Question

An AC generator is a device which converts
A. Electrical energy into mechanical energy.
B. Heat energy to electrical energy.
C. Heat energy to light energy.
D. Mechanical energy to electrical energy

Answer 1

Hint: Mechanical energy is equivalent to kinetic energy or potential energy. All forms of energy are convertible either from one form to another. For example, when the pendulum swings, then there is a constant conversion of Kinetic energy to potential energy or vice versa.

Complete answer:
As we know, an AC generator is a device that converts mechanical energy into electrical energy. It operates on the relationship between magnetism and electricity. It converts kinetic (mechanical) energy to electrical energy. Mostly the common method to produce electricity from generators with an electromagnet and a magnet produced by electricity.

We have seen that generators use a fuel to run that could be a conventional fuel that is either petrol or diesel. Hence generators have a mechanical shaft which rotates and cuts the magnetic lines similar to a brushless DC motor. When the Magnetic lines are kept on changing then due to electromagnetic induction, a current starts flowing when it is then responsible for electrical energy. Both phenomena are interrelated and connected to each other.

Hence, the correct answer is option (D).

Additional information:
Generator works on the principle of electromagnetic induction given by Faraday. If the magnetic fields are changed then electric current flows but when the electric field lines are changed then the magnetic field is generated.

Note: AC and DC generators both use electromagnetic induction to generate electricity. But AC generators produce an alternating current that periodically reverses the direction and DC flows only in one direction.