Thermodynamics 5

COEP
Lets Crack Online Exam

Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject:  Thermodynamics 5

Part 5: List for questions and answers of Thermodynamics

Q1. The boiler in which the tubes are surrounded by hot gases is called as
a) Fire tube boiler
b) Water tube boiler
c) Both a. And b
d) None of the above

Q2. Comparing fire tube and water tube boilers, which boiler can produce comparatively higher pressure steam than another for the same capacity?
a) Fire tube boiler
b) Water tube boiler
c) Both can produce steam at same pressure for the same capacity
d) None of the above

Q3. What is the purpose of using economizer in the boiler?
a) To heat feed water by utilizing heat from exhaust gases
b) To heat feed water by utilizing some heat from superheated steam
c) To superheat steam
d) None of the above

Q4. How is the natural draught produced for exhaust gases?
a) By using fan
b) By using chimney
c) By using gravity
d) None of the above

Q5. The purpose of superheated in a boiler is
a) To increase the temperature of saturated steam with increase in its pressure
b) To increase the temperature of saturated steam without increase in its pressure
c) To increase the temperature of feed water for better efficiency
d) None of the above

Q6. The natural draught in the steam generator depends upon
a) The air condition outside the chimney
b) The temperature of exhaust gases
c) Both a. And b
d) None of the above

Q7.Which device used to separate condensate from the steam without letting steam escape?
a) Condenser
b) Steam valve
c) Steam trap
d) None of the above

Q8. What is the disadvantage of natural draught?
a) It has less life
b) It has more maintenance cost of cleaning and more capital cost to build the chimney
c) The available draught decreases with increasing outside air temperature
d) All of the above

Q9. What is the ph value of water permissible for boiler?
a) 0
b) 7
c) Slightly less than 7
d) Slightly more than 7

Q10. The formation of scale boiler leads to
a) Decrease in efficiency of boiler
b) Increase in efficiency of boiler
c) Increase in heat transfer
d) Decrease in maintenance of boiler

Q11. The ideal refrigeration cycle is like
a) Carnot cycle
b) Reversed Carnot cycle
c) Rankine cycle
d) Reversed Rankine cycle

Q12. Where is main concentration in refrigeration for its calculation?
a) High temperature reservoir
b) Low temperature reservoir
c) Doth high temperature and low temperature reservoirs
d) None of the above

Q13. Which device is used for the expansion of refrigerant in vapour compression
refrigeration cycle?
a) Throttling valve
b) Capillary tube
c) Either throttling valve or capillary tube
d) None of the above

Q14. Wet compression is ______
a) More dangerous than the dry compression in vapour compression refrigeration
system
b) Less dangerous than the dry compression in vapour compression refrigeration
system
c) Equally preferable in vapour compression refrigeration system
d) Cannot say

Q15. The heat required to melt 1 tonne of ice in 12 hours is equivalent to
a) One tonne of refrigeration
b) Two tonne of refrigeration
c) Half tonne of refrigeration
d) Four tonne of refrigeration

Q16. What is the main reason behind subcooling of liquid refrigerant at the condenser outlet in vapour compression refrigeration system?
a) To increase the refrigerating effect
b) To reduce the mass of vapour formed during expansion process
c) To reduce vapour bubbles which obstruct the flow of liquid refrigerant
d) All of the above

Q17. What is the result of superheating of vapour at the evaporator outlet?
a) No liquid droplets will travel to the compressor
b) The compressor discharge temperature increases
c) Both a. And b
d) None of the above

Q18. Which expansion device is capable of regulating the flow of refrigerant according to the load on the evaporator?
a) Capillary tube
b) Throttle valve
c) Both a. And b
d) None of the above

Q19. Which compressor is used, when volume flow rate of refrigerant is very large?
a) Rotary compressor
b) Reciprocating compressor
c) Centrifugal compressor
d) None of the above

Q20. Higher efficiency in the combustion of solid fuel cannot be achieved by
a) Proper fuel preparation
b) Keeping the flue gas exhaust temperature very high
c) Adopting efficient-fuel firing technique & equipment
d) Supplying correct quantity of combustion air

Part 5: List for questions and answers of Thermodynamics

Q1. Answer: b

Q2. Answer: c

Q3. Answer: a

Q4. Answer: b

Q5. Answer: b

Q6. Answer: c

Q7. Answer: c

Q8. Answer: c

Q9. Answer: d

Q10. Answer: a

Q11. Answer: b

Q12. Answer: b

Q13. Answer: c

Q14. Answer: a

Q15. Answer: b

Q16. Answer: d

Q17. Answer: c

Q18. Answer: b

Q19. Answer: c

Q20. Answer: b