Advertisements
Advertisements
Question
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
Advertisements
Solution
Refractive index of a medium nm is given by,
`n_m="Speed of light in vacuum"/"Speed of light in the medium" = c/v`
Speed of light in vacuum, c = 3 × 108 m s−1
Refractive index of glass, ng = 1.50
Speed of light in the glass,
`v = c/n_g`
`= (3 xx 10^8)/1.50`
`= 2 xx 10^8ms^(-1)`
APPEARS IN
RELATED QUESTIONS
What is lateral inversion? Explain by giving a suitable example.
What type of reflection of light takes place from a cinema screen?
An extended object in the form of an arrow pointing upward has been placed in front of a plane mirror. Draw a labelled ray-diagram to show the formation of its image.
The image formed by a plane mirror is :
(a) virtual, behind the mirror and enlarged.
(b) virtual, behind the mirror and of the same size as the object.
(c) real, at the surface of the mirror and enlarged.
(d) real, behind the mirror and of the same size as the object.
A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is ______.
Explain how to read the following message which was found on some blotting paper:
Which phenomenon of light makes the water to appear shallower than it really is?
When a light ray passes from air into glass, what happens to its speed? Draw a diagram to show which way the ray of light bends.
The depth of a pond when seen from above appears to be less.
Image is formed by a mirror due to refraction of light.
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
A light ray suffers reflection and refraction at the boundary in passing from air to water. Draw a neat labelled ray diagram to show it.
The size of image of an object by a convex lens of focal length 20 cm is observed to be reduced to `1/3` rd of its size . Find the distance of the object from the optical centre of the lens .
Write scientific reason.
A pencil appears to be broken near the surface of water.
Why does a ray of light bend when it travels from one medium to another?
The phenomenon of light passing through the object is called ______.
Light bends as it passes from one medium to another. What is this phenomenon called?
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
Which is optically denser out of the two medium M1& M2 having the refractive indices = 1.71 and 1.36 respectively?
A ray of light starting from diamond is incident on the interface separating diamond and water. Draw a labelled ray diagram to show. the refraction of light in this case.
