(a) The potential difference across the ends of a conductor is maintained by connecting a battery or a dry cell at the ends of the conductor.
(b) When 1 Joule of work is done to move a 1 Coulomb charge from one point to another, then the potential difference between the two points is said to be 1 Volt (V).
(c) According to Ohm's Law, the current flowing in a circuit is directly proportional to the applied potential difference.
Mathematical expression for Ohm's Law: or V = IR (Where 'R' is the constant of proportionality and is known as the resistance of the circuit)
(d) Unit of resistance is Ohm, denoted by the symbol .
(e) According to Ohm's law, V = IR
Hence, the resistance of the heater is .
Now, if the potential difference is changed to 220 V, then the current in the circuit =