Advertisements
Advertisements
प्रश्न
Define the term refractive index of a medium. What do you understand by the statement 'the refractive index of glass is 1.5 for white light'?
Advertisements
उत्तर
When light travels from one medium (air) to another medium (glass), it bends towards the normal. The extent of bending of light depends upon the speed of light (v2) in the second medium, compared to the speed of light (v1) in the first medium. The refractive index of the second medium w.r.t. the first medium (n21) is given by
n21 = Speed of light (v1) in first medium / speed of light (v2) in second medium
The refractive index of glass is typically around 1.5, meaning that light in glass travels at
c / 1.5 = 200,000 km/s. A low value of refractive index also indicates a large critical angle at the glass-air interface.
APPEARS IN
संबंधित प्रश्न
Define refraction and state the laws of refraction.
A ray of light passes from water to air. How does the speed of light change?
How is the angle of emergence related to the angle of incidence when prism is in the position of minimum deviation? Illustrate your answer with help of a labelled diagram using an equilateral prism?
A total reflecting right angled isosceles prism can be used to deviate a ray of light through:
(a) 30° (b) 60° (c) 75° (d) 90°.
A student traces the path of a ray of white light through a rectangular glass slab and marks, the angles of incidence (∠i) , refraction (∠r) and emergence (∠e) as shown. Which angle or angles has he not marked correctly?
(A) ∠i only
(B) ∠i and ∠r
(C) ∠i and ∠e
(D) ∠r and ∠e
Write a relation between the angle of incidence (i), angle of emergence (e), angle of the prism (A), and angle of deviation (d) for a ray of light passing through an equilateral prism.
Define the term refractive index of a medium in terms of velocity of light.
Complete the ray diagram showing its emergence into the air after passing through the prism.
The speed of light in air is 3 × 108 ms-1. Calculate the speed of light in water. The refractive index of water is 4/3.
