Question:

When a 12V 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.

Given: V = 12 V
I = 2.5 mA
Let the resistance be R
By Ohm's Law, V = IR
12 = 2.5 × 10⁻³ R
R = 4.8 × 10³ Ω