Optics Question 195

Question: The light of wavelength $ 6328{AA} $ is incident on a slit of width 0.2 mm perpendicularly, the angular width of central maxima will be

[MP PMT 1987; Pb. PMT 2002]

Options:

A) $ {{0.36}^{o}} $

B) $ {{0.18}^{o}} $

C) $ {{0.72}^{o}} $

D) $ {{0.09}^{o}} $

Show Answer

Answer:

Correct Answer: A

Solution:

The angular half width of the central maxima is given by $ \sin \theta =\frac{\lambda }{a} $

$ \Rightarrow \theta =\frac{6328\times {{10}^{-10}}}{0.2\times {{10}^{-3}}} $ rad $ =\frac{6328\times {{10}^{-10}}\times 80}{0.2\times {{10}^{-3}}\times \pi } $ degree = 0.18o

Total width of central maxima $ =2\theta ={{0.36}^{o}} $



NCERT Chapter Video Solution

Dual Pane