Which device is used to convert electrical energy into mechanical energy?
(A) Electric generator
(B) Solenoid
(C) Electric motor
(D) Electric iron

Hint:In this question,we are going to study about the concept of conversion of energy from one form to another form.we have to examine each of the options one by one to find which device is used to convert electrical energy into mechanical energy.

Complete step by step answer:
Electric generator-:A generator is a device that transforms mechanical energy into electrical energy for use in an external circuit. Steam turbines, gas turbines, internal combustion engines, wind turbines and even hand cranks are some of the sources of mechanical energy.The theory of electromagnetic induction is being used on electric generators for operation.
Solenoid:The common name for a coil of wire used as an electromagnet is solenoid. It also refers to any system which uses solenoid to convert electrical energy to mechanical energy. The system produces a magnetic field from electrical current and induces linear motion using the magnetic field. Its main purpose is to generate a magnetic field.
Electric motor: An electric motor is an electrical device that converts electrical energy to mechanical energy. Many electric motors work to produce power in the form of torque applied to the motor’s shaft by the contact between the magnetic field of the motor and electrical current in a wire winding.
Electric iron:Electric iron is a device used on clothes to take out the wrinkling by pressing on the clothes while heated. Irons are made of plastic and metal in particular. The materials are in the shape of plastic resins, aluminium ingots and steel pipes. The metals are used to create the inner workings of the sole layer, thermostat and others.
Hence, from the above discussion we can conclude that electric motors are used to convert electrical energy into mechanical energy. Therefore, option C is correct.

Note:Here confusion may arise between the electric generator and electric motor as both appear the same. But an electric generator is used for converting mechanical to electrical energy while an electric motor used for converting electrical energy into mechanical energy