Question

An electric heater consumes $4.4kW$ power when connected with a $220V$ line voltage then,
(i) Calculate the current passing through the heater.
(ii) Calculate the resistance of a heater.
(iii) Calculate the energy consumed in $2$ hours.

Answer 1

Given,

voltage $\left(V\right)=220V$
Power $\left(P\right)=4.4kW=4.4\times 1000W$
Time $t=2hr$

(i) $\therefore Current\left(I\right)=\frac{P}{V}$

$\Rightarrow I=\frac{4.4\times 1000}{220}=20A$

(ii) Resistance $\left(R\right)=\frac{V}{I}$

$\Rightarrow R=\frac{220}{20}=11\Omega$

(iii) Energy consumed in $2hrs,H=i^{2}Rt$

$\Rightarrow E=\left(20{)}^2\right(11\left)\right(2)=8800Whr=8.8kWhr$