Question

An electric heater of power $1000$ watt is joined to electric mains of $250$ volt. Calculate:
(i) Electric current flowing through heater
(ii) Resistance of heater wire
(iii) Thermal energy produced per minute by heater
(iv) The electric energy spent in Kilowatt-hour by heater in $2$ hours.

Answer 1

Power $=P=VI⟹1000=250I⟹I=\frac{1000}{250}=4A$

$\therefore \left(i\right)$ Electric current flowing through heater$=I=4A$

$\therefore \left(ii\right)$ Resistance of heated wire $R=\frac{V}{I}=\frac{250}{4}=62.5\Omega$

$\therefore \left(iii\right)$ Thermal energy produced per minute by heater$=E_T=P\times 1min=1000\times 60sec=60000J$

$\therefore \left(iv\right)$ Electrical energy spent in kilowatt-hour by heater in 2 hours$=\frac{P}{1000}KW\times 2hour=2KW$-$hour$