Question

What is the wavelength in nm of a light whose first order bright band forms a diffraction angle of 30 degrees, and the diffraction grating has 700 lines per mm? ​

Answer 1

The wavelength is 3500 nm.

Step-by-step explanation:

d=
`(1)/(700 lines per mm) = 0.007mm = 7000 nm`

n= 1

θ= 30°

λ= unknown

Solution:

d sinθ = nλ

λ =
`(7000 nm sin 30)/(1)`

λ = 3500 nm