Question

Which uses more enegry : a 250 W TV set in 1 hour or a 1200 W toaster in 10 minutes ?

Answer 1

For T.V set Power (P) = 250w, Time (t) = 1hr=60$\times$60=3600s
for toaster
power=1200W
time =10min = 10$\times$60 =600s
E=P$\times$T
Energy consumed by the TVset = 250$\times$3600 =9$\times$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.