Who will spend more electrical energy? 500 W TV set in 30 mins, or 600

1.	Who will spend more electrical energy? 500 W TV set in 30 mins, or 600 W heater in 20 mins?
Answer» Data : P₁ = 500 W, t₁ = 30 min = \(\frac{30}{60}\) h = \(\frac{1}{2}\) h, P₂ = 600 W, t₂ = 20 min = \(\frac{20}{60}\) h = \(\frac{1}{3}\) h Electrical energy used = Pt TV set : P₁t₁ = 500 W × \(\frac{1}{2}\) h = 250 W·h Heater : P₂t₂ = 600 W × \(\frac{1}{3}\) h = 200 W·h Thus, the TV set will spend more electrical energy than the heater.

Who will spend more electrical energy? 500 W TV set in 30 mins, or 600 W heater in 20 mins?

Answer»

Data : P₁ = 500 W, t₁ = 30 min = \(\frac{30}{60}\) h

= \(\frac{1}{2}\) h, P₂ = 600 W, t₂ = 20 min = \(\frac{20}{60}\) h = \(\frac{1}{3}\) h

Electrical energy used = Pt

TV set : P₁t₁ = 500 W × \(\frac{1}{2}\) h = 250 W·h

Heater : P₂t₂ = 600 W × \(\frac{1}{3}\) h = 200 W·h

Thus, the TV set will spend more electrical energy than the heater.