Reflection of Light

Q.

Why the central fringe is dark in Newtons ring?

Q. A ray of light is incident on a plane mirror along a vector $(\hat{i}+\hat{j}-\hat{k})$. The normal on the incident point is along $\left(\hat{k}\right)$. The unit vector along the reflected ray will be:

1. $\frac{1}{\sqrt{2}}(\hat{i}+\hat{j}-\hat{k})$
2. $\frac{-1}{\sqrt{3}}(\hat{i}+\hat{j}+\hat{k})$
3. $-\hat{i}-\hat{j}$
4. $\frac{1}{\sqrt{3}}(\hat{i}+\hat{j}+\hat{k})$

Q. A ray of light is incident on a plane mirror along a vector $(\hat{i}+\hat{j}-\hat{k}).$ The normal on incident point is along $(\hat{i}+\hat{j}).$ The unit vector along the reflected ray is

1. $-\frac{1}{\sqrt{3}}(\hat{i}+\hat{j}+\hat{k})$
2. $\frac{1}{\sqrt{3}}(-\hat{i}-\hat{j}+\hat{k})$
3. $\frac{(\hat{i}-\hat{j}-\hat{k})}{\sqrt{3}}$
4. $\frac{1}{\sqrt{3}}(\hat{i}+\hat{j}+\hat{k})$

Q. Identify the incorrect statement regarding the reflection of light from a plane mirror when a light ray is incident obliquely. $\overrightarrow{R},\overrightarrow{I}$ and $\overrightarrow{N}$ represents the vectors along the reflected ray, incident ray and normal direction.

1. $\overrightarrow{R}.(\overrightarrow{I}\times \overrightarrow{N})=0$
2. $\overrightarrow{N}.(\overrightarrow{I}\times \overrightarrow{R})=0$
3. $\overrightarrow{I}.(\overrightarrow{N}\times \overrightarrow{R})=0$
4. $\overrightarrow{N}\times \overrightarrow{I}=0$

Q. A ray of light is approaching a set of three mirrors as shown in the diagram. The light ray is approaching the first mirror at an angle of ${45}^{\circ }$ with the mirror surface. How many times will the ray reflect before it exits the system?

1. $1$
2. $2$
3. $3$
4. $4$

Q. When light wave suffers reflection at the interface from air to glass, the change in phase of the reflected wave is equal to: a. Zero b.2π c. π d. 2π

Q. The image of point 'P' when viewed from top of the slab combination, will be formed at position.

1. 1.5 cm above P
2. 2 cm above P
3. 1 cm above P
4. 2 cm below P

Q. If the incident ray is rotated by an angle of ${30}^{\circ }$ while the plane mirror is at rest, the reflected ray gets rotated by .

1. ${30}^{\circ }$
2. ${90}^{\circ }$
3. $0^{\circ }$
4. ${60}^{\circ }$

Q. When the angle of incidence is ${60}^{\circ }$ on the surface of a glass slab, it is found that the reflected ray is completely polarized. The velocity of light in glass is,

1. $\sqrt{3}\times {10}^8{\text{ms}}^{-1}$
2. $2\times {10}^8{\text{ms}}^{-1}$
3. $\sqrt{2}\times {10}^8{\text{ms}}^{-1}$
4. $3\times {10}^8{\text{ms}}^{-1}$

Q. If the incident ray is rotated by an angle of ${30}^{\circ }$ while the plane mirror is at rest, the reflected ray gets rotated by .

1. ${30}^{\circ }$
2. ${90}^{\circ }$
3. $0^{\circ }$
4. ${60}^{\circ }$

Q.

A ray of light is incidenting normally on a plane mirror. The angle of reflection will be

1. 

2. 
3. Will not be reflected

4. None of the above