Question

The following diagram is an arrangement to view the interference pattern produced by a wedge of liquid between a microscope slide and a glass block. The interference pattern obtained is made of equally spaced parallel fringes. The fringe separation (fringe width) may be decreased by some of the following actions.

• A. By decreasing the angle of liquid wedge.
• B. By using a liquid of higher refractive index.
• C. By using a thicker glass block
• D. By using a longer liquid wedge of the same angle

Answer 1

Answer: (A)

By decreasing the angle of liquid wedge.

Answer 2

Dx = 2mt = nl

t = x tan q

2mx tan q = nl

b = x_n+1 – x_n

b = $\frac{\lambda}{2\mu\tan\theta}$

as m increase b decrease.