Household Electricity — Question 2

Power (P) = 1.5 kW

time (t) = 30 minutes = $\dfrac{\text{1}}{\text{2}}$ hr

(a) Electrical energy consumed in kWh= P x t
= 1.5 x $\dfrac{\text{1}}{\text{2}}$
= 0.75 kWh

So electrical energy consumed in kWh = 0.75 kWh

(b) 1 kWh = 3.6 x 10⁶ J

0.75 kWh = 0.75 x 3.6 x 10⁶

= 2.7 x 10⁶ J

So electrical energy consumed in joule = 2.7 x 10⁶ J.