Thermal Engineering 40

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Objective Questions and Answer: Thermal Engineering 40

Subject: Thermal Engineering 40

Part 40: Objective questions and answers of Thermal Engineering

 

Q1. Film boiling occurs at

a) Very low pressure

b) Atmospheric pressures

c) Medium pressures

d) Very high pressures

 

Q2. Fire tube boilers are limited to a maximum design working pressure of

a) 1 kg/cm

b) 6 kg/cm

c) 17 kg/cm^2

d) 100 kg/cm^2

 

Q3. For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has

a) More heating surface

b) Less heating surface

c) Equal heating surface

d) Heating surface depends on other parameters

 

Q4. In water wall furnace, the heat is transferred to the water-walls by

a) Convection

b) Radiation

c) Conduction

d) Radiation and conduction

 

Q5. Relative percentage of heat absorbed through the heat transfer of(i) furnace water wall,(ii) boiler bank,(Hi) superheater,(iv) economiser,(v) airheater of a typical boiler of 200

MW capacity would be of the order of

a) 48:20:15:7:10

b) 10:7:15:20:48

c) 20:48:7:15:10

d) 7:15:20:10:48

 

Q6. The feed check valve is used in order to

a) Regulate flow of boiler water

b) Check level of water in boiler drum

c) Recirculate unwanted feed water

d) Allow high pressure feed water to flow to drum and not allow reverse flow to take place

 

Q7. The size of a boiler drum in pulverized fuel fired boiler, as its size and capacity, (steam pressure and flow ratings

a) Increases

b) Decreases

c) Remains unchanged

d) Increases/decreases depending on steam temperature requirements

 

Q8. Feed water conditioning in thermal power plants in done to

a) Reduce hardness and for removal of solids

b) Increase efficiency of thermal power plant

c) Increase *heat transfer rate

d) Increase steam parameters

 

Q9. The basic job of feed water treatment in boilers is to overcome the problem of

a) Corrosion

b) Scale

c) Carry-over

d) All of the above.

 

Q10. Efficiency of a thermal cycle increases by

a) Regeneration

b) Reheating of steam

c) Both (a) and (b)

d) Cooling of steam

 

Q11. Which of the following cycles is not a reversible cycle?

a) Carnot

b) Ericsson

c) Stirling

d) None of the above.

 

Q12. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as

a) Dual combustion cycle

b) Diesel cycle

c) Atkinson cycle

d) Rankine cycle

 

Q13. The efficiency of Diesel cycle with decrease in cut off

a) Increases

b) Decreases

c) Remains unaffected

d) First increases and then decreases

 

Q14. Which of the following cycles has maximum efficiency?

a) Rankine

b) Stirling

c) Carnot

d) Brayton

 

Q15. The ideal efficiency of a Brayton cycle without regeneration with increase ni pressure

ratio will

a) Increase

b) Decrease

c) Remain unchanged

d) Increase/decrease depending on application

 

Q16. The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will

a) Increase

b) Decrease

c) Remain unchanged

d) Increase/decrease depending on ap-plication

 

Q17. The following cycle is used for air craft refrigeration

a) Brayton cycle

b) Reversed-Brayton cycle.

c) Carnot cycle

d) Bell-Coleman cycle

 

Q18. Gas turbine cycle consists of

a) Two isothermals and two isentropic

b) Two isentropic and two constant volumes

c) Two isentropic, one constant volume and one constant pressure

d) Two isentropic and two constant pressures

 

Q19. The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that

a) Carnot cycle can't work with saturated steam

b) Heat is supplied to water at temperature below the maximum temperature of the cycle

c) A rankine cycle receives heat at two places

d) Rankine cycle is hypothetical

 

Q20. Change in enthalpy of a system is the heat supplied at

a) Constant pressure

b) Constant temperature

c) Constant volume

d) Constant entropy

 

Part 40: Objective questions and answers of Thermal Engineering

Q1. Answer: a

Q2. Answer: c

Q3. Answer: a

Q4. Answer: b

Q5. Answer: a

Q6. Answer: d

Q7. Answer: b

Q8. Answer: a

Q9. Answer: d

Q10. Answer: c

Q11. Answer: d

Q12. Answer: c

Q13. Answer: a

Q14. Answer: c

Q15. Answer: a

Q16. Answer: b

Q17. Answer: b

Q18. Answer: d

Q19. Answer: b

Q20. Answer: a

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