Solved Question Paper of Recruitment Test (Computer Based Recruitment Test) conducted by UPSC for the Post of Deputy Controller of Explosives in Petroleum and Explosives Safety Organisation (PESO) held on 29.07.2018.

 


11. In a two component mixture at rest, the mass or molal flux of a component per unit area is proportional to the concentration gradient and is represented by: 

 and it is called as:
(a) Fourier law of heat flux
(b) Newton’s law of viscosity
(c) Reynolds Colbwin law
(d) Fick’s law

Answer: (d)

12.

Answer: (d)

13. Graetz number (G) described for the heat flow to the fluid flowing through a circular pipe is:

Answer: (a)

14. Consider the following statements:
1. Thermal conductivity decreases with increase in temperature
2. Thermal conductivity of pure metals increases with the increase in their impurity
3. Thermal conductivity of solid materials is weakly dependent on pressure
4. The ratio of the thermal and electrical conductivity for all metals is the same at the same temperature and directly proportional to absolute temperature

Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 3 and 4 only
(c) 1, 2 and 4 only
(d) 2, 3 and 4 only

Answer: (b)

15. Two fluids A and B exchange heat in a counter current heat exchanger. Fluid A enters at 420°𝐶 and has a mass flow rate of 1 kg/s. Fluid B enters at 20°𝐶 and has a mass flow rate of 1 kg/s. Effectiveness of the heat exchanger is 75%. If the specific heat of fluid A is 1 kJ/kg K and that of fluid B is 4 kJ/kg K, then the heat transfer rate (Q) is:
(a) 350 kJ
(b) 330 kJ
(c) 315 kJ
(d) 300 kJ

Answer: (d)

16. Two parallel rectangular surfaces 1 cm ×2 cm are opposite to each other at a distance of 4 m. The surfaces are black and at 100°𝐶 and 200°𝐶 . The heat exchange between the two surfaces by radiation is:
(a) 149.5 𝑊
(b) 137.5 𝑊
(c) 125.5 𝑊
(d) 113.5 𝑊

Answer: (a)

17. Mass transfer does not take place by:
(a) Dissolution
(b) Diffusion
(c) Convection
(d) Change of phase

Answer: (a)

18. For the turbulent flow, the Reynolds number (Re) is:
(a) >1000 but <2000
(b) Between 2000 to 4000
(c) <2000
(d) >4000

Answer: (d)

19. 

Answer: (c)

20. 
(a) 25 𝑚/𝑠
(b) 20 𝑚/𝑠
(c) 15 𝑚/𝑠
(d) 10 𝑚/𝑠

Answer: (b)