NEET Physics Question - Wave Optics - Young's Double Slit Experiment

Assertion (A): If width of one of the slit in YDSE is slightly increased, then maximum and minimum both Intensity will increase.

Reason (R): Intensity reaching from that slit on screen will slightly increase.

(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)

(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(3) (A) is true but (R) is false

(4) Both (A) and (R) are false

Solution:

In YDSE, the intensity of light from a slit is proportional to its width \(I \propto w\). Also, amplitude \(A \propto \sqrt{I}\). If one slit's width increases, its amplitude \(A\) increases. The maximum intensity is \(I_{max} = (A_1+A_2)^2\) and minimum intensity is \(I_{min} = (A_1-A_2)^2\). If \(A_1\) increases, both \(I_{max}\) and \(I_{min}\) will increase. Both A and R are true, and R explains A.

Rankers Physics

Slit Width and Intensity in YDSE

Solution:

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