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Question
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
Solution
Energy consumed by an electrical appliance is given by the expression, H = Pt
Where,
Energy consumed by a TV set of power p = 250 W in 1 h = 250
Time, t = 1 hr = 3600 sec
H = P × t
= 250 × 3600
= 900000
H = 900000 J
Energy consumed by a toaster of power 1200 W
Time, t = 10 minutes = 600 sec
H = P × t
= 1200 × 600
= 720000
H = 720000 J
Therefore, the energy consumed by a 250 W TV set in 1 hour is more than the energy consumed by a toaster of 1200 W in 10 minutes.
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