# DRDO Previous question papers| DRDO Model Question Paper 2012

By | August 4, 2012

DRDO Ceptam-05 Entry test will be held on 5th August 2012. Questions from DRDO Previous papers are given below. Readers can post answers keys to the following DRDO questions in the comment box, which will be helpful to the others.

Questions from DRDO Previous papers (Memory based)

1. To prepare a solution of 50% sulfuric acid, a dilute waste acid containing 27% sulfuric acid is fortified with a fresh acid containing 96% sulfuric acid. The amount of fresh acid required for each 100 kg of dilute waste acid is

(A)       13.5 kg            (B)       25 kg   (C)       50 kg   (D)       100 kg

2. A flue gas analysis gave 10% O2, 25% CO2 and 65% N2 at 160 °C and 760 mm Hg. The ratio of partial pressures of CO2 to O2 is equal to

(A) 1 (B) 2               (C)  2.5            (D)  4

3. In the extraction of nicotine from a nicotine-water solution by kerosene, the pressure and temperature are kept constant. The available degree(s) of freedom is/are

(A) 0            (B) 1               (C) 2                (D)  3

4. A gas is being compressed from an enthalpy of 489 kJ/kg to 509 kJ/kg in a steady state open process. The entry and exit velocities of the gas are zero and 60 m/s, respectively. Assume that there is no heat loss or gain, no reaction, and potential energy change is negligible. If the load is 100 kg/h of gas, the work done on the gas is equal to

(A)  2000 kJ    (B)  2180 kJ     (C)  2500 kJ    (D)  3000 kJ

5. The vapor pressures of benzene and toluene at 70°C are 4 and 6 atm, respectively. A liquid feed of 0.6 moles of toluene at the same temperature is vaporized. Assuming Raoult’s law, the vapor phase mole fraction of benzene at equilibrium is approximately.

(A) 0.30           (B) 0.40           (C) 0.50           (D) 0.60

6. An oil film of viscosity u and thickness h is sheared between a solid stationary wall and a circular disc of radius R, where h < < R. The circular disc is rotating with angular speed w.   For the same thickness of the film, if the radius of the disc is doubled, the angular speed remaining the same, by what factor the torque on the disc increases?

(A) 2                (B) 4                (C) 8                (D) 16

7. A reciprocating pump has a piston of cross-sectional area A and is connected to a crank of radius r which is rotating with angular velocity ω. The pump is connected to the suction and the delivery pipes whose internal cross-sectional area is A1. The maximum velocity of the fluid element in the suction or delivery pipe is

A system is taken from state A to state B along path ACB where 100 J of heat flows into the system and the system does 40 J of work.

8. How much heat flows into the system along path AEB if the work done by the system is 20 J?

(A)  20 J          (B)  40 J           (C)  60 J          (D)  80 J

9. The system returns from B to A along path BDA. If the work done on the system is 30 J, what will be the amount of heat liberated/generated?

(A) -90 J          (B)  90 J           (C)  30 J          (D)  -30 J

10. Acentric factor for Argon is

(A)  >1             (B)  1               (C)   0              (D)  < 1

11. Wet steam at 270 °C enters a throttling calorimeter with enthalpies of 1200 kJ/kg and 2800 kJ/kg in liquid and gas phase, respectively. It leaves as supersaturated steam at 0.1 MPa and 120 °C with an enthalpy of 2700 kJ/kg. The quality of steam is

(A) 14/16         (B) 13/16         (C) 15/16         (D) 27/40

A reversible heat engine absorbs 800 kJ as heat from a reservoir at 600 K and rejects 100 kJ energy as heat to a reservoir at 300 K, as shown in the following figure.

12. The heat interaction (Q) with reservoir at 400 K is

(A)  – 600 kJ    (B)  400 kJ       (C)  – 400 kJ    (D)  600 kJ

13. The work done (W) by the engine is

(A)  500 kJ      (B)  400 kJ       (C)  350 kJ      (D)  300 Kj

14. The decrease in the Helmholtz Free Energy for system in a given process for which initial and final temperatures are equal to the surrounding temperature indicates.

