Question

A heating element is marked $210V$, $630W$. Find the resistance of the element when connected to a $210V$ dc source.

Answer 1

Given: A heating element is marked $210V,630W$

To find the resistance of the element when connected to a $210V$ dc source.

Solution:

The power of the heating element is $630$ Watt and its voltage is $210V$. Thus, the current drawn can be calculated with the formula

$P=VI$,

where $P$ denotes the power, $V$ stands for the voltage and $I$ is the symbol of the current.

So the value of the current drawn $=\frac{P}{V}=\frac{630}{210}=3A$

And the resistance of the element when connected to a $210V$ dc source = $\frac{V}{I}=\frac{210}{3}=70\Omega$