Q : In young’s double slit experiment the two slits are illuminated by light of wavelength 5890°A and the distance between the fringes obtained on the screen is 0.2°. If the whole apparatus is immersed in water then the angular fringe width will be, if the refractive index of water is 4/3
(a) 0.30°
(b) 0.15°
(c) 15°
(d) 30°
Ans: (b)
Sol:
Angular Width $ \displaystyle \theta ‘ = \frac{\theta}{\mu} $
$ \displaystyle \theta ‘ = \frac{0.2}{4/3} $
$ \displaystyle = \frac{0.6}{4} $
= 0.15°