Refraction of light
Refraction of light
The change in direction of light when it passes from one medium to another obliquely is called refraction of light.
In other words the bending of light when it goes from one medium to another obliquely is called refraction of light.
The Refraction of light takes place when light rays enter from air into glass , or from glass into air. The refraction of light takes place when light enters from air into water, or from water into air. And the refraction of light also takes place when light enters from water into glass or from glass into water.
The optical instruments like camera, microscope and telescope work on the the refraction of light through glass lenses.
The refraction (or bending ) of light takes place at the boundary between the two media.
Causes of refraction-
The refraction of light is due to the change in the speed of light on going from one medium to another. Thus, when light goes from one medium to another, its speed changes. And this change in speed of light causes the refraction of light.
The refraction of light on going from air to glass takes place because the speed of light is different in air and glass: being more in air and lesser in glass. So when light enters from air into glass its speed changes. And this change in speed of light in in going from air to glass causes the refraction of light.
Greater the difference in the speed of light in the two media greater will be the amount of refraction of light.
Optically rarer medium-
A medium in which the speed of light is more is known as optically rarer medium ( or less dense medium)
Example- air is an optically rarer medium as compared to glass and water.
Optically denser medium-
A medium in which the speed of light is less is known as optically denser medium .
Example- Glass is an optically denser medium as compared to air and water.
** When a Ray of light goes from a rarer medium to a denser medium, it bends towards the normal (at the point of incidence).
**When a Ray of light goes from a denser medium to a rarer medium, it bends away from the normal ( at the point of of incidence).
Effects of refraction of light-
The refraction of light produces many effects which can be easily observed in our day to day life. For example-
(1) A stick or pencil held obliquely and partly immersed in water appears to be bent at the water surface.
(2) an object placed under water appears to be raised.
(3) a pool of water appears to be less deep than it actually is.
(4) when a thick glass slab is placed over some printed matter the letters appear raised when viewed from the top.
(5) A lemon kept in water in a glass tumbler appears to be bigger than its actual size when viewed from the sides.
(6) The stars appear to twinkle on a clear night.
(7) The sun appears upper side to its original position.
The change in direction of light when it passes from one medium to another obliquely is called refraction of light.
In other words the bending of light when it goes from one medium to another obliquely is called refraction of light.
The Refraction of light takes place when light rays enter from air into glass , or from glass into air. The refraction of light takes place when light enters from air into water, or from water into air. And the refraction of light also takes place when light enters from water into glass or from glass into water.
The optical instruments like camera, microscope and telescope work on the the refraction of light through glass lenses.
The refraction (or bending ) of light takes place at the boundary between the two media.
Causes of refraction-
The refraction of light is due to the change in the speed of light on going from one medium to another. Thus, when light goes from one medium to another, its speed changes. And this change in speed of light causes the refraction of light.
The refraction of light on going from air to glass takes place because the speed of light is different in air and glass: being more in air and lesser in glass. So when light enters from air into glass its speed changes. And this change in speed of light in in going from air to glass causes the refraction of light.
Greater the difference in the speed of light in the two media greater will be the amount of refraction of light.
Optically rarer medium-
A medium in which the speed of light is more is known as optically rarer medium ( or less dense medium)
Example- air is an optically rarer medium as compared to glass and water.
Optically denser medium-
A medium in which the speed of light is less is known as optically denser medium .
Example- Glass is an optically denser medium as compared to air and water.
** When a Ray of light goes from a rarer medium to a denser medium, it bends towards the normal (at the point of incidence).
**When a Ray of light goes from a denser medium to a rarer medium, it bends away from the normal ( at the point of of incidence).
Effects of refraction of light-
The refraction of light produces many effects which can be easily observed in our day to day life. For example-
(1) A stick or pencil held obliquely and partly immersed in water appears to be bent at the water surface.
(2) an object placed under water appears to be raised.
(3) a pool of water appears to be less deep than it actually is.
(4) when a thick glass slab is placed over some printed matter the letters appear raised when viewed from the top.
(5) A lemon kept in water in a glass tumbler appears to be bigger than its actual size when viewed from the sides.
(6) The stars appear to twinkle on a clear night.
(7) The sun appears upper side to its original position.
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