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

Explanation

We are given, potential difference V=60 V, current I = 4 A.
According to Ohm's law, `R=V/I=(60 V)/(4 V)=15 Omega`.
When the potential difference is tncreased to 120 V the current is given by
`"Current" =V/R=(120V)/(15Omega)=8 A`.
The current through the heater becomes 8 A.