Question

A $4kW$ heater is connected to a $220V$source of power. Calculate

ii. the resistance of the heater

Answer 1

Step 1- Given Data and formulas

The power rating of the heater $P=4kW$

The voltage applied $V=220V$

Electric power in terms of the voltage applied and resistance is given by

$P=\frac{V^2}{R}$

where $R$ is the resistance.

Step 2: Finding the resistance of the heater

Substitute the known values in the equation

$$\begin{gathered} 4kW\times \frac{1000W}{1kW}=\frac{{(220V)}^2}{R} \\ R=\frac{{220}^2}{4000} \\ R=12.1\Omega \end{gathered}$$

Final answer: The resistance of the heater is $12.1\Omega$.