Question

Which uses more energy a 250W TV set in 1 h or a 1200W toaster in 10 minutes?

Answer 1

Power of TV set(P) =250W=0.25kW
Time(t) =1hr
Energy consumed =P×t
=0.25kW×1hr
=0.25kWhr
Power of toaster(P) =1200W=1.2kW
Time(t) =10 minutes =(10/60)hr=1/6 hr
Energy consumed=P×t
=1.2kW×1/6 hr
=0.2kWhr
So,energy consumed but set is more than that of energy consumed by the toaster.

Answer 2

⇒ Power (P) TV = 250 W

⇒ Time Taken (t) = 1 hr

⇒ Heat = Power × Time

⇒ H = Pt

⇒ 250 W × 1hr

⇒ 250 Wh

therefore , the energy consumed by 250 W TV set in 1 hr = 250 Wh.

⇒ Power (P) Toaster = 1200 W

⇒ Time Taken (t) = 10 minutes

⇒ H = Pt

⇒ 1200 × 10/60

⇒ 200 Wh.

Therefore, Energy consumed by TV set is more than by the toaster in the giving timing.