Thermal Engineering 9

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Objective Questions and Answer: Thermal Engineering 9

Subject: Thermal Engineering 9

Part 9: Objective questions and answers of Thermal Engineering

 

Q1. Which of the following processes is irreversible process?

a) Isothermal

b) Adiabatic

c) Throttling

d) All of the above

 

Q2. In order that a cycle be reversible, following must be satisfied

a) Free expansion or friction resisted expansion/compression process should not be encountered

b) When heat is being absorbed, temperature of hot source and working sub¬stance should be same

c) When beat is being rejected, temperature of cold source and working sub-stance should be same

d) All of the above

 

Q3. For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be

a) Zero

b) Minimum

c) Maximum

d) Infinity

 

Q4. Minimum work in compressor is possible when the value of adiabatic index n is equal to

a) 0.75

b) 1

c) 1.27

d) 1.35

 

Q5. Molecular volume of any perfect gas at 600 x 103 N/m2 and 27°C will be

a) 4.17m3/kgmol

b) 400 m3/kg mol

c) 0.15 m3/kg mol

d) 41.7 m3/kg mol

 

Q6. A gas is compressed in a cylinder by a movable piston to a volume one-half its original volume. During the process 300 kj heat left the gas and internal energy remained same. The work done on gas in Nm will be

a) 300 Nm

b) 300,000 Nm

c) 30 Nm

d) 3000 Nm

 

Q7. The more effective way of increasing efficiency of Carnot engine is to

a) Increase higher temperature

b) Decrease higher temperature

c) Increase lower temperature

d) Decrease lower temperature

 

Q8. Entropy change depends on

a) Heat transfer

b) Mass transfer

c) Change of temperature

d) Thermodynamic state

 

Q9. For reversible adiabatic process, change in entropy is

a) Maximum

b) Minimum

c) Zero

d) Unpredictable

 

Q10. Isochoric process is one in which

a) Free expansion takes place

b) Very little mechanical work is done by the system

c) No mechanical work is done by the system

d) All parameters remain constant

 

Q11. According to first law of thermodynamics

a) Work done by a system is equal to heat transferred by the system

b) Total internal energy of a system during a process remains constant

c) Internal energy, enthalpy and entropy during a process remain constant

d) Total energy of a system remains constant

 

Q12. Energy can neither be created nor destroyed but can be converted from one form to other is inferred from

a) Zeroth low of thermodynamic

b) First law of thermodynamics

c) Second law to thermodynamics

d) Basic law of thermodynamics

 

Q13. First law of thermodynamics furnishes the relationship between

a) Heat and work

b) Heat, work and properties of the system

c) Various properties of the system

d) Various thermodynamic processes

 

Q14. Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant

a) Pressure

b) Temperature

c) Volume

d) Internal energy

 

Q15. In an isothermal process, the internal energy

a) Increases

b) Decreases

c) Remains constant

d) First increases and then decreases

 

Q16. Change in internal energy in a closed system is equal to heat transferred if the reversible process takes place at constant

a) Pressure

b) Temperature

c) Volume

d) Internal energy

 

Q17. According to first law of thermodynamics

a) Mass and energy are mutually convertible

b) Carnot engine is most efficient

c) Heat and work are mutually convertible

d) Mass and light are mutually convertible

 

Q18. Total heat of a substance is also known as

a) Internal energy

b) Entropy

c) Thermal capacity

d) Enthalpy

 

Q19. First law of thermodynamics

a) Enables to determine change in internal energy of the system

b) Does not help to predict whether the system will or not undergo a change

c) Does not enable to determine change in entropy

d) All of the above.

 

Q20. Addition of heat at constant pressure to a gas results in

a) Raising its temperature

b) Raising its pressure

c) Raising its volume

d) Raising its temperature and doing external work

 

Part 9: Objective questions and answers of Thermal Engineering

 

Q1. Answer: c

Q2. Answer: d

Q3. Answer: a

Q4. Answer: b

Q5. Answer: a

Q6. Answer: b

Q7. Answer: d

Q8. Answer: a

Q9. Answer: c

Q10. Answer: c

Q11. Answer: d

Q12. Answer: b

Q13. Answer: b

Q14. Answer: a

Q15. Answer: c

Q16. Answer: c

Q17. Answer: c

Q18. Answer: b

Q19. Answer: d

Q20. Answer: d

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