In Young's double slit experiment the fringes are fomred at a distance of 1 m from double slit of separation 0.12 mm calculate.
(i). The distance of 3rd dard band from the centre of the screen.
(ii). The distance of 3rd bright band from the centre of the screen, Given `lamda=6000Å`

Explanation

For `m^(th)` dark fringe `x_m=(2m-1)(Dlamda)/(2d)`
given, D = 1 m = 100 cm, d = 0.12 mm = 0.012 cm
`x_m=((2times3-1)times100times6times10^-5)/(2times0.012)=1.25cm`
`[becausem=3 and lamda=6 times10^-5 cm]`