Q130 / 180 · COMEDK 2017 · Physics

A piece of blue glass heated to a high temperature and a piece of red glass at room temperature are taken inside a dimly lit room. Then

  • A
    the blue piece will look blue and red will look as usual
  • B
    red will look brighter red and blue will look ordinary blue
  • Correct answer
    C
    blue will shines like brighter red compared to the red piece
  • D
    Both the pieces will look equally red

Solution

When blue glass is heated to a high temperature, it absorbs all radiations of higher wavelength except red. So, when it is taken inside a dimly lit room, it emits all radiations and hence looks brighter red compared to the red piece. This happens according to Kirchhoff's law of radiation.

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

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