Question

For a heater rated at $4kW$; $220V$ . Calculate the resistance of the heater element.

• A. $20\Omega$
• B. $21.6\Omega$
• C. $200\Omega$
• D. $12.2\Omega$

Answer 1

The correct option is D $12.2\Omega$

Given: $V=220$ volts $P=4000$ W

Electric power is given by

$P=\frac{V^2}{R}$ where $R$ is resistance and $V$ is voltage.

$\therefore$ Resistance of the heater $R=\frac{V^2}{P}=\frac{{220}^2}{4000}=12.1\Omega$