250+ TOP MCQs on Combined Cycle Plants, Nuclear and Thermionic Power Generation and Answers

Power Plant Engineering Multiple Choice Questions on “Combined Cycle Plants, Nuclear and Thermionic Power Generation”.

1. The maximum steam temperature in a power cycle in degree centigrade is?
a) 600
b) 500
c) 300
d) 100
Answer: a
Clarification: The maximum steam temperature in a power cycle is 600 degree centigrade.

2. The temperature in a dry bottom pulverised coal furnace, in degree Celsius is about?
a) 1200
b) 1300
c) 1400
d) 2000
Answer: b
Clarification: The temperature in a dry bottom pulverised coal furnace, in degree Celsius is about 1300.

3. What happens to the availability in a combined cycle plant?
a) decreases
b) increases
c) remains same
d) cannot say
Answer: a
Clarification: There is a great thermal irreversibility & a decrease of availability because of heat transfer from combustion gases to steam through such a large temperature difference.

4. By superposing a high temperature power plant as a topping unit to the steam plant, the energy conversion efficiency achieved is?
a) higher
b) lower
c) maximum
d) minimum
Answer: a
Clarification: By superposing a high temperature power plant as a topping unit to the steam plant, the energy conversion efficiency achieved is higher from fuel to electricity.

5. Which of the following is not a type of Combined Plant?
a) Sodium- mercury-Potassium plant
b) Gas turbine-Steam turbine plant
c) Thermionic steam plant
d) Thermoelectric steam plant
Answer: a
Clarification: Sodium-mercury-potassium plants have two topping fluids which is impossible for a plant to possess.

6. Which of these is not a component of nuclear reactor?
a) reactor core
b) refractor
c) control rod
d) biological shield
Answer: b
Clarification: A reflector rather than a refractor is a component of nuclear reactor.

7. Which of these is not a merit of nuclear power?
a) amount of fuel required is small
b) plant requires a huge amount of area
c) demand for coal and oil is reduced
d) most economical in large quantities
Answer: b
Clarification: A small amount of area is required.

8. The thermionic generator is essentially which kind of device?
a) low voltage & high current
b) high voltage & high current
c) low voltage & low current
d) high voltage and high current
Answer: a
Clarification: Thermionic generator is essentially a low-voltage & high-current device.

9. What efficiencies of thermionic power generator have been realised?
a) 50-60%
b) 40-50%
c) 10-20%
d) 30-40%
Answer: c
Clarification: Efficiency of 30-40% has been realised in thermionic generators.

10. The maximum electron current per unit area provided by an emitter is given by (where J = current density, T = absolute temperature in K, ɸ = work function in keV, k = Boltzmann’s constant & A=emission constant)
a) J = AT exp(-ɸ/kT)
b) J = AT (-ɸ/kT)
c) J = AT2 exp(-ɸ/kT)
d) J = exp(-Aɸ/kT2)
Answer: c
Clarification: The maximum current density is given by Richardson-Dushman equation.

11. In an electron beam, the average kinetic energy of an electron is given by __________
a) 2KT
b) 3KT
c) 1.5KT
d) 2.5KT
Answer: a
Clarification: The average kinetic energy is equal to 2KT.

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