YDSE is conducted using light of wavelength `6000 Å` to observe an interference pattern. The slits are `2mm` apart. The fringes are observed on a screen `10cm` away from the slits. When a film of some material `0.5mm` thick was placed over one of the slits, the fringe pattern shifted by a `5mm`. What is the refractive index of the material of the film ?

Options

A. `1.2`
B. `1.5`
C. `1.8`
D. `4//3`

Answer

A