Power Plant Engineering Questions and Answers Part-15

1. The lower is the value of heat rate __________ is the efficiency.
a) lower
b) higher
c) same
d) depends on further parameters

Answer: b
Explanation: The parameter that readily reflects the fuel economy is the heat rate, which is inversely proportional to the efficiency.

2. Overall efficiency is the ratio of power available at generator terminals to rate of energy released by combustion of fuel.
a) true
b) false
c) can’t say
d) not true for all conditions

Answer: a
Explanation: Efficiency is power generated / power supplied.

3. The steam from steam generator of a nuclear power plant is best described as __________
a) superheated steam
b) supercritical steam
c) saturated dry steam
d) saturated wet steam

Answer: d
Explanation: Steam contains moisture after coming out of boiler.

4. Under certain conditions, the specific enthalpies of dry steam, saturated water and wet steam are 2783 kJ/kg, 1219 kJ/kg and 2750 kJ/kg respectively. Determine the dryness fraction of wet steam.
a) 0.01
b) 0.02
c) 0.021
d) 0.03

Answer: c
Explanation: Specific enthalpies of saturated water (hl) and dry steam (hs) are 1219 kJ/kg and 2783 kJ/kg. Substituting these values in the equation “hws= xdhg+(1-xd)hl” gives the dryness fraction as 0.021.

5. What includes fixed cost?
a) cost of land, Cost of building, Cost of equipment, Cost of installation
b) interest
c) management cost
d) all of the mentioned

Answer: d
Explanation: These are the parameters that cannot be neglected and come under the fixed cost.

6. Name the major isotope present in steam generated in a Boiling Water Reactor.
a) N-16
b) D-32
c) N-32
d) D-16

Answer: a
Explanation: It is more economical and more efficient.

7. Efficiency of a power plant is more in summers or winters?
a) summers
b) winters
c) same in both
d) depends on variation

Answer: b
Explanation: In summers the heat loss is more so efficiency is less.

8. What is the mechanical efficiency of turbine?
a) brake output / internal output
b) internal output / brake output
c) blade energy / energy supplied
d) none of the mentioned

Answer: b
Explanation: internal output / brake output

9. The steam power plant is a bulk energy converter where fuel energy is converted to?
a) heat energy
b) electrical energy
c) chemical energy
d) none of the mentioned

Answer: b
Explanation: Energy conversion in a steam power plant is as below
Fuel energy to Electricity.

10. Rate of energy released by the combustion of the fuel is given by?
a) Fuel burning rate x Calorific Value of the fuel
b) Fuel burning rate / Calorific Value of the fuel
c) Fuel burning rate + Calorific Value of the fuel
d) Fuel burning rate – Calorific Value of the fuel

Answer: a
Explanation: Rate of energy released by the combustion of the fuel is given by,
Fuel burning rate x Calorific Value of the fuel.