Assertion (A) : The maximum intensity in interference pattern is four times the intensity in interference pattern is four times the intensity due to each slit of equal width.
Reason (R ) : Intensity is directly proportinal to square of amplitude.

Options

A. (a) If both assertion and reason are true and reason is the correct explanation of assertion.
B. (b) If both assertion and reason are true but reason is not the correct explanation of assertion.
C. (c) If assertion is true but reason is false.
D. (d) If assertion and reason both are false.

Answer

B

Explanation

Let a be the amplitude of waves from each slit. Intensity is directly proportional to square of amplitude i.e, `Ipropa^2`.
Due to each slit `I_1propa^2`
When destructive interference occurs, then resultant amplitude `=a-a=0`
`:.` Minimum intensity, `I_(min)=0`
When constructive interference occurs, the resultant amplitude `=a+a=2a`
`:.` Maximum intensity, `I_(max)prop(2a)^2`
Hence, `I_(max)prop4a^2`
or `I_(max)=4` times the intensity due to each slit.