Monochromatic light is incident on a grating that is 75 mm wide and ruled with 50,000 lines. the second-order maximum is seen at 32.5°. what is the wavelength of the incident light?

The wavelength of the incident light is 400 nm

Explanation:

Given data

Distance between the sits

d = 1.5 × m

°

m = 2

We know that the wavelength of the incident light is given by

Put all the value in above formula we get

×

4 × m

400 nm

Therefore the wavelength of the incident light is 400 nm

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.