Advertisements
Advertisements
प्रश्न
The velocity of light in a medium is 1.5 x 108 m/s. What is the refractive index of the medium with respect to air, if the velocity in air is 3 x 108 m/s?
उत्तर
Given that
`v_1=3xx10^8`
`v_2=1.5xx10^8`
We know that, the refractive index with respect to air is
`n=v_1/v_2`
`therefore n=(3xx10^8)/(1.5xx10^8)`
Thus, the refractive index of the medium with respect to air is 2.
APPEARS IN
संबंधित प्रश्न
If the refractive index of glass for light going from air to glass is 3/2, find the refractive index of air for light going from glass to air.
The absolute refractive indices of two media 'A' and 'B' are 2.0 and 1.5 respectively. If the speed of light in medium 'B' is 2 × 108 m/s, calculate the speed of light in:
(i) vacuum,
(ii) medium 'A'.
You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table.
Material medium |
Refractive index | Material medium | Refractive index |
Air | 1.0003 | Canada Balsam | 1.53 |
Ice | 1.31 | – | – |
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | – | – |
Kerosene | 1.44 | Carbon disulphide | 1.63 |
Fused quartz |
1.46 | Dense flint glass |
1.65 |
Turpentine oil | 1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
A ray of light travelling in water falls at right angles to the boundary of a parallel-sided glass block. The ray of light:
(a) is refracted towards the normal
(b) is refracted away from the normal
(c) does not get refracted
(d) is reflected along the same path
Which of the following diagrams shows the ray of light refracted correctly?
What is the unit of refractive index?
Which has higher refraction index : water of glass?
Give three examples of materials that refract light rays. What happens to the speed of light rays when they enter these materials?
Define Snell's law of refraction. A ray of light is incident on a glass slab at an angle of incidence of 60°. If the angle of refraction be 32.7°, calculate the refractive index of glass. (Given : sin 60° = 0.866, and sin 32.7° = 0.540).
What is the speed of light in a medium of refractive index `6/5` if its speed in air is 3,00,000 km/s?
The speed of light in water is 2.25 × 108 m/s. If the speed of light in vacuum be 3 × 108 m/s, calculate the refractive index of water.
State and explain the laws of refraction of light with the help of a labelled diagram.
Light travels through air at 300 million ms−1. On entering water it slows down to 225 million ms−1. Calculate the refractive index of water.
The refractive index of glass for light going from air to glass is .
The refractive index for light going from glass to air will be:
(a) `1/3`
(b) `4/5`
(c) `4/6`
(d) `5/2`
Refractive indices of four media A, B, C and D are given below:
Medium | Refractive index |
A | 1.33 |
B | 1.44 |
C | 1.52 |
D | 1.65 |
In which of these four media is the speed of light (i) maximum, and (ii) minimum?
State Snell’s law of refraction of light. Write an expression to relate refractive index of a medium with speed of light in vacuum.
The refractive index of a medium ‘a’ with respect to medium ‘b’ is 2/3 and the refractive index of medium ‘b’ with respect to medium ‘c’ is 4/3. Find the refractive index of medium ‘c’ with respect to medium ‘a’.
Mark the correct answer in the question.
If the refractive index of glass with respect to air is 3/2, what is the refractive index of air with respect to glass?
If in a medium, the speed of light is 1.5 × 108 m/s how much will the absolute refractive index of that medium be?
The velocity of light in a medium is 1.5 x 188 m/s. What is the refractive index of the medium with respect to air, if the velocity in the air is 3 x 108 m/s?
If the absolute refractive index of water is 1.36, find the speed of light in water. (Speed of light in vacuum = 3 × 108 m/s.)
If the absolute refractive index of glass and water are 3/2 and 4/3 respectively, what is the refractive index of glass with respect to water?
Solve the following example.
Speed in first medium, v1 = 3 × 108 m/s
Speed in second medium, v2 = 2 × 108 m/s
Then 2n1 = ?
Define the refractive index of a medium.
Light travel fastest in ______.
Noor, a young student, was trying to demonstrate some properties of light in her Science project work. She kept ‘X’ inside the box (as shown in the figure) and with the help of a laser pointer made light rays pass through the holes on one side of the box. She had a small butter-paper screen to see the spots of light being cast as they emerged.
She measured the angles of incidence for both the rays on the left side of the box to be 48.60. She knew the refractive index of the material ‘X’ inside the box was 1.5. What will be the approximate value of angle of refraction?
(use the value: sin 48.6° ≈ 0.75)
What happens when a light ray passes from a rarer medium to a denser medium?
The refractive index of glass with respect to air is `5/4` and the refractive index of water with respect to air is `4/3`. Then what will be the refractive index of glass with respect to water?
Match the pair:
Group 'A' | Group 'B' | |
Substance | Refractive index | |
Air | (a) | 1.33 |
(b) | 1.46 | |
(c) | 1.0003 |
Absolute refractive indices of diamond and water are 2.42 and 1.33 respectively. Find the value of refractive index of water w.r.t. diamond.
The ability of medium to refract light is expressed in terms of its optical density. Optical density has a definite connotation. It is not the same as mass density. On comparing two media, the one with the large refractive index is optically denser medium than the other. The other medium with a lower refractive index is optically rarer. Also the speed of light through a given medium is inversely proportional to its optical density. |
- Determine the speed of light in diamond if the refractive index of diamond with respect to vacuum is 2.42. Speed of light in vacuum is 3 × 108 m/s.
- Refractive indices of glass, water and carbon disulphide are 1.5, 1.33 and 1.62 respectively. If a ray of light is incident in these media at the same angle (say θ), then write the increasing order of the angle of refraction in these media.
- (A) The speed of light in glass is 2 × 108 m/s and is water is 2.25 × 108 m/s.
(a) Which one of the two optically denser and why?
(b) A ray of light is incident normally at the water glass interface when it enters a thick glass container filled with water. What will happen to the path of the ray after entering the glass? Give reason.
OR
(B) The absolute refractive indices of glass and water are 4/3 and 3/2, respectively. If the speed of light in glass is 2 × 108 m/s, calculate the speed of light in (i) vacuum (ii) water.
- Explain why the refractive index of any material with respect to air is always greater 1.
- In the figure below a light ray travels from air into the semi-circular plastic block. Give a reason why the ray does not deviate at the semi-circular boundary of the plastic block.
- Complete the ray diagram of the above scenario when the light ray comes out of the plastic block from the top flat end.
Absolute refractive indices of glass and water are `3/2 and 4/3` respectively. If the speed of light in glass is 2 × 108 m/s, the speed of light in water is ______.