Question

A shift of 100 circular fringes are observed when the movable mirror of Michelsons interferometer is shifted by 0.0 295 mm calculate the wavelength of light.​

Answer 1

Answer:

A shift of one fringe corresponds to a change in the optical path length of one wavelength. When the mirror moves a distance d, the path length changes by 2d since the light traverses the mirroe arm twice. Let N be the number of fringes shifted. Then, 2d=Nλ and

λ=

N

2d

=

792

2(0.233×10

−3

m)

=588×10

−7

m=588 nm

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