Advertisements
Advertisements
Question
The speed of light in vacuum and in two different glasses is given in the table below:
| Medium | Speed of light |
| Vacuum | 3.00 × 108 m/s |
| Flint glass | 1.86 × 108 m/s |
| Crown glass | 1.97 × 108 m/s |
(a) Calculate the absolute refractive indexes of flint glass and crown glass.
(b) Calculate the relative refractive index for light going from crown glass to flint glass.
Solution
(a) Absolute refractive index of flint glass = Speed of light in vacuum / Speed of light in flint glass
= (3.00 × 108) / (1.86 × 108)
= 1.61
Absolute refractive index of crown glass = Speed of light in vacuum / Speed of light in crown glass
= (3.00 × 108) / (1.97 × 108)
= 1.52
(b) Relative refractive index for light going from crown glass to flint glass is given by:
(Speed of light in crown glass) / (Speed of light in flint glass)
= (1.97 × 108) / (1.86 × 108)
= 1.059
APPEARS IN
RELATED QUESTIONS
Which of the following diagrams shows the ray of light refracted correctly?
Give three examples of materials that refract light rays. What happens to the speed of light rays when they enter these materials?
Light enters from air into diamond which has a refractive index of 2.42. Calculate the speed of light in diamond. The speed of light in air is 3.0 × 108 ms−1.
The following table gives the refractive indices of a few media:
| 1 | 2 | 3 | 4 | 5 | |
| Medium | Water | Crown glass | Rock salt | Ruby | Diamond |
| Refractive index | 1.33 | 1.52 | 1.54 | 1.71 | 2.42 |
Use this table to give an example of:
(i) a medium pair so that light speeds up when it goes from one of these medium to another.
(ii) a medium pair so that light slows down when it goes from one of these medium to another.
State the laws of refraction of light. Explain the term 'absolute refractive index of a medium' and write an expression to relate it with the speed of light in vacuum.
State the law of refraction of light that defines the refractive index of a medium with respect to the other. Express it mathematically. How is refractive index of any medium 'A' with respect to a medium 'B' related to the speed of propagation of light in two media A and B? State the name of this constant when one medium is vacuum or air.
The refractive indices of glass and water with respect to vacuum are 3/2 and 4/3 respectively. If the speed of light in glass is 2 × 108m/s, find the speed of light in (i) vacuum, (ii) water.
Name a liquid whose mass density is less than that of water but it is optically denser than water.
n = _______. This law is also called as Snell’s law.
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?
What happens when a light ray passes from a rarer medium to a denser medium?
