Question

An electric heater is rated 750 W – 200 V. Calculate (a) resistance of the heating element (b) current flowing through it.

Answer 1

P = 750 W; p.d. = 200 V; R = ?; I = ?

(a)\[\text{P} =\frac{\text{V}^{2}}{\text{R}}\]

\[\therefore \text{R}=\frac{\text{V}^{2}}{\text{P}}\]

\[=\frac{200 \times 200}{750}\]

= 53.33 Ω

(b) \[\text{R} = \frac{\text{V}}{\text{I}}\]

\[\therefore \text{I} = \frac{\text{V}}{\text{R}}\]

\[= \frac{200}{53.33}\]

= 3.75 A