Question

Which uses more energy 250W TV set in 1 hour or 1200W toaster in 10minutes

Answer 1

For T.V set

Power (P) = 250w, Time (t) = 1hr=60×60=3600s

For Toaster

Power (P) = 1200w, Time (t) = 10min=10×60=600s

We know that Energy (E) = P×t

∴ Energy consumed by a TV set = 250 × 3600 = 9 × 105J

∴ Energy consumed by a toaster = 1200 × 600 = 7.2× 105J

∴ the energy consumed by a 250 W TV set in 1 h is more than the energy

consumed by a toaster of power 1200 W in 10 minutes.

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.