Question

An electrical heater is rated \(1000 \mathrm{~W}-200 \mathrm{~V}\). Calculate:

1. the resistance of the heating element.
2. the current flowing through it.

Answer 1

Given: \(P=1000\ \mathrm{W}\)

\(V=200\ \mathrm{V}\)

(i) Resistance:

\[R=\frac{V^2}{P}=\frac{200^2}{1000}=40\ \Omega\]

\[=\frac{200^2}{1000}\]

\[=\frac{40000}{1000}\]

\[=40\ \Omega\]

(ii) Current:

\[I=\frac{P}{V}\]

\[=\frac{1000}{200}\]

= 5 A