1) In Young's double slit experiment the two slits are illuminated by light of wavclenght 5890Å and the distance between the fringes obtained on the screen is 0.2º. 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) 0.30º B) 0.15º C) 15º D) 30º Answer: Option BExplanation:Wa = λ/d → Wa αλ $\frac{(W_{a})Water}{W_{a}}$ = $\frac{\lambda_{Water}}{\lambda}$ = $\frac{\lambda}{\mu_{Water}\lambda}$ $(W_{a})Water$ = $\frac{2\times3}{4}$ = 0.15º
