Calculate the amount to heat produced per second when a bulb of 50W, 200V glows assuming that only 20% of the electric energy is converted into light.

20J

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40J

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50J

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200J

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Solution

The correct option is B 40J
Power of the bulb is $50$ W, this means that it consumes $50$ J of energy per second.
Electrical energy converted into heat $E_{H} = 0.8 E$
$∴$ $E_{H} = 0.8 \times 50 = 40$ J

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Calculate the amount to heat produced per second when a bulb of 50W, 200V glows assuming that only 20% of the electric energy is converted into light.

The correct option is B 40JPower of the bulb is 50 W, this means that it consumes 50 J of energy per second.Electrical energy converted into heat EH=0.8E∴ EH=0.8×50=40 J

The correct option is B 40J
Power of the bulb is $50$ W, this means that it consumes $50$ J of energy per second.
Electrical energy converted into heat $E_{H} = 0.8 E$
$∴$ $E_{H} = 0.8 \times 50 = 40$ J