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Thursday, 4 August 2016

Generation of Electrical Energy - Multiple Choice Questions

Generation of Electrical Energy - Multiple Choice Questions Points : Generation of Electrical Energy multiple choice questions and answers, electrical objective type question answers, mcqs 1. An alternator converts
(i) sound energy into electrical energy
(ii) mechanical energy into electrical energy
(iii) electrical energy into mechanical energy
(iv) none of above

2. The most clean power plant is
(i) steam power plant
(ii) diesel power plant
(iii) hydro-electric plant
(iv) nuclear power plant

3. Diesel power plants are used as …………. plants.
(i) base load
(ii) peak load
(iii) standby
(iv) none of above

4. The basic unit of energy is
(i) watt
(ii) joule
(iii) watt/sec
(iv) joule/sec

5. The major heat loss in a steam power station occurs in
(i) boiler
(ii) condenser
(iii) superheater
(iv) none of above

6. The overall efficiency of a steam power station is
Overall efficiency = Thermal efficiency x …………..
(i) mechanical efficiency
(ii) electrical efficiency
(iii) prime mover efficiency
(iv) none of above

7. The thermal efficiency and electrical efficiency of a steam power station are 30% and 92% respectively. The overall efficiency of the station is
(i) 55.8%
(ii) 27.6%
(iii) 62.8%
(iv) 45%

8. The cheapest plant in operation and maintenance is
(i) steam power plant
(ii) nuclear power plant
(iii) hydroelectric plant
(iv) diesel power plant

9. The primary source of energy is
(i) sun
(ii) coal
(iii) water
(iv) none of above

10. 1 kWh = ……… kcal
(i) 610
(ii) 746
(iii) 520
(iv) 860

11. Nuclear reactors utilise the process of
(i) fusion
(ii) fission
(iii) both fusion and fission
(iv) none of above

12. The thermal efficiency of a steam power
station is about
(i) 28%
(ii) 69%
(iii) 80%
(iv) 75%

13. A thermal power station has a boiler efficiency of 85% and turbine efficiency of 90%. The thermal efficiency of the station is
(i) 52.5%
(ii) 29%
(iii) 76.5%
(iv) none of above

14. Mechanical energy is supplied to a d.c. generator at the rate of 4200 JJs. The generator delivers 32.2 A at 120 V. The efficiency of the generator is
(i) 62%
(ii) 75%
(iii) 81%
(iv) 92%

15. A generating station has a connected load of 43 MW and a maximum demand of 20 MW; the units generated being 61.5 x 106 kWh per annum. The demand factor is
(i) 0.823
(ii) 0.756
(iii) 0.465
(iv) 0.356

16. The cost of fuel transportation is minimum in ………. plant.
(i) nuclear power
(ii) steam power
(iii) diesel power
(iv) hydroelectric

17. The highest point on the daily load curve represents
(i) average demand
(ii) maximum demand
(iii) load factor
(iv) none of above

18. The load factor is generally
(i) more than 1
(ii) less than 1
(iii) equal to 1
(iv) none of above

19. The diversity factor is always
(i) equal to 1
(ii) less than 1
(iii) greater than 1
(iv) none of above

20. A power supply has domestic load having a maximum demand of 1500 kW. If the diversity factor and demand factor are 1.2 and 0.8 respectively, then connected domestic load is
(i) 1800kW
(ii) 2500kW
(iii) 2250kW
(iv) 1750kW

21. If the load factor of a power station increases, the cost per unit generated will
(i) increase
(ii) decrease
(iii) remain same
(iv) data incomplete

22. If the diversity factor increases, the maximum demand on power station
(i) remains same
(ii) increases
(iii) decreases
(iv) none of above

23. The overall efficiency of a steam power station is ………... its thermal efficiency.
(i) less than
(ii) more than
(iii) equal to
(iv) none of above

24. The load factor is generally
(i) more than 1
(ii) less than 1
(iii) greater than 1
(iv) none of above

25. In a power station,
(i) Reserve capacity = Plant capacity — Max. demand
(ii) Reserve capacity = Plant capacity — Average demand
(iii) Reserve capacity = Plant capacity — Max demand
(iv) Reserve capacity = Plant capacity + Average demand

26. A steam power station has an overall efficiency of 20% and 0.6 kg of coal is burnt per kWh of electrical energy generated. The calorific value of fuel is
(i) 7166kcal/kg
(ii) 5152 kcal/kg
(iii) 2458 kcal/kg
(iv) none of above

