Question

The resistance of filament of an electric heater is 500 Ω It is operated at 200V for 1 hour daily. Calculate the current drawn by the heater and the energy consumed in joule.

Answer 1

Given: R= 500 Ω, V = 200 volt.

Total time = t = 1 × 30h = 30h = 30 × 60 = 60 s = 108000s. 

Current drawn by the heater I = ${\displaystyle \frac{\text{V}}{\text{R}}=\frac{200}{500}=0.4}$ A

The energy consumed (in joule) = ${\displaystyle \frac{{\text{V}}^2}{\text{R}}\text{t}}$

${\displaystyle =\frac{{\left(200\right)}^2}{500}\times 108000}$

= 8640000 J.