Question

The potential difference between the terminals of an electric heater is 60V 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.

Answer 1

V=IR
V is proportional to I
If the potential difference is doubled then current will be doubled because the resistance is constant in this case. The current is 8 A.

Answer 2

pot.D.(1)-60V
I(1)- 4A
from Ohms law
V=IR then
R=V/I
putting the values
R=60/4
=15Ohms
the resistance of the heater will not change if the amount of voltage is changed
now V =120volt
R=15ohms
from Ohms law V=IR
I=V/R
=120/15
=8A
the answer is 8A
hope my answer helped you.