written 6.9 years ago by | modified 2.9 years ago by |
Subject: Applied Physics 2
Topic: Interference And Diffraction Of Light
Difficulty: High
written 6.9 years ago by | modified 2.9 years ago by |
Subject: Applied Physics 2
Topic: Interference And Diffraction Of Light
Difficulty: High
written 6.8 years ago by |
i) with the increase in number of lines the secondary maxima relative to the principal maxima decreases and becomes negligible. The principal maxima become more sharp and intense.
ii) we know (a+b) sinθ = nλ
For the first order minima ,Sinθ =λ/(a+b)
If a+b = λ, then
Sinθ = 1 or θ =90°
Thus, a theoretical limit is reached the first order maximum will not be visible.
If (a+b) <λ sinθ becomes greater than 1, which is not possible. Hence no spectrum is formed and the grating is rendered useless.
iii) If the rulings are made closer, the angular spacing between the maxima increases.