Thermal Engineering 30

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Objective Questions and Answer: Thermal Engineering 30

Subject: Thermal Engineering 30

Part 30: Objective questions and answers of Thermal Engineering

 

Q1. Turbofan engine employs

a) One air stream

b) Two or more air streams

c) No air stream

d) Solid fuel firing

 

Q2. Pressure ratio in gas turbines is the ratio of

a) Compressor pressure ratio

b) Highest pressure to exhaust pressure

c) Inlet pressure to exhaust pressure

d) Pressures across the turbine

 

Q3. Pick up the false statement

a) Gas turbine is a self-starting unit

b) Gas turbine does not require huge quantity of water like steam plant

c) Exhaust losses in gas turbine are high due to large mass flow rate

d) Overall efficiency of gas turbine plant is lower than that of a reciprocating engine

 

Q4. The efficiency and work ratio of a gas turbine plant can be increased by

a) Using multi-stage compressor with cooler

b) Adding heat exchanger

c) Injecting water in/around combustion chamber

d) All of the above.

 

Q5. Pick up the correct statement

a) Closed cycle gas turbine is an I.C engine

b) Gas turbine uses same working fluid over and over again

c) Air-fuel ratio in a gas turbine is 100 : 1

d) Thrust in turbo-jet is produced by nozzle exit gases.

 

Q6. The compression ratio in a jet engine varies proportional to

a) H speed

b) Speed

c) Altitude

d) V speed

 

Q7. The efficiency of jet engine is

a) Higher at ground

b) Higher at high altitudes

c) Same at all altitudes

d) Higher at high speed

 

Q8. The indicated work per unit mass of air delivered is

a) Directly proportional to clearance volume

b) Greatly affected by clearance volume

c) Not affected by clearance volume

d) Inversely proportional to clearance volume

 

Q9. It is not possible to use closed gas turbine cycle in aeronautical engines because

a) It is inefficient

b) It is bulky

c) It requires cooling water for its operation

d) None of These

 

Q10. Intercooling in gas turbine results in

a) Increase in net output but decrease in thermal efficiency

b) Increase in thermal efficiency but decrease in net output

c) Increase in both thermal efficiency and net output

d) Decrease in both thermal efficiency and net output

 

Q11. For water, at pressures below atmospheric,

a) Melting point rises slightly and boiling point drops markedly

b) Melting point rises markedly and boiling point drops markedly

c) Melting point drops slightly and boiling point drops markedly

d) Melting point drops slightly and boiling point drops slightly

 

Q12. At very low temperature, the melting and boiling temperatures become equal. This temperature is

a) 373°K

b) 273.16°K

c) 303°K

d) 0°K.

 

Q13. The critical pressure at which latent heat of vaporization is zero is

a) 225.65 kgf/cm^2

b) 273 kgf/cm^2

c) 100 kgf/cm^2

d) 1 kgf/cm^2

 

Q14. The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is

a) Less

b) More

c) Equal

d) May be less or more depending on temperature

 

Q15. The saturation temperature of steam with increase in pressure increases

a) Linearly

b) Rapidly first and then slowly

c) Slowly first and then rapidly

d) Inversely

 

Q16. Carbonization of coal is the process of

a) Pulverizing coal in inert atmosphere

b) Heating wood in a limited supply of air at temperatures below 300°C

c) Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel

d) Binding the pulverized coal into briquettes

 

Q17. Coke is produced by

a) Pulverizing coal in inert atmosphere

b) Heating wood in a limited supply of air at temperatures below 300GC

c) Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel

d) Binding the pulverized coal into brackets

 

Q18. Heating of dry steam above saturation temperature is known as

a) Enthalpy

b) Superheating

c) Super saturation

d) Latent heat

 

Q19. Superheating of steam is done at

a) Constant volume

b) Constant temperature

c) Constant pressure

d) Constant entropy

 

Q20. 1 kg is equal to

a) 9.81 Joules

b) All Joules

c) 427 Joules

d) 102 Joules

 

Part 30: Objective questions and answers of Thermal Engineering

 

Q1. Answer: b

Q2. Answer: b

Q3. Answer: a

Q4. Answer: d

Q5. Answer: d

Q6. Answer: b

Q7. Answer: b

Q8. Answer: c

Q9. Answer: c

Q10. Answer: a

Q11. Answer: a

Q12. Answer: b

Q13. Answer: a

Q14. Answer: a

Q15. Answer: b

Q16. Answer: c

Q17. Answer: c

Q18. Answer: b

Q19. Answer: c

Q20. Answer: a

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