Question

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?

Answer 1

The wavelength of the incident light is
`\lambda =` 400 nm

Step-by-step explanation:

Given data

Distance between the sits

`d = (0.075)/(50000)`

d = 1.5 ×
`10^(-6)` m

`\theta = 32.5`°

m = 2

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

`\lambda = (d\sin \theta)/(m)`

Put all the value in above formula we get

`\lambda = (1.5 (\sin 32.5))/(2)`×
`10^(-6)`

`\lambda =` 4 ×
`10^(-7)` m

`\lambda =` 400 nm

Therefore the wavelength of the incident light is
`\lambda =` 400 nm