Question

An electric circuit consists of a variable resistor connected to a source of constant potential difference. If the resistance of the resistor is doubled, the current through the resistor is: a) halved doubled b) quartered c) quadrupled.

Answer 1

Answer:

The correct option is a) halved

Therefore,

Current through the resistor will be halved i.e

$I'=\dfrac{1}{2}\times I$

Explanation:

Given:

V = Voltage potential Difference constant

R' = 2R

To Find:

Current, I' = ? when R' = 2R

Solution:

Ohm's law:

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

Ohm's law given as

$Voltage=Current\times Resistance\\V=IR$

$I=\dfrac{V}{R}$

Substituting the R' = 2R , new current we get

$I'=\dfrac{V}{R'}=\dfrac{V}{2R}=\dfrac{1}{2}\times \dfrac{V}{R}=\dfrac{1}{2}\times I$

Therefore,

Current through the resistor will be halved i.e

$I'=\dfrac{1}{2}\times I$