Page 162 - Science Class 08
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Light : Its Refraction
• Refrac on of Light • Laws of Refrac on
• Refrac ve Index • Denser and Rare Medium
• Refrac on Through a Glass Slab • Refrac on Through a Prism
• Dispersion of Light • Op cal Illusion
We have read about light in our previous classes REFRACTION OF LIGHT
and we know certain basic facts about it. We know that light-rays travel in straight lines
v Light travels in a straight line. in the air which is a transparent medium just as
v When light strikes a surface, a part of it water and glass are. So, let us try to follow
gets sca ered, a part may be transmi ed what happens when a beam of light travelling
and the rest of it gets absorbed. in the air falls on the surface of water.
v When light falls on a mirror, it is reflected Focal Point
according to certain laws.
v Light causes the mirror to form images of
various sizes and natures.
F
v The materials that allow most of the light
falling on it to pass through them are said
to be transparent.
When a ray of light passes from the air into
v Glass, water, air and certain plas cs are
glass, it deflects from its straight path. This
common examples of transparent materials.
deflec on is called refrac on. The degree of
Now, we shall study more facts about light.
refrac on depends on the type of material in
We shall try to follow: which the ray enters. Different types of
v What happens when light enters from one materials reflect light to different degrees.
transparent medium into another? Diamond reflects light much more than glass or
v What is white light made up of? plas cs.
162 Science-8
