In a double slit experiment, when a thin film of thickness t having refractive index μ. is introduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of t is
(λ is the wavelength of the light used) :
(1) λ/2(μ - 1)
(2) λ/(2μ - 1)
(3) 2λ/(μ - 1)
(4) λ/(μ - 1)
