Q: In young’s double slit experiment the co-ordinates of central maxima and 10th maximum are 2 cm and 5 cm respectively. When the YDSE apparatus is immersed in a liquid of refractive index 1.5 the corresponding y co-ordinates will be

Sol: Fringe width β ∝ λ. Therefore, λ and hence β will decreases 1. 5 times when immersed in liquid. The

distance between central maxima and 10th maxima is 3 cm in vacuum. When immersed in liquid it will

reduce to 2 cm. Position of central maxima will not change while 10th maxima will be obtained at y = 4

cm.