Understand basic concept of light and properties

light and their types

2. Light
Whatmakesthingsvisible:-
Lighthelpsustoseeobjects.
Wecannotseeobjectsinthedark.
Anobjectbecomesvisiblewhenlightemittedor
reflectedbyitreachesoureyes.

3. 2) Reflection of light :-When light falls on a polished or shiny surface it changes its direction. This
is called reflection of light..

4. Incident Ray -
The light ray, which strikes any surface, is called the incident ray.
Reflected Ray -
The ray that comes back from the surface after reflection is known as the
reflected ray
Normal
-The perpendicular line drawn at the point of incidence is called normal.
Angle of Incidence
The angle between the normal and
incident ray is called angle of incidence (∠i).
Angle of Reflection
The angle between the normal and
reflected ray is called angle of reflection (∠r).
The angle of incidence is always equal to the angle of reflection

5. Laws of reflection of light -
1)Angle of incidence is always equal to the angle of reflection.
2) The incident ray, the normal at the point of incidence and the reflected ray all lie in the same
plane.

6. Image formed by a plane mirror
i)The image is vertical
ii)The image is same size as the object
iii)The image is at the same distance from the
mirror as the object is in front of it.
i)The image is virtual (cannot be obtained
on a screen).
i)The image is laterally inverted.

7. Regular and Diffused Reflection
Regular Reflection
Reflection from a smooth surface like a mirror that follows the laws of reflection is called a
regular reflection
When parallel rays of light fall on a smooth surface, the reflected rays are parallel. This is
called regular reflection.
Regular reflection forms images of objects.

8. Diffused Reflection
Reflection over a surface that has irregularities where it does not follow the laws of reflection
is called an irregular or diffused reflection.
When parallel rays of light fall on a rough surface, the reflected rays are not parallel. This is
called diffused or irregular reflection.
Diffused reflection does not form images of objects.

9. Multiple images :-
When two mirrors are kept inclined at an angle, they can together form multiple images. This
is because the image formed by one mirror forms the object for the other mirror.

10. Kaleidoscope :-
A kaleidoscope is a device used to see multiple images of objects.
It has three inclined mirrors at an angle of 60°to each other.
This arrangement is usually kept in a cylindrical box and has a few pieces of coloured glasses
kept at one end .
We can see beautiful patterns and
designs due to multiple images formed by
the mirrors.

11. Dispersion of light :-
Sunlight or white light is a mixture of seven colors. The splitting up of sunlight or white light
into its colors is called dispersion of light .
When a beam of sunlight is passed through a glass prism it is split up into the seven rainbow
colors. The colours are violet, indigo, blue, green, yellow, orange and red (VIBGYOR)
Rainbow is caused due to the dispersion of sunlight by water drops in the atmosphere.by
the mirrors.