Whenever the magnetic field through a coil is changed,a potential difference is produced in the coil.

Name four appliances wherein an electric motor,a rotating device that converts electrical energy to mechanical energy,is used as an important component. In what respect are motors different from generators?

Name some devices in which electric motors are used.

The device used for producing electric current is called a

How is the induced current in a secondary coil related to the current in a primary coil?

Two coils $C_{1}$ and $C_{2}$ are wrapped around a non-conducting cylinder. Coil $C_{1}$ is connected to a battery and a key $K$,and coil $C_{2}$ is connected to a galvanometer $G$. On pressing the key $K$,current starts flowing in the coil $C_{1}$. State your observations in the galvanometer for the following cases:
$(i)$ When key $K$ is pressed on.
$(ii)$ When current in the coil $C_{1}$ is switched off.
$(iii)$ When the current is passed continuously through coil $C_{1}$.
$(iv)$ Name and state the phenomenon responsible for the above observation. Write the name of the rule that is used to determine the direction of the induced current.