Question

What would be your specifications for the plane diffraction grating to view the mercury spectral line 577nm of the third order? Explain

Answer 1

As per the question,

A large number of narrow rectangular slits having width in the order of the wave length of light and arranged side by side with equal opaque spaces is called a plane transmission diffraction grating. It is an extension of diffraction due to double slit.

wavelength of wave is given $(\lambda)=577nm$

m=3

We know that $d\sin \theta=m\lambda$

$\Rightarrow d\sin \theta=577\times 10^{-9}\times 3m$

$\Rightarrow d\sin\theta=1731\times 10^{-9}m$

$d\sin \theta=1.731\times 10^{-6}m$

$d\sin \theta=1.731\mu m$