Question

State the principle of electric motor and electric generator.

Answer 1

Hint: An electric motor changes electrical energy into mechanical energy using an electromagnet at its core. An electric generator uses electromagnetic induction to convert mechanical energy into electrical energy.

Complete step by step solution:
An electric motor works on the principle that a current carrying conductor produces a magnetic field around it.
A simple electric motor comprises a wire coil, a permanent magnet, and a source of electric current- battery. The flow of current from the battery makes the coil an electromagnet. The electromagnet rotates because of the attractive and repulsive forces between the coil and the permanent magnet. The rotating coil causes a shaft to rotate, thus converting electrical energy into mechanical energy.

An electric generator works on the principle of electromagnetic induction, that is, electric current is generated by a changing magnetic field.
The mechanical energy provided from an external source rotates the turbine. The rotating turbine rotates the coil or the magnet of the generator. A current is induced in the coil because it is in a changing magnetic field, and thus, converting mechanical energy to electrical energy.

Additional information: In 1820, Hans Oersted, a Danish physics teacher, hypothesized that the current-carrying conductor produces a magnetic field around it and the direction of magnetic field depends on the direction of current. The direction of the magnetic field reverses on reversing the current in a conductor.

Note: Both electric motor and electric generator use electromagnets, but electric motor produces magnetic field due to flow of current and generator produces current due to changing magnetic field.