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.
[ 2 marks]
[NCERT Exercise]
[Ohm's law]

Answer 1

Solution:
Resistance (R) of a resistor is given by Ohm's law as,
V = IR
$R=\frac{V}{I}$ ( 1 Mark)
Where, potential difference, V = 12 V
Current in the circuit, $I=2.5mA=2.5\times {10}^{-3}A$
$R=\frac{12}{2.5\times {10}^{-3}}=4.8\times {10}^3\Omega =4.8k\Omega$ ( 1 Mark)
Therefore, the resistance of the resistor is $4.8k\Omega$.