27. The base load power station supplies load …….. in a day.
(i) 10 hours
(ii) 16 hours
(iii) 24 hours
(iv) 12 hours

28. A generating station as an average demand of 15 MW. If the plant capacity factor is 50%, what is the plant capacity?
(i) 20MW
(ii) 10MW
(iii) 25 MW
(iv) 30 MW

29. In a thermal power station, economisers are used to heat
(i) air
(ii) steam
(iii) feed water
(iv) none of above

30. There are no standby losses in ............. plant.
(i) steam power
(ii) hydroelectric
(iii) nuclear power
(v) diesel power

31. The capacity of the power plant is generally made …..... more than the maximum demand to meet the future load requirements.
(i) 60% to 70%
(iii) 90% to 95%
(ii) 15% to 20%
(iv) 55% to 60%

32. The ideal load factor should be
(i) 1
(ii) 0.5
(iii) 0.2
(iv) 0.8

33. A power station has a maximum demand of 15000 kW. The annual load factor is 50% and plant capacity factor is 4O%. What is the plant capacity?
(i) 30000kW
(ii) 17500kW
(iii) 18750kW
(iv) 15250kW

34. In a thermal power station, superheater heats
(i) steam
(ii) air
(iii) feed water
(iv) none of above

35. In an interconnected grid system, the diversity factor of the whole system
(i) increases
(ii) decreases
(iii) remains same
(iv) none of above

36. Area under the daily load curve divided by 24 hrs gives
(i) units generated
(ii) average load
(iii) maximum demand
(iv) none of above

37. The maximum demand of a consumer is 2 kW and his daily energy consumption is 20 units. His load factor is a
(i) 50%
(ii) 60%
(iii) 41.6%
(iv) 35%

38. A base load station has a capacity of 18 MW. The annual output of the station is 101.35 x 106 kWh. The annual load factor of the station is
(i) 27.2%
(ii) 78.6%
(iii) 52.6%
(iv) 64.2%

39. The desirable qualities of the power system are
(i) high load factor and diversity factor
(ii) low load factor and diversity factor
(iii) low load factor and high diversity factor
(iv) high load factor and low diversity factor

40. Of all the plants, the minimum quantity of fuel required is in
(i) hydroelectric plant
(ii) thermal power plant
(iii) diesel plant
(iv) nuclear power plant

41. To supply base load of a power station, power plant is very suitable.
(i) diesel
(ii) nuclear
(iii) gas
(iv) none of above

42. A diesel power station is generally used as
(i) base load station
(ii) peak load station
(iii) both (i) and (ii)
(iv) none of above

43. The knowledge of diversity factor helps in determining
(i) average load
(ii) units generated
(iii) plant capacity
(iv) none of above

44. A diesel power station has fuel consumption of 0.28 kg per kWh, the calorific value of fuel being 10,000 kcal/kg. The overall efficiency of the station is
(i) 65.7%
(ii) 25%
(iii) 53.2%
(iv) 30.7%

45. The demand factor is generally
(i) less than 1
(ii) more than 1
(iii) equal to 1
(iv) none of above

46. If the maximum demand on the plant is equal to the plant capacity, then the value of load factor
(i) is equal to plant capacity factor
(ii) is less than plant capacity factor
(iii) is more than plant capacity factor
(iv) none of above

47. In a power system, diversity factor …….. as we move from consumers to power station.
(i) decreases
(ii) increases
(iii) remains same
(iv) none of above

48. The peak power supplied by peak load station is
(i) very cheap
(ii) very costly
(iii) same expensive as base load
(iv) none of above

49. Which of the following material is used as a moderator in nuclear power station?
(i) graphite
(ii) boron
(iii) calcium
(iv) plutonium

50. The cost of fuel transportation is minimum in
(i) hydroelectric plant
(ii) diesel plant
(iii) thermal plant
(iv) nuclear plant

51. In interconnected grid system, more efficient plants are used as
(i) peak load stations
(ii) base load stations
(iii) both (i) and (ii)
(iv) none of above

52. For low head and large discharge, the hydraulic turbine used is
(i) Francis turbine
(ii) Kaplan turbine
(iii) Pelton turbine
(iv) none of above

53. A diesel power station has fuel consumption pet day = 1000 k and units generated/day = 4000 kWh. The specific fuel consumption is
(i) 0.25 kg/kWh
(ii) 4 kg/kWh
(iii) 0.5 kg/kWh
(iv) none of above

54. To supply peak load of a power station, ………. power plant is very suitable.
(i) thermal
(ii) nuclear
(iii) diesel
(iv) none of above

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