Question

Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. The resistance of each heater is :

• A. $40\Omega$
• B. $25\Omega$
• C. $2.5\Omega$
• D. $25000\Omega$

Answer 1

The correct option is A $40\Omega$

Power is given as: $P=VI$

Substituting, $I=\frac{V}{R}$ in the above formula, we get, $P=\frac{V^2}{R}$

Given that the voltage is $250V$ and the power is $60W$, the resistance of the bulb is calculated as follows.

$R=\frac{V^2}{P}=\frac{{100}^2}{250}=40\Omega$