(A) Maximum work obtained from the system

(B) Minimum work obtained from the system

(C) Minimum work which can be done on the system

(D) Both (A) and (C)

15. In a dry crushing operation the mean diameter of the feed and product particles are 100 mm and 1 mm, respectively. The sphericity of the feed and product particles are 0.5 and 1.0, respectively. If the feed particles of 200 mm diameter with the same sphericity are handled at the same feed rate, what will be the percentage increase in power requirement assuming that the product remains the same?

16. Which of the following is INCORRECT about the boundary layer development over flat infinite plate?

(A) The fluid velocity at solid-liquid interface is zero

(B) The shear rate inside the boundary layer is not zero

(C) The boundary layer thickness increases with distance from the leading edge

(D) The flow in the boundary layer close to the leading edge is turbulent

17. Choose the INCORRECT statement from the following:

(A)       SBR compared to natural rubber has poor tensile strength

(B)       Silicone is an inorganic polymer

(C)       Nylon-6 is a polyamide

(D)       Neoprene is an elastomer

18. Cetane number of diesel is the measure of its

(A)       smoke point                  (B)       ignition delay

(C)       viscosity                       (D)       oxidation stability

19. Match the following:

(1)        Permanent hardness of water                (P) Steam distillation

(2)        Alkyl group of detergent                      (Q)Cation/anion exchanger

(3)        Rancidity of oil                                   (R) Hydrogenation

(4)        Essential oil                                        (S) Hydrophobic

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

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

20. Match the following:

(2)        Margarine                     (Q)       Pesticide

(3)        Litharge                        (R)       Enzyme

(4)        Lipase                          (S)       Fat

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

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

21. Choose the CORRECT statement from the following:

(A)       Aromatics have lowest octane number

(B)       Paraffins are the hardest to crack

(C)       Dearomatisation of kerosene increases its smoke point

(D)       Aniline point is a property of LPG

22. `Total capital investment’ for a chemical process plant comprises of the fixed capital investment and the

(A)       working capital             (B)       indirect production costs

(C)       direct production costs  (D)       overhead costs

23. Which of the following results in book values greater than those obtained with the straight line method?

(A)       Declining balance method                      (B)       Sum-of-the years digit method

(C)       Multiple straight line method                  (D)       Sinking fund method

24. Which of the following is NOT a function of baffle in the shell-and-tube heat exchanger?

(A)       Direct the flow across the tube bundle

(B}      Support the tube from sagging

(C)       Arrest the vibration of the tubes

(D)       Decrease the turbulence of the fluid

25. Solenoid valve works like

(A)       Proportional controller              (B)       PD controller

(C)       PID controller                           (D)       On-off controller

26. A control system is unstable if the open loop frequency response exhibits an amplitude ratio exceeding unity at the cross-over frequency. This is

(A)       Bode stability criteria    (B)       Routh stability criteria

(C)       Nyquist criteria             (D)       Root-locus criteria

27. The symbol of the type __________  denotes

(A)       Pneumatic line               (B)       Fluid pressure line

(C)       Electrical line                (D)       Software link

28. Ordinary mercury-in-glass thermometer (without any covering or air gap) is an

example of

(A) zero-order system                     (B)       first-order system

(C)     second-order system                (D)       third-order system

Chemical A reacts to form R (k1 = 8 hr-1) and chemical R reacts to form S (k2 = 3 hr-1). In addition R slowly decomposes to form T (k3 = 1 hr-1). A solution containing 1 mol/litre of A is introduced into a batch reactor.

29. What is the maximum concentration of R (mol/lit)?

(A)  0.5            (B)  0.25          (C)   0.75         (D) 1.0

30. How long will it take (in hours) for R to reach its maximum concentration?

(A)  ln 2           (B) ln 2         (C)  ln 2       (D)       2 1n 2

Aqueous phase decomposition of A is investigated in two mixed flow reactors in series. The second reactor is having twice the volume of the first reactor. At steady state with a feed of 1 mole/litre and mean residence time of 96 seconds in first reactor, the concentration of A in the first reactor is 0.5 mol/litre and in the second 0.25 mol/litre.

