An electric fan converts,
A. electrical energy into chemical energy
B. electrical energy into mechanical energy
C. electrical energy into light energy
D. mechanical energy into electrical energy

Hint: As we know that energy conversion which is also known as the energy transformation, is defined as the process of changing or conversion from one form of energy into another. Conversion of energy occurs everywhere and every time around us.

Complete answer:
We are aware of the fact that thermodynamics is the study of energy and the process of its conversion from one form to another.
According to the first law of thermodynamics, energy can neither be created nor destroyed, it can only be transformed from one form to another. It is also known as the law of conservation of energy, which states that when the energy is transferred or transformed from one form to another then the total amount of energy before and after the conversion remains the same.
An electrical energy is defined as the energy which is said to be derived from electric potential energy or kinetic energy.
While mechanical energy is the energy which is possessed by an object because of its motion or its position.
We know that an electric fan as the name suggests runs with electricity and it functions due to mechanical energy i.e. its rotational motion.
Thus, an electric fan converts an electrical energy into mechanical energy.

Hence, option (B) is the correct answer.

Note:
In physics, energy is known as the capacity of a body to do work. There are various forms of energy such as thermal energy, light energy, electrical energy, nuclear energy, electromagnetic energy, mechanical energy, chemical energy, sound energy etc.