Question

If the resistance in a circuit connected to a constant current is halved, how is the voltage in the circuit affected?1. The voltage remains constant.2. The voltage is reduced by a factor of 4.3. The voltage is quadrupled.4. The voltage is reduced by a factor of 2.5. The voltage is doubled.

Answer 1

Answer:

4. The voltage is reduced by a factor of 2

Explanation:

The relationship between voltage, current and resistance in a circuit is given by Ohm's law:

V = RI

where

V is the voltage

R is the resistance

I is the current

In this problem,

the resistance in the circuit is halved: R' = R/2

the current is constant : I' = I

So the new voltage is

$V' = I' R' = I (\frac{R}{2})=\frac{1}{2} (IR) = \frac{V}{2}$

so the voltage is reduced by a factor 2.