medication
d. A blood test-Answer

20. In preparation for a blood test, the lab slip says you have to be NPO for 8 hours prior to test, what do you have to do?
a. Sleep for 8 hours
b. Exercise for 8 hours
c. Lie flat in bed for 8 hours
d. Do not take anything by mouth-Answer

21. What is the exact value of the `Pi?
a. 3
b. 22/7
c. Impossible to calculate-Answer
d. 3.14

22. What is the smallest prime number?
a. 2-Answer
b. 144
c. 1
d. 3

23. What is the only number with no reciprocal?
a. Pi
b. 0-Answer
c. 1
d. -1

24. How fast is a mile a minute?
a. Speed of the fastest human runner
b. 60 yards an hour
c. 60 kilometre an hour
d. 60 miles an hour-Answer

25. Yhrium
a. xe
b. Y-Answer
c. V
d. W

DRDO Placement Paper : DRDO Whole Testpaper


Hi  Many questions will be asked about your B.Tech Project

Device density on a processor/chip
Difference between computer and super computer
How the performance of a super computer is measured (in tera flops)
what is tera flop ?
If a 2.8GHz processor is given, calculate the number of floating point calculations that it can do.
name of indigenous super coputer (PARAM, built by C-DAC)
Did DRDO make any super computer ?

what is multi tasking
Question on Process serialization
Question on Producer consumer problem
Question on Inter Process Communication
Define critical section
Are Metal Oxide Semiconducter devices slower ? Why ?

Truth table of half adder & full adder
Question on Circular Queue
2/3 Questions on Binary search algorithm
Question in C about Strucuter & Union


DRDO Placement Paper : DRDO General - other


1) Coldest planet:Pluto
2) INS Shivali is the first:
3) Which one of the following was NOT indegineously developed?:Prithvi/Akash/Agni
4) Full form of SARS
5) Anthrax is a :Virus/Bacteria/.../...
6) Dakshina Gangothri is:Ganga,s origin/Indian camp @ antartica/.../...
7) Which of the following is a chemical weapon:Mustard Gas/Marsh Gas/.../...
8) A question based on Coding and Decoding
9) Another question similar to above
10) Question on series completion
11) Another series completion question
12) Where is Institute of Forensic Science?:Hyderabad
13) A G.K question based on X and Y chromosomes in males and females

Sample technical questions asked in test last year in CSE :

1) Banker,s algorithm is used for: Deadlock Avoidance
2) A LOT of questions were based on generating strings from a given grammar. 
3) A circle(dot) shown in the PCB is:Vcc/Grnd/Pin 1/Pin 14
4) Program Segment Prefix in MS-DOS 5.0 is:
5) Some IP addresses were given and the question was to select the private addess from it(?)
6) 10Base2 and 10Base5 wires refers to:
7) A question on sliding-window protocol
8) Which of the following require a driver?:disk/cache/ram/cpu
9) A LOT of mathematical questions which were asked from calculus,trigonometry...

The questions asked in ECE were mainly from Control Systems, Communications

EMT and microprocessor
Make sure that u know the fundas of microprocessors useful in interview also: see if u know these questions
1. Which type of architecture 8085 has? 
2. How many memory locations can be addressed by a microprocessor with 14 address lines? 
3. 8085 is how many bit microprocessor? 
4. Why is data bus bi-directional? 
5. What is the function of accumulator? 
6. What is flag, bus? 
7. What are tri-state devices and why they are essential in a bus oriented system? 
8. Why are program counter and stack pointer 16-bit registers? 
9. What does it mean by embedded system
10. What are the different addressing modes in 8085? 
11.What is the difference between MOV and MVI? 
12. What are the functions of RIM, SIM, IN? 
13. What is the immediate addressing mode? 
14. What are the different flags in 8085? 
15. What happens during DMA transfer? 
16. What do you mean by wait state? What is its need? 
17. What is PSW? 
18. What is ALE? Explain the functions of ALE in 8085. 
19. What is a program counter? What is its use? 
20. What is an interrupt? 
21. Which line will be activated when an output device require attention from CPU? 
Then comes the interview questions asked in ECE interview were fundamental.Qustions asked in my interview were:

1. Which college and university are you coming from?
2. Did you appear for GATE? Why are you not interested in higher studies?
3. Did you appear for IES?
4. Did you appear for any other board interview of public sector?
5. The subjects you have learned in college can be divided into three- basic electronics, communi-cation and digital logic. Tell me any five subjects you like.
(I told radar and navigational aids, electronic warfare, satellite communication, biomedical instrumentation, fuzzy electronics and basic digital electronics as my subjects)

Board member1 (QUESTION LEVEL- MODERATE)                

1. Write the truth table for full adder and implement it in NAND gate only.
2. What,s the difference between looping 0s and 1s in K map?
3. Difference between microprocessor and micro controller
4. Microprocessors you are familiar with
5. How will you send and receive data to a micro-processor? (One method is I/O mapped I/O which is the other one?)
6. Radar range equation?
7. Does the radar range depend upon the frequency of the signal transmitted?
8. What is Doppler shift? What is its importance?


