CBSE Class 12-science Answered

when interference happens between two light waves , constructive interference occurs

if the path difference between two light waves is integer multiples of wavelength of light.

Let Δp is the path difference between light waves and λ is the wavelength of light , then we get constructive interference if

Δp = m λ

where m = 1,2,3,.............is positive integer ( m ≠ 0 ) .

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when interference happens between two light waves , destructive interference occurs

if the path difference between two light waves is odd integer multiples of half-wavelength of light.

Let Δp is the path difference between light waves and λ is the wavelength of light , then we get destructive interference if

Δp = (2m+1)  ( λ /2 )

where m = 0, 1,2,3,.............is positive integer  .

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Intensity of the light ray is directly proportional to the slit width. Therfore intensity of the light is more as the width of slit increases.