Question

In Young’s double slit experiment, the distance between two slits is 0.8 mm and the fringes are observed 1m away. If it produces the second dark fringe at a distance of 1.5 mm from the middle position of central bright fringe. The wavelength of the monochromatic source of light used is 

(a) 600 nm 

(b) 500 nm 

(c) 450 nm 

(d) 480 nm

Answer 1

Correct option: (d) 480 nm

If β is fringe width, then spacing between second dark fringe and middle position of central bright fringe