Page 134 - Innovator's Science-8

Regular And Diffuse Reflection

Although, light falls on and is reflected by all kinds of surfaces, we can only
see the images of objects from polished surfaces like mirrors.

To know more about reflection, let us first learn about beams of light. A
group of light rays coming from the same sources in the same direction is
called a beam of light . There are three types of beams of light:

i. Parallel beam of light: Beat Beams of light that are parallel to each other.
ii. Convergent beam of light: Beams of light which actually meet

(coverage) or appear to meet at a point.
iii. Divergent beam of light: Beams of light which actually spread or appear

to spread (diverge) from a point.

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Testimony a. Parallel beams b. Convergent beams c. Divergent beams
Every surface around us Beams of Light
reflects light - but not all
reflec ons are alike! When a parallel beam of light falls on a polished surface, it is reflected back
When light strikes a in one direction. Whereas when a parallel beam of light falls on a rough
smooth surface like a
mirror or calm water, the surface, it is reflected back in many directions.
rays bounce off evenly, On the basis of reflecting surface, we can categorise reflection into two types:
producing a clear image.
This is called regular i. Regular reflection (Fig. a)
reflec on. But when the
same light hits a rough • It is also called specular reflection.
surface such as paper, • It is the reflection from polished surfaces.
walls, or unpolished Parallel Parallel
wood, the rays sca er in • Reflected rays are parallel to each other. incident reflected
many direc ons. This • The image is seen in the reflecting surface. rays rays
diffuse reflec on helps us
see most everyday • It can be seen in a plane mirror, unused Polished surface
objects, even though they stainless steel plate, water, etc. a. Regular reflection
do not form images like
mirrors do! ii. Diffuse reflection (Fig. b)
Unparallel
• It is also called irregular reflection. reflected
rays
• It is the reflection from rough or irregular
Parallel
surfaces. incident
rays
• Reflected rays move in various directions.
• The image is diffused or irregular.
Rough surface
• It can be seen in scratched mirrors, b. Diffuse reflection
rippling water, etc. Type os reflection

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