Question

Laser light of wavelength 630 mm incident on a pair of slits produces as interference pattern in which the bright fringes are separated by 8.1 mm. A second light produces an interference pattern in which the fringes are separated by 7.2 mm. Calculate the wavelength of the second light.

Answer 1

Fringe separation is given by `beta=(lamdaD)/(d)`
I.e., `(beta_(2))/(beta_(1))=(lamda_(2))/(lamda_(1))implieslamda_(2)=(beta_(2))/(beta_(1))xxlamda_(1)=(7.2)/(8.1)xx630=560mm`