1. I will make two fuzzy statements. Pencil is long. Table is long. What is the term long signify?
2. What is a membership function?
3. What are the design criteria for very low frequency amplifier?
4. Can you measure distance with the help of CW radar? If so how?
5. How will you design a stable oscillator? (Not with crystal oscillator because temperature affects it)
6. You have designed an amplifier. After few days it is found that its gain have changed. What might be the reason?                          


1. A plane is moving in a circular path around the transmitter of the radar. Will there be Doppler shift detected in the radar?
2. State Keplers laws
3. Why there is more geo synchronous satellite?
4. The angular difference between two satellites is 2 degree. What is the maximum number of satellites needed to cover the whole earth?
5. What is the minimum number of satellites needed to cover the whole earth?


1. Which is the law of conservation involved in the second of Keplers?
2. Why do you explain elliptical orbit while stating Kepler,s law? Why not circular orbit?
3. What are the advantages of optical communication?
4. What are the invasive and non-invasive methods of instrumentation?

For CS guys they started with this question: What is a key board? Where u will connec? What will happen if you press the keys?..
For maths guys they asked some questions on series.. I don,t know muchSome guys were selected just by describing the final year project.    

1. How can you design a phase detector using a XOR gate? 
2. Questions abt differentiator and integrator. What will happen if we increase/decrease the values of R/C? 
3. how will a low/high pass filters behave to different signals ramp, pulse etc 
4. questions on flip flops 
5. Johnson counter 
6. Questions on microprocessors- what is SIM? 
7. Abt your project. What will happen when this/that happens to your project? 
8. Radar, antenna and satellite communication. 
9. Which is the first/latest communication satellite? 
10. What is apogee /perigee?

DRDO Placement Paper : DRDO Aptitude - General 3

DRDO Sample Questions

It contained 2 parts PART 1 - pure technical 100 ques. and Part 2 50 Ques.
Part 1 was purely technical but I was hard 2 answer part 2 general Knowledge abt 20-25ques were from maths remaining from general.They collected the question paper back. Iam herewith attaching some of the questions that  noted down at hall.

  1. If 100ns is Memory Access Time & 125 microsec is 1frame period. The no. of line that

    can be supported in a Time Divison Switch is

    a)125 Lines

    b)625 Lines

    c)525 Lines

    d)465 Lines

  2. The no. of edjes in disjoint Hamilton circuit in a complex graph with 17 edges is

    a) 8

    b) 9

    c) 136

    d) 17^2

  3. 15 persons in a club sit every day ina dinner table such that every member has different

    neighbour. This arrangement will last for how many days.  

    Assume a system has 16MB cache mean Disk Access Time & cache Access time is 76.5

    ns & 1.5 overall mean Access time us 465ms for each tripling the memory the miss rate is

    halved. The memory required to bring down the mean Access time to 24ns is

    a) 16 MB

    b) 24 MB

    c) 32 MB

    d) 48 MB

  4. Average transfer speed of a i/p serial line is minimum 25,000 Bytes & maximum 60000

    Bytes. Polling Strategy adopted takes 4microsec(whether there is any i/p byte or not). It is

    assured that byte that retrived from controller before next byte arrives are lost. Then the

    maximum safe polling interveal is

    a) 12

    b) 12.33

    c) 12.67

    d) 32

  5. A harddisk has a rotation speed of 4500RPM. then the latency time is

    a) .4

    b) .6

    c) .7

    d) .9

  6. Suppose all elements above the principal diagonal od n x n matix A are zero. If non zero

    elements of the lower triangular Matrix is stored in an array B with A[1][1] stored at

    B[1]. The addressing formula to the nonzero element in A[i][j]=?

    a) A[i][j]

    b) i(j-1)/2 +i

    c) j(i-1)/2 +i

    d) i(i-1)/2 +j

  7. The minumum number of comparisons requied to find the second smallest element in a

    1000 element array is

    a) 1008

    b) 1010

    c) 1999

    d) 2000

  8. The internal path length of a Bonary Tree with 10nodes is 25. The external path length is

    a) 25

    b) 35

    c) 40

    d) 45

  9. Average No. of Comparisons required to sort 3 elements is

    a) 2

    b) 2.33

    c) 2.67

    d) 3

  10. In a switch the mean arrival rate of packets is 800 Packets/sec and the the mean service

    rate is 925 Packets/sec

    a) .008 Sec

    b) .08 sec

    c) .8 sec

    d) 1.1 sec

  11. What is Interface Control Information?

  12. The minumum no. of Multiplications needed to compute x^768 is

    a) 9

    b) 10

    c) 425

    d) 767

  13. Find values for a,b,c,d

    c 1 1 1

    0 a 1 b


    1 0 d 0

    (967)basex = 321base9

    PART II Genreal 50 General Non-Technical[4 Options]

  14. The area of red planet where the Mars Rover Landed?  

    In Which Day world Telecom Day Celebrated?  

    Laser is used for what?

    a) Treatment of Cancer

    b) Treatment of Eyes

    c) Treatment of Heart

    d) Treatment of Kidney

  15. Which country is not a Member of SAARC

    a) Bangladesh

    b) Myanmar

    c) Maldives

    d) Nepal  

    The New Biotechnology Software intorduced by TCS is?

