# Introduction Of Light

## Introduction of light

It is an agent which produces in us the sensation of sight. It itself is invisible but makes the other objects visible. It may be defined as the radiant energy which produces the sensation of light.

### Ray of Light

For better understand introduction of light we need to know about the ray of light.

It is a straight line path along which the transfer of light energy takes place.

#### Pencil of light rays

It is a group of inclined rays of light diverging from a point source or covering to another point.

### Beam Of light

As shown in the figure the group of parallel rays is called beam of light.

#### Divergent Rays

If rays of light are diverging from a point source so that, distance between  rays goes on increasing as they move forward, then the group is called divergent rays as shown in fig.

#### Convergent Rays

If rays of light are converting to a point so that, the distance between the rays goes on decreasing as they move forward, then the group is called convergent rays as shown in fig.

#### Parallel Rays

If successive light rays keep equal distance through, then they are parallel rays
In introduction of light these are different types of rays.

### Image.

If pencil of diverging from a point O is caused by reflection (or refraction)  to coverage or to appear to diverge from some other point I, then I is called image of the object O.

### Real Image

If reflected (or refracted) rays from first point appear to meet at the second point, then the second point is called real image of first point. Real image can be taken on the screen.

#### Virtual Image

If reflected (or refracted) rays from first point appear to meet at the second point, then it is called virtual image of first point. It cannot be taken on the screen.

### Reflection of Light

In introduction of light these are also important point that is reflection of light which means that how to reelect light.
It is bending of light to the first medium from the surface of separation of the two media. The rays are sent back by this process. The phenomenon of reflection of light is shown in figer.
Thus, the process of sending back the light rays which fall on the surface of an object is called reflection of light.it is basic introduction of light.

### Incident Ray

The ray of light originating from the source and falling on the surface of mirror shwoing the incident ray.

### Point of Incidence

It is the point at which the incident ray comes in contact with the mirror.  mid point is the incident point.

#### Reflected Ray

The ray of light which is sent back by the mirror is called reflected ray.

The normal is a line at right angles to the mirror surface at the point of incidence. NO is the normal.

#### Angle of Incidence

It is the angle made by the incident ray with the normal at the point of incidence.

#### Angle of Reflection

It is the angle made by the reflected ray with the normal at the point of incidence.

#### Regular Reflection

When a beam of parallel light rays falls on a shining but plane surface, the light rays are reflected back in the same order. It is regular reflection.

#### Irregular Reflection

When light beam falls on rough but uneven surface the light rays reflected back in many directions. This is known as irregular reflection. It gives scattered or diffused light.
Hence it is the introduction of light if you will find any incorrect above article you must comment below in comment box.
For Knowing more about the introduction of light you must watch this video.