Question

in single slit experiment explain clearly why the secondary maxima become weaker with increasing order (n) of secondary

maxima?

Answer 1

For single slit experiment intensity of maxima is given by
I = I₀ [{2sin(2n+1)π/2}/(2n+1)π]²
Here, I₀ is the intensity of slit , n is integers

For n = 0 ,
I₁= I₀[{2sin(π/2)}/π]² = 4I₀/π²

For n = 1
I₂= I₀ [{2sin(3π/2)}/3π]² = 4I₀/9π²

For n = 2
I₃= I₀[{2sin(5π/2)}/5π]² = 4I₀/25π²

Here what you see , I₃ < I₂ < I₁
It is clear that in increasing order of n , intensity of secondary maxima will be smaller .