Power Plant Engineering Objective Questions And Answers

1. Seeding material commonly used in MHD generator is

(a) sodium.
(b) aluminum.
(c) potassium.
(d) cesium.

2. Which of the following liquid metal is not used as an MHD working fluid ?

(a) Potassium.
(b) Sodium
(c) Lithium
(d) all of the above

3. The exhaust from an MHD generator is at a temperature of about

(a) 800°C
(b) 2,200°C
(c) 3,500°C
(d) 1,200°C

4. In an MHD generator the ionization potential of the seeding material should be

(a) very high.
(b) the lowest possible.
(c) neither high or low.
(d) either high or low.

5. An MHD system for efficient operation needs

(a) a magnet capable of producing high magnetic flux density.
(b) injection and recovery of seed material
(c) arrangement for superheating of air.
(d) all of the above.

6. The advantage(s) of an MHD system is/are

(a) low pollution.
(b) good efficiency.
(c) conservation of fuel.
(d) absence of moving parts.
(e) all of the above.

7. The concept of MHD generation depends much more on the……..of the gas in the duct.

(a) permeability
(b) permittivity
(c) conductivity
(d) none of these

8. The materials used for electrodes in thermoelectric generators are

(a) metal conductors.
(b) carbon.
(c) semiconductors.
(d) insulators.

9. Thermionic convertor utilizes

(a) Seebeck effect.
(b) thermionic emission effect.
(c) Peltier effect.
(d) Thomson effect.

10. The solar or photovoltaic cell converts

(a) chemical energy into electrical energy.
(b) solar radiations into electrical energy.
(c) solar radiations into thermal energy.
(d) thermal energy into electrical energy.

11. Photovoltaic solar energy conversion system makes use of

(a) solar pond.
(b) fuel cell.
(c) Edison cell.
(d) none of the above.

12. The efficiency of solar cell is about

(a) 25%
(b) 15%
(c) 40%
(d) 60%

13. Solar cells are made of

(a) aluminum.
(b) germanium.
(c) silicon.
(d) cadmium.

14. The voltage of a solar cell is

(a) 0.5 – 1 V
(b) 1 – 2 V
(c) 2 – 3 V
(d) 4 – 5 V

15. The output of a solar cell is of the order of

(a) 0.5 W
(b) 1.0 W
(c) 5.0 W
(d) 10.0 W

16. Solar cells, for power generation, have the mains drawback(s) of

(a) low efficiency.
(b) lack of availability.
(c) high cost and maintenance problems.
(d) all of the above.

17. A module is a

(a) series-arrangement of solar cells.
(b) parallel arrangement of solar cells.
(c) series parallel arrangement of solar cells.
(d) none of the above.

18. For satellites the source of energy is

(a) solar cell.
(b) fuel cell.
(c) Edison cell.
(d) cryogenic storage.

19. Fuel cells have conversion efficiencies of about

(a) 25%
(b) 40%
(c) 65%
(d) 85%

20. Fuel cell converts chemical energy into

(a) heat energy.
(b) low-voltage direct current electrical energy.
(c) low-voltage alternating current electrical energy.
(d) mechanical energy.