Question

The current in the wires of a circuit is 90 milliAmps. If the resistance of the circuit were doubled (with no change in voltage), then its new current would be _____ milliAmps.

Answer 1

Answer:

$I = 45mA$

Explanation:

Given

$I = 90mA$ --- Current

Required

Determine the new current when resistance is doubled

Using $V = IR$

Initially, we have:

$V = 90mA * R$

When resistance is doubled and voltage remains unaltered, we have:

$V = I* 2R$

2R represents the new resistance and I represents the new current

Equate both values of V

$90mA * R = I* 2R$

Make I the subject

$I = \frac{90mA * R}{2R}$

$I = \frac{90mA }{2}$

$I = 45mA$

The new current is 45milliAmps