Question

A thin perfectly transparent glass sheet of thickness t and refractive index mu is pasted on one of the two identical slits. If the intensity of light at the centre of the screen is `I_(0)` in the absence of glass sheet, the intensity at O as a function of thickness of the glass plate is
A. `I_(0)cos((mut)/lambda)`
B. `I_(0)cos^(2)((mut)/lambda)`
C. `I_(0)cos^(2)((pi(mu-I)t)/lambda)`
D. `I_(0)cos((pi(mu-I)t)/lambda)`

Answer 1

Correct Answer - C
`S_(1)O-S_(2)O=(mu-1)t`
`Deltaphi=(2pi)/lambda(mu-1)t`
`I=I_(max)cos^(2)(Deltaphi//2)`
`:.I=I_(0)cos^(2)((pi(mu-1)t)/lambda)`