Answer : wavelength, λ = 1000 nm
Explanation :
It is given that,
Diffraction angle, [tex]\theta=30\ ^0[/tex]
The diffraction grating has 250 lines per mm\
For bright band the equation of grating is given by :
[tex]dsin\theta=n\lambda[/tex]
n = order, here n is 2
Since, d = 1/N
[tex]\lambda=\dfrac{sin\theta}{Nn}[/tex]
[tex]\lambda=\dfrac{sin(30)}{250000\ m\times 2}[/tex]
λ = 0.000001 m
or
λ = 1000 nm
So, the wavelength of the light is 1000 nm.
