Question

The optical path difference between identical waves from two

coherent sources and arriving at a point is 87 wavelength. What can you

say about the resultant intensity at the point? If the path difference is

49.19 micrometer, calculate the wavelength of light.​

Answer 1

Answer:

The optical path difference between identical waves from two

coherent sources and arriving at a point is 87 wavelength. What can you

say about the resultant intensity at the point? If the path difference is

49.19 micrometer, calculate the wavelength light

Answer 2

the wavelength of light is 0.56 x $10^{-6}$m

Explanation:

arriving point = 87 wavelength

path difference =49.19 micrometer

resultant intensity = 4Icos²(Ф/2)

(where, Ф = 2π/λ = 2 x π/87)

now,

4Icos²(Ф/2) = 4Icos²(π/87)

optical path difference:

Δx  = 87λ

⇒ 49.19 x $10^{-6}$ = 87λ

⇒ λ = 49.19 x $10^{-6}$/87

λ = 0.56 x $10^{-6}$m

the point  87λ gives bright fringe

hence, the wavelength of light is 0.56 x $10^{-6}$m