$(a)$ When do we state that an electrical appliance is earthed? Mention the function of the earth wire in electric lines. Why is it necessary to earth electric appliances having a metallic body?
$(b)$ Explain what is short-circuiting and overloading in an electric supply.

(N/A) An electrical appliance is said to be earthed when its metallic body is connected to a metal wire which is buried deep inside the earth. The function of the earth wire is to provide a low-resistance path for the current to flow into the ground in case of a leakage,thereby preventing electric shocks. It is necessary to earth appliances with metallic bodies because if a live wire touches the metal casing,the current flows to the earth instead of passing through the user,thus ensuring safety.
$(b)$ $(i)$ Short-circuiting: This occurs when the live wire and the neutral wire come into direct contact with each other,leading to a sudden surge in current.
$(ii)$ Overloading: This occurs when too many electrical appliances are connected to a single socket or circuit,exceeding the rated capacity of the wires,which can cause overheating.