The potential difference between the terminals of an electric heater is 60V when it draws a current of 4A from the source. What current will the heater draw if the potential difference is increased to 120V ?

Explanation

given Potential difference V=60 V, current I=4A
According to Ohm.s law, R=V/I=60/4=15`Omega`
When the potential difference is increased to 120V the current is given by current =V/R=120V/15=8A the current through the heater becomes 8A