Question

In Young’s double slit experiment the slits are separated by 0.28 mm and the screen is placed at a distance of 1.4 m away from the slits. The distance between the central bright fringe and the fifth dark fringe is measured to be 1.35 cm. Calculate the wavelength of the light used. Also find the fringe width if the screen is moved towards the slits, for the same experimental set up.

Answer 1

β = \(\frac{\lambda D}{d}\) Given the distance of the fifth dark fringe from the central bright fringe =1.35 cm

Wavelength of light used λ= 600 × 10^-9m; 

Taking distance between the slits and the screen as 1m 

Calculation of fringe width = 2.142 × 10^-3m