Huygens' Principle

Q. A wavefront at t= t sec is generated by taking the envelope of secondary wavelets from ___________ points on the wavefront at t=0 sec.

1. all
2. one
3. few
4. none

Q.

The wavefront at t=0 has moved to form the wavefront at t=t. The points C and D are a result of wavelets from:

1. No points on wavefront at t=0

2. All points on wavefront at t=0

3. B and A respectively

4. A and B respectively

Q.

The idea of secondary wavelets for the propagation of a wave was first given by

1. Fresnel

2. Newton

3. Huygen

4. Maxwell

Q. Huygen's principle of secondary wavelets may be used to

1. find the velocity of light in vacuum
2. explain the practical behaviour of light
3. find the new position of a wave front
4. explain Snell's law

Q. Who first proposed that light was wave-like in character ?

1. Newton
2. Maxwell
3. Huygens
4. Young

Q. Figure shows plane waves refracted from air to water using Huygen's principle a, b, c, d, e are lengths on the diagram. Find the ratio of refractive index of water w.r.t. air.

Q. Using Huygen's principle, obtain Snell's law of refraction.
An electron and a proton each have de Broglie wavelength of $1.00nm$
Find the ratio of their momenta

Q. If ${ϵ}_{o}and{\mu }_o$ are the electric permeability and magnetic permeability in free space $ϵand\mu$ are the corresponding quantities in a medium , then of refraction of the medium is

1. $\sqrt{\frac{{ϵ}_o{\mu }_o}{ϵ{\mu }_o}}$
2. $\sqrt{\frac{ϵ}{{ϵ}_o}}$
3. $\sqrt{\frac{ϵ\mu }{{ϵ}_o{\mu }_o}}$
4. $\sqrt{\frac{{ϵ}_o{\mu }_o}{ϵ\mu }}$

Q. (a) Define wave-front. Use Huygen's principle to verify the laws of refraction.
(b) How is linearly polarised light obtained by the process of scattering of light? Find the Brewster angle for air- glass interface, when the refractive index of glass $=1.5$.

Q. In the case of parallel beam,

1. intensity gradually increases
2. intensity gradually decreases
3. intensity remains constant
4. None of these