Question

100J of heat are produced each second in a 4 ohm resistance . Find the potential difference across the resisters.

Answer 1

Amount of heat=work done by the resistor

Work=100J

But work=V^2/R*t

where V=potential difference,R is the resistance and t=time.

Considering t=1s

100=V^2/4*1

=V^2=400

=V=√400

=V=20 or V=-20

but potential difference should not be negative.

So V=20v