Refractive Index

Q.

You are given water, mustard oil, glycerine, and kerosene. In which of these media a ray of light incident obliquely at the same angle would bend the most?

1. Kerosene

2. Water

3. Mustard Oil

4. Glycerine

Q. Why does the colour violet deviate the most and the colour red the least when white light passes through a triangular prism?

1. The colour violet has the longest wavelength, and the colour red has the shortest wavelength
2. Both violet and red have the same wavelength
3. None of the above
4. The colour violet has the shortest wavelength, and the colour red has the longest wavelength.

Q. The refractive indices of alcohol and turpentine oil with respect to air are 1.36 and 1.47respectively. Find the refractive index of turpentine oil with respect to alcohol. In which of the twomedia the speed of light will be more.

Q. Light travels slower in oil than in water because:​

1. Oil has less mass density than water​
2. Oil has more mass density than water ​
3. Oil has less optical density than water
4. Oil has more optical density than water

Q. If a light ray from air enters three different media in such a way that the refracted angles are ${45}^0$, ${30}^0$ and ${60}^0$ respectively. Identify the right statement with respect to the optical density of these media.

1. Optical density is highest for medium 3.

2. Optical density is highest for medium 2.

3. Optical density is least for medium 3.

4. Optical density is least for medium 2.

Q. If a light ray incidents normally on one of the faces of the prism of refractive index 2 and the emergent ray just grazes the second face of the prism then angle the angle of deviation i

Q. On a glass slab, a beam of light is incident at an angle of ${60}^{\circ }$. Few light rays get reflected and others get refracted. If the reflected and the refracted light rays are mutually perpendicular, calculate the refractive index of the glass slab.

Q. A man places a rectangular glass slab of thickness 9 cm on a newspaper. On the top of the glass slab he places a glass beaker of negligible wall thickness containing water up to a height of 6 cm. If refractive index of glass is 1.5 and refractive index of water is (4/3), what is the apparent depth of the newspaper?

Q. What is speed of light in vacuum? How does vacuum, force and air effects speed of light?

Q. When a ray of light travel from air to glass, it bends ___the normal.

1. 180 degrees
2. 90 degrees
3. away from
4. towards

Q. Which of the following statements is/are correct regarding refractive index?

1. It is the measure of the degree of bending of a light ray on change of medium.
2. It gives a measure of the speed of a light ray in a medium.
3. A higher refractive index means a higher speed of light in that medium.
4. An optically rarer medium has lower refractive index.

Q.

Petrol is less denser than water. Inspite of this it has greater optical density than water. Why?

Q. Draw a ray diagram to show that the depth of a vessel cotaining water when seen from above, appears to be less than its real depth.

Q. If light falls perpendicularly on a plane mirror, what will be the angle of reflection?

1. It will not reflect.
2. 45°
3. 90°
4. 0°

Q.

Choose the denser medium from the given figure:

1. Both medium has same refractive index

2. Medium 1 is denser, medium 2 is rarer

3. Can’t say

4. Medium 1 is rarer, medium 2 is denser

Q. When light passes from air to glass, it experiences a change of:

1. speed only
2. wavelength and speed
3. frequency only
4. frequency and speed

Q. When a ray of light enters turpentine oil from water, its speed will:

1. remain the same
2. increase
3. decrease
4. Data insufficient

Q. The light rays are falling on surfaces $S_1$, $S_2$, $S_3$ as shown in the figures.




The surfaces on which the angle of incidence will be equal to the angle of reflection is/are:

1. $S_2$ and $S_3$ only
2. Only $S_1$
3. All the three surfaces
4. $S_1$ and $S_2$ only

Q. 104.The refractive index of medium 2 with respect to medium 1 is

Q. Explain the terms optically rarer medium and optically denser medium with examples.

Q. A ray of light in passing from a transparent medium 1 to another transparent medium 2 speeds up. In this case, state whether the refractive index of medium 2 is $\underset{–}{}$ the refractive index of medium 1.

1. greater than
2. equal to
3. none of these
4. less than

Q. A tank is filled with benzene to a height of $120mm$. The apparent depth of a needle lying at a bottom of the tank is measured by a microscope to be $80mm$. The refractive index of benzene is

1. $3.5$
2. $4.5$
3. $1.5$
4. $2.5$

Q. A sound wave is travelling in a medium in which the velocity is $v$. It is incident in the second medium in which the velocity of the wave is $2v$. What should be the minimum angle of incidence in the first medium, so that the wave fails to cross the surface of separation of the two media?

1. ${45}^{\circ }$
2. ${15}^{\circ }$
3. ${30}^{\circ }$
4. ${60}^{\circ }$

Q. Light travel through a glass of thickness $t$ and refractive index $n$.If $c$ is the velocity of light in vacuum, the time taken by light to travel through the plate is:

Q. How does the speed of light determine the optical density of a medium?

Q. Define the following terms:
a) Optically rarer medium
b) Optically denser medium ​[2 marks]

Q. What is the angle of incidence when a ray is incident normally on a plane mirror?

1. 45 degrees
2. 0 degree
3. 30 degrees
4. 90 degrees

Q. Which medium will bend light more−glass or water? Why?