12-04-2014, 12:16 PM
LIGHT : REFLECTION AND REFRACTION
REFLECTION AND REFRACTION.ppt (Size: 1.27 MB / Downloads: 405)
Light :-
i) Light is a form of energy which helps us to see objects.
ii) When light falls on objects, it reflects the light and when the
reflected light reaches our eyes then we see the objects.
iii) Light travels in straight line.
iv) The common phenomena of light are formation of shadows,
formation of images by mirrors and lenses, bending of light by a
medium, twinkling of stars, formation of rainbow etc.
Spherical mirrors
Spherical mirror is a curved mirror which is a part of a hollow sphere. Spherical mirrors are of two types. They are concave mirror and convex mirror.
i) Concave mirror :- is a spherical mirror whose reflecting surface is curved inwards. Rays of light parallel to the principal axis after reflection from a concave mirror meet at a point (converge) on the principal axis.
ii) Convex mirror :- is a spherical mirror whose reflecting surface is curved inwards. Rays of light parallel to the principal axis after reflection from a convex mirror get diverged and appear to come from a point behind the mirror.
Refraction of light :-
When light travels obliquely from one transparent medium into another it gets bent. This bending of light is called refraction of light.
When light travels from a rarer medium to a denser medium, it bends towards the normal.
When light travels from a denser medium to a rarer medium to a rarer medium, it bends away from the normal.