Note : In the following questions a statement of Assertion (A) fo… - Vidyadip

MCQ

Note : In the following questions a statement of Assertion $(A)$ followed by a statement of Reason $(R)$ is given. Choose the correct option out of the choices given below each question.
Assertion $(A)$ : Black body is an ideal body that emits and absorbs radiations of all frequencies.
Reason $(R)$ : The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.

A
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
✓
$A$ is true but $R$ is false.
C
$A$ is false but $R$ is true.
D
Both $A$ and $R$ are false.

✓

Answer

Correct option: B.

$A$ is true but $R$ is false.

The ideal body, which emits and absorbs radiations of all frequencies, is called a black body and the radiation emitted by such a body is called black body radiation. The exact frequency distribution of the emitted eadiation $($i.e. intensity versus frequency curve of the radiation$)$ from a black body depends only on its temperature. At a given temperature, intensity of radiation emitted increases with decrease of wavelength, reaches a maximum value at a given wavelength and then starts decreasing with further decrease of wavelength.

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