Question

If is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled?

Answer 1

Hello dear,

● Answer -
I' = 4I

● Explaination -
Intensity of principal maximum is directly proportional to square of slit width.
I ∝ W^2
I'/I = (W'/W)^2

Given that W' = 2W,
I'/I = (2W/W)^2
I'/I = 2^2
I'/I = 4
I' = 4I

Therefore, intensity of principal maximum will be quadrupled if slit width is doubled.

Hope this helps you..

Answer 2

The intensity is I = Io  x  (   π a sinθ /   λ   )^2  / ( π a sinθ /   λ  )  ^2  

Explanation:

Given data:

• Intensity of teh principal maximum at screen is given by:
• I = Io  x  (   π a sinθ /   λ   )^2  / ( π a sinθ /   λ  )  ^2  
• Where a is the size of the slit.
• θ =  angle subtended by interfering light ray on screen.

For principal maxima- (θ→0)    [ At the central]

I ( central)  = Io

​It is Independent of slit size "a".