Some important terms in geometrical optics

 

Some important terms in geometrical optics

Reflection of light: When the light rays strike the barrier and most of the rays return to the same medium is called reflection of light. There are different terms that are used to describe the reflection of light.

Incident ray: The coming ray which strikes the barrier is called the incident ray.

Reflected ray: The return back of the ray after the strike is called the reflected ray.

Point of incident: The point where the incident ray strikes the barrier is called the point of incident.

Normal: The imaginary line drawn between the incident and the reflected ray is called normal.

The angle of incident: The angle incident ray makes the barrier is called the angle of incident. It is represented by θ_i .

Angle of reflection: The angle which makes between the reflected ray and the normal is called the angle of the reflected ray. It is represented by θ_r.

Laws of reflection: it is the relation between the incident, reflected ray, and normal line. The laws of reflection is describe two statements which given below one by one.

First law of reflection: This law explain the incident ray, the reflected ray and the normal all three are be the same plane.

Second law of reflection: According to this statement of the law the incident angle is equal to the reflected ray. Mathematically

                                            Θ_i = θ_r

Image characteristics: Any image has four characteristics, for completely describe the image we must describe these four characteristics which are given below one by one.

a)     Magnification: The ratio between the image size and object size is called magnification.

 M>1

Then the image will be greater than the object.

M=1

When the magnification is equal to the one its means that the object and the image will be the same size.

 M<1

 Which means that the image will be smaller than the object.

b)    Attitude: This shows the orientation of the image which means that I.e

Left side, right side, upward or downward with respect to the object.

c)     Location or position: The distance between the image and the object is

called the location or position of an object.

Focal point of a concave mirror: The incident light is perpendicular strikes the mirror and the ray is parallel to the strikes the mirror and reflected back and strikes the point and this point is known as the focal point. The relation between the focal point and the radius of the mirror is given below:

                                                F=

The focal point of the concave mirror is always real.

Focal point and focal length of the convex mirror: When the light rays skrike the convex mirror reflects back the same medium so we extend the ray and where its meets the main axis, it is known as the focal point of the convex mirror.

The mirror equation: The mirror equation is the mathematical relationship between the object distance and image distance for a given mirror.

                                                

Magnification: The magnification of the mirror tells us about the details about the

Object higher the magnification more the detail.