Question

Keeping the p.d. constant, the resistance of a circuit is halved. The current will become:

(a) one-fourth
(b) four time
(c) half
(d) double

Answer 1

d) double

As we know from Ohm’s law:
Voltage = Current x Resistance
V = IR
If the voltage is constant, the resistance of the circuit is halved. That is, it becomes R / 2.
Current, I = V/R
I = V/R
I = V/R/2 = 2 I
Thus by keeping the p.d. constant, the resistance of a circuit is halved and the current is doubled.