# Refractive Index of a Glass Slab Viva Questions

Refractive Index of a Glass Slab Using Travelling Microscope Viva Questions and Answers

(i) What is meant by the refractive index of the material of a transparent medium?

Ans: Refractive index is called as the measure of the bending of a light ray when passing from one medium to another.

(ii) Give the relation for the refractive index of a medium in terms of velocity of light.

Ans: n = c/v, where n is refractive index, c is velocity of light and v is velocity of substance.

(iii) What is Snell's law of refraction?

Ans: Snell's law is a formula that defines the relationship between angles of incidence and refraction. The mathematical formula is given below.

n1sinθ1 = n2sinθ2

(iv) Give an equation for the refractive index of a glass slab in terms of real and apparent thicknesses of a glass slab.

(v) What is meant by shift in the position of image produce by a glass slab?

(vi) Aim of the refractive index of a glass slab Experiment?

Ans: To determine the refractive index of the material of a glass slab.

(vii) Apparatus of the refractive index of a glass slab Experiment?

Ans: The glass slab, a travelling microscope, chalk powder, etc.

(viii) Theory of the refractive index of a glass slab Experiment?

Ans: The refractive index of the material of the glass slab is given by,
μ = Real thickness of the glass slab/ Apparent thickness of the glass slab

(ix) Procedure of the refractive index of a glass slab Experiment?

Ans: A few small grains of chalk power is sprinkled on the horizontal base of the travelling microscope. The microscope is kept vertically and adjusted to get a well focussed image of the chalk powder. The reading R1 of the microscope is taken on its vertical scale. The glass slab is placed over the chalk powder. The microscope is raised and adjusted to get the image of the chalk powder. The microscopic reading R2 is again taken. The chalk powder is sprinkled over the glass slab. The microscope is raised further to get the chalk powder focussed. The reading R3 of the microscope is noted. The real thickness of the glass slab,

t = R3 - R1

The apparent thickness of the glass slab,

t' = R3 - R2

The refractive index of the material of the glass slab is calculated by the equation,

μ = Real thickness /Apparent thickness = t/ t' = (R3 - R1)/(R3 - R2).