Q106 / 180 · AIIMS 2007 · Physics

Assertion : A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation. Reason : All metals act as black bodies.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • C
    If assertion is true but reason is false
  • Correct answer
    D
    If both assertion and reason are false.

Solution

A hollow metallic container with a small orifice and coated with lamp black inside is taken as a source of black-body radiation when it is heated. A closed container cannot act as a source of blackbody because it cannot absorb all radiations. All metals are not black bodies. A black body is described above. It is the hole that absorbs and emits the radiation, which is treated as a black body and not even the whole container. Assertion is only partially correct.

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

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