One leg of a michelson interferometer contains an evacuated cylinder of length l, having glass plates on each end. a gas is slowly leaked into the cylinder until a pressure of 1 atm is reached. if n bright fringes pass on the screen when light of wavelength λ is used, provide an expression for the index of refraction of the gas?
hint: the fringe shifts occur because the wavelength of the light changes inside the gas-filled tube.

Explanation:

Due to  change in the refractive index of the medium , wavelength changes. If λ  be wave length in vacuum ,  wave-length in refractive index μ

will become  λ / μ

Initially no of wavelengths in length L were  L / λ

Finally no of wavelengths in length L were L / λ / μ = Lμ / λ

Given

Lμ / λ  -  L / λ  = N

L / λ ( μ -1 ) = N

μ = ( Nλ / L + 1 )

the moon affects the earth gravitation ally, causing certain motions of that body and also producing tides in its ocean and atmosphere. the tidal wave in our atmosphere is, however, far too minute to be an effective cause in any known meteorological phenomenon.

explanation:

the total distance traveled by the car is

30km + 49km = 79 km .