An interference fringe pattern is obtained in Fresnel's biprism, using sodium light of a mean wavelength of 589.3 nm. On introducing a thin sheet of a transparent material, having a thickness of 1.1 μm in the path of one of the interfering beams, the central bright fringe is found to shift through a distance equal to the spacing between the successive bright fringes. Then, the refractive index of the material of the transparent sheet is near:

An interference fringe pattern is obtained in Fresnel's biprism, using

1.	An interference fringe pattern is obtained in Fresnel's biprism, using sodium light of a mean wavelength of 589.3 nm. On introducing a thin sheet of a transparent material, having a thickness of 1.1 μm in the path of one of the interfering beams, the central bright fringe is found to shift through a distance equal to the spacing between the successive bright fringes. Then, the refractive index of the material of the transparent sheet is near:
A.	1.6
B.	1.62
C.	1.5
D.	1.54
Answer» E.