an electric generator converts mechanical energy into electrical energy with an

Question

an electric generator converts mechanical energy into electrical energy with an efficiency of 96% and has a normal operating temperature of 350 k. does this violate the second law of thermodynamics? why?

1. no, the temperature of the environment may be very low.

2. yes, 96% is too large an efficiency to be obtained in a real world setting.

3. no, the generator runs by gathering the hidden energy of the electromagnetic field.

4. cannot be determined unless we know the temperatures involved.

5. yes, conversion of mechanical energy to electrical energy is an irreversible process, and creates entropy.

6. none of the other answers are correct.

7. no, electric generators do not have to obey conservation of energy.

8. yes, an engine operating between 350 k and 350 k should have an efficiency of zero.

9. no, the second law deals only with conversion of heat to work.

Explanation / Answer

For theoritcal efficiency, the engine operating between the two temperature must be involved.

4. cannot be determined unless we know the temperatures involved.

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