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Question
Who will spend more electrical energy? 500 W TV Set in 30 mins, or 600 W heater in 20 mins?
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Solution
For T.V. set: Power = 500 W,
Time = 30 min = 30 × 60 s
∴ Energy = Power × time
E1 = 500 × 30 × 60 = 900 × 103 J
For Heater: Power = 600 W,
Time = 20 min = 20 × 60 s
∴ Energy (E2) = 600 × 20 × 60
= 720 × 103 J
Comparing E1 and E2, E1 > E2
∴ Energy spent by T.V. set (E1) is greater.
The energy consumed by the T.V. set is more than that consumed by the heater.
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