  16. The New Biotechnology Software intorduced by TCS is?  What is Wi Fi?

  17. Which is the fastest Cruise Missile?

DRDO Placement Paper : DRDO Aptitude - General 1

Model for ECE:
Direct Theory question:
1. A triangular-square wave generator uses 
         * A sine wave oscillator and a comparator 
         * An integrator and a comparator 
         * A diffrentiator and comparator 
         * A sine wave oscillator and a clipper
2. An amplifier has two identical cascaded stages. Each stage has a BW of 20KHz. The overall BW
    shall be 
         * 10KHz 
         * 12.9KHz 
         * 20KHz 
         * 28.3HHz
Direct numerical problem:

  1. 1. A parabolic dish antenna has a diameter of 1m. the maximum possible ideal gain of the antenna at a wavelength 3.14cm is 
              * 20 dB 
              * 30 dB 
              * 40 dB 
              * 50 dB
  2. 2. The frequency deviation produced in a VHF carrier by a signal of 100Hz is 50KHz. The frequency modulation is 
              100 radians
              250 radians
              500 radians
              750 radians
    Application based theoretical or numerical problem:
  1. Which one of the pulses has the same form in time domain as well as in frequency domain
  2. Good voice reproduction via PCM requires 128 quantisation levels. If the BW of voice channel is 4KHz then data rate is
                  256 Kbps
                  128 Kbps
                  56 Kbps
                  28 Kbps

  3. Match the following:
    1. List 1 List2                                                                                     
    A. Thyristor 1. Second break down
    B. MOSFET 2. Large on-state drop
    C. IGBT 3. Small on state drop
    D. BJT 4. Slow device

    (a) A-4, B-3, C-2, D-1 (b) A-1, B-2, C-3, D-4
    (c) A-4, B-2, C-3, D-1 (d) A-1, B-3, C-2, D-4

  4. List 1 List2

    A. Free and forced response 1. Discrete time systems
    B. Z transform 2. Dirichlet conditions
    C. Probability theory 3. Non-homogenous differential equation
    d. Fourier series 4. Random process


    (a) A-1, B-3, C-2, D-4 (b) A-3, B-1, C-2, D-4
    (c) A-1, B-3, C-4, D-2 (d) A-3, B-1, C-4, D-2

    Assertion and reasoning type:

    The following item consists of two statements labeled as Assertion A and the other as Reason R. Use the following codes:
    (a) Both A&R are individually true and R is the correct explanation of A
    (b) Both A & R are individually true and R is not the correct explanation of A
    (c) A is true and R is false
    (d) A is false and R is true

  5. AEvery materials has a different value of energy band gap except metals which have no band gap
    R The energy band gap is decided by the equilibrium lattice constant, which is different in different materials.
  6. AOp-amp are commonly used in instrumentation
    R Op-amps do not load the circuit due to their very high input impedance

    Problem based on circuits and graphs:

    Some examples:
    For circuits: HW rectifier, voltmeter, RC or RLC or RL transients, feedback systems, clipper, clamper, transistor biasing,555 circits, logic gates, counters, bridges and wattmeters.
    Graphs: Frequency response H(s),open loop gain from root loci, Nyquist plot, transfer functions etc


DRDO Placement Paper : DRDO Aptitude - General

This piece of info in obtained from the DRDO SET exam conducted in Sept 2003. Still the questions is not yet  complete.          

General Pattern

-There are 2 sections:A and B                                                                      
-,A, section consists of technical questions relevant to your field[100 questions]                    
-,B, section consists of a mix of Analytical,Quantitative and General Knowledge questions[50 questions]
4 marks for correct answers and -1 for wrong answers

Section ,A, questions

1) Banker,s algorithm is used for:Deadlock Avoidance
2) A LOT of questions were based on generating strings from a given grammar.                
3) A circle(dot) shown in the PCB is:Vcc/Grnd/Pin 1/Pin 14
4) Program Segment Prefix in MS-DOS 5.0 is:
5) Some IP addresses were given and the question was to select the private addess from it(?)
6) 10Base2 and 10Base5 wires refers to:
7) A question on sliding-window protocol
8) Which of the following require a driver?:disk/cache/ram/cpu
9) A LOT of mathematical questions which were asked from calculus,trigonometry...

Section ,B, questions

1) Coldest planet:Pluto
2) INS Shivali is the first:
3) Which one of the following was NOT indegineously developed?:Prithvi/Akash/Agni/...        
4) Full form of SARS
5) Anthrax is a :Virus/Bacteria/.../...
6) Dakshina Gangothri is:Ganga,s origin/Indian camp @ antartica/.../...
7) Which of the following is a chemical weapon:Mustard Gas/Marsh Gas/.../...
8) A question based on Coding and Decoding
9) Another question similar to above
10) Question on series completion
11) Another series completion question
12) Where is Institute of Forensic Science?:Hyderabad
13) A G.K question based on X and Y chromosomes in males and females 

By Category
Post Your Resume Here