31. The order of the reaction is

(A) 1                (B) 2                (C)  0               (D) 3

32. The rate constant (lit/mol-min) is

(A) 1.5             (B) 3                (C)  2               (D) 1.25

33. In an endothermic reaction, for an increase in temperature, the equilibrium conversion

(A)  rises                                              (B)  falls

(C)  remains constant                            (D)  first increases then decreases

34. The response curve for a step input signal from a reactor is called C curve. The variance of C curve in a `tank in series model’ comprising of `n’ tanks is

(A) n (B) 1/n (C) n0.5 (D) n2

35. Calculate the weight of the catalyst required for the 75% conversion of sample A (C AO = 8 mol/m3) in a mixed flow reactor at a flow rate of 1000 mole/min. (The weight time of the operation is 4.15 kg s/m3)

(A)  500 kg      (B)  519 kg      (C)  525 kg      (D)  600 kg

A waste stream of organic vapor in a gas from a process was adsorbed by solid particles in packed bed of length 20 cm. The breakpoint concentration is set at C/C0= 0.10 and the breakpoint time is 4 hours.

36. What will be the time equivalent to the unusable capacity of the bed up to the breakpoint time?

(A)  3 hours      (B)  1.5 hours               (C)  4 hours      (D)  3.6 hours

37. The stoichiometric capacity of the bed is 7.2 hours. What will be the length of unused bed for this operation?

(A)  7.2 cm      (B)  20 cm                    (C)  10 cm       (D)  4 cm

38. In liquid-liquid extraction, the solvent B is used to separate solute C from a given solution of A and C. If A and B are completely insoluble in one another, the selectivity of B will be

(A)       8         (B)       0          (C)       < 0       (D)       1

39. A saturated liquid mixture with 50% (mole basis) of more volatile component is to be separated in a continuous distillation column. The mole% of more volatile component in the distillate is 90. The constant relative volatility of more volatile component is 1.5. Assuming McCabe-Thiele method, the minimum reflux ratio for this operation is

(A) 3                (B) 2                (C) 2.5             (D) 1

40. In a perfectly mixed flow model, the ratio of the Murphree plate efficiency to the point efficiency is equal to

(A)  0               (B)  1               (C)  < 1            (D)  > 1

41. The eddy momentum diffusivity, the thermal diffusivity and the mass diffusivity will be same for most of the gases when

(A)       both Prandtl and Schmidt numbers are equal to 1.2

(B)       both Prandtl and Schmidt numbers are equal to 10.0

(C)       both Prandtl and Schmidt numbers are equal to 0.1

(D)       both Prandtl and Schmidt numbers are equal to 1.0

42. When some liquid nitrogen spills on the floor of a laboratory, the droplets move so briskly that they appear to be dancing before they disappear. This phenomenon

(A)       is related to pool boiling                        (B)       is related to film boiling

(C)       is related to nucleate boiling                   (D)       has nothing to do with boiling

43. When momentum diffusivity is greater than the thermal diffusivity, the velocity boundary layer

(A) develops faster than the thermal boundary layer

(B) develops slower than the thermal boundary layer

(C) grows  together

(D) disappears

44. Biot number (hL/k) is important for which mode of heat transfer?

(A)       Natural convection                    (B)       Forced convection

(C)       Transient heat conduction          (D)       Radiation

45. A U-tube manometer measures

(A)      absolute pressure at a point

(B)      local atmospheric pressure at a point

(C)      difference in total energy between two points

(D)      difference in pressure between two points

46. Two viscous liquids are to be blended by passing through a pipe. Which of the   following would be the most suitable condition for axial mixing?

(A)       Creeping flow                           (B)       Low Reynolds number flow

(C)       High Reynolds number flow      (D)       Plug flow

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