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An LED has two legs of unequal length. For the LED to glow in a circuit, its
Study circuits X and Y. In which circuit will the LED glow? Give a reason.
An incandescent bulb and an LED give the same amount of light. After an hour, the incandescent bulb is too hot to touch but the LED is only slightly warm. What does this tell us about which one uses electricity better?
Seema says, 'An LED lamp is costly to buy, so an incandescent bulb is the better choice for our home.' Do you agree? Give three reasons for your answer.
A school had 20 incandescent bulbs of 60 W each in its classrooms. The principal replaced all of them with 20 LED lamps of 9 W each, which give about the same light. The lights are used for 6 hours a day. Energy in units = (power in watts × time in hours) ÷ 1000.
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