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Power Generation

Study 121 Electrical Engineering MCQs with correct answers and explanations.

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1Electrical EngineeringMedium

In a boiler installation the natural draught is produced________?

Adue to the fact that furnace gases being light go through the chimney giving place to cold air from outside to rush in

Bdue to the fact that at the chimney top the pressure is more than its environmental pressure

Cdue to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column

Dall of the above

Correct answer

C. due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column

Explanation

The correct answer is due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column.

2Electrical EngineeringMedium

Which material is used to made a solar cell________?

Asilicon

Bscandium

CGermanium

Daluminum

Correct answer

A. silicon

Explanation

The correct answer is silicon.

3Electrical EngineeringMedium

Binary’vapour cycles are used to________?

Aincrease the efficiency of the plant

Bincrease efficiency of the turbine

Cincrease the performance of the condenser

Correct answer

A. increase the efficiency of the plant

Explanation

The correct answer is increase the efficiency of the plant.

4Electrical EngineeringMedium

The critical pressure ratio of a convergent nozzle is defined as________?

Athe ratio of inlet pressure to outlet pressure of nozzle

Bthe ratio of outlet pressure to inlet pressure only when mass flow rate per unit area is minimum

Cthe ratio of outlet pressure to inlet pressure of nozzle

Dthe ratio of outlet pressure to inlet pressure only when mass flow rate = c

Correct answer

D. the ratio of outlet pressure to inlet pressure only when mass flow rate = c

Explanation

The correct answer is the ratio of outlet pressure to inlet pressure only when mass flow rate = c.

5Electrical EngineeringMedium

A gas turbine basically work on

ADual cycle

BBrayton cycle

CCarnot cycle

DRankin cycle

Correct answer

B. Brayton cycle

Explanation

The correct answer is Brayton cycle.

6Electrical EngineeringMedium

Economisers improve boiler efficiency by________?

A4 to 10%

B10 to 12%

C1 to 5%

Correct answer

A. 4 to 10%

Explanation

The correct answer is 4 to 10%.

7Electrical EngineeringMedium

For forced draught system, the function of chimney is mainly________?

Anone of the above

Bto produce draught to accelerate the combustion of fuel

Cto discharge gases high up in the atmosphere to avoid hazard

Dto reduce the temperature of the hot gases discharged

Correct answer

C. to discharge gases high up in the atmosphere to avoid hazard

Explanation

The correct answer is to discharge gases high up in the atmosphere to avoid hazard.

8Electrical EngineeringMedium

The cooling section in the surface condenser________?

Areduces the quantity of vapour extracted along with air

Bdoes not affect vapour quantity extracted but reduces pump capacity of air extraction pump

Cincreases the quantity of vapour extracted along with air

Dnone of the above

Correct answer

A. reduces the quantity of vapour extracted along with air

Explanation

The correct answer is reduces the quantity of vapour extracted along with air.

9Electrical EngineeringMedium

The efficiency of chimney is approximately________?

A20%

B0.25%

C40%

D80%

Correct answer

B. 0.25%

Explanation

The correct answer is 0.25%.

10Electrical EngineeringMedium

Steam turbines commonly used in steam power station are________?

Anon-condensing type

Bnone of the above

Ccondensing type

Correct answer

C. condensing type

Explanation

The correct answer is condensing type.

In a boiler installation the natural draught is produced________?

Adue to the fact that furnace gases being light go through the chimney giving place to cold air from outside to rush in

Bdue to the fact that at the chimney top the pressure is more than its environmental pressure

Cdue to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column

Dall of the above

Correct answer

C. due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column

Explanation

The correct answer is due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column.

The critical pressure ratio of a convergent nozzle is defined as________?

Athe ratio of inlet pressure to outlet pressure of nozzle

Bthe ratio of outlet pressure to inlet pressure only when mass flow rate per unit area is minimum

Cthe ratio of outlet pressure to inlet pressure of nozzle

Dthe ratio of outlet pressure to inlet pressure only when mass flow rate = c

Correct answer

D. the ratio of outlet pressure to inlet pressure only when mass flow rate = c

Explanation

The correct answer is the ratio of outlet pressure to inlet pressure only when mass flow rate = c.

For forced draught system, the function of chimney is mainly________?

Anone of the above

Bto produce draught to accelerate the combustion of fuel

Cto discharge gases high up in the atmosphere to avoid hazard

Dto reduce the temperature of the hot gases discharged

Correct answer

C. to discharge gases high up in the atmosphere to avoid hazard

Explanation

The correct answer is to discharge gases high up in the atmosphere to avoid hazard.

The cooling section in the surface condenser________?

Areduces the quantity of vapour extracted along with air

Bdoes not affect vapour quantity extracted but reduces pump capacity of air extraction pump

Cincreases the quantity of vapour extracted along with air

Dnone of the above

Correct answer

A. reduces the quantity of vapour extracted along with air

Explanation

The correct answer is reduces the quantity of vapour extracted along with air.