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

Question 16:

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

Answer:

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.