Question

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Answer 1

Resistance ($R$) of a resistor is given by Ohm's law as, $V= IR$
$R= \frac VI$
Where,
Potential difference, $V= 12 \ V$
Current in the circuit, $I= 2.5 \ mA = 2.5 \times 10^{-3} A$
$𝑅= \frac {12}{2.5 \times 10^{-3}}$
$R = 4800\ Ω$
$R= 4.8 \ kΩ$

Therefore, the resistance of the resistor is $4.8\ kΩ$.