Q112 / 180 · AIIMS 2006 · Physics

Flash light equipped with a new set of batteries, produces bright white light. As the batteries wear out,

  • A
    the light intensity gets reduced with no change in its colour
  • B
    light colour changes first to yellow and then red with no change in intensity
  • C
    it stops working suddenly while giving white light
  • Correct answer
    D
    colour changes to red and also intensity gets reduced.

Solution

If the voltage is not sufficient to heat it to white hot temperature, the filament will become red. But the intensity will be very much reduced because of low voltage. But if the voltage is only reduced a little only intensity will be reduced. It can be (1) also.

Hence, the correct answer is option: 'D'.

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