Sunday 13 October 2013

Types of spherical mirror and their points.

Figure 1.1
Figure 1.2

Here we will study about the types of Spherical mirror. We know that Spherical mirror have two types:

  1. Concave mirror
  2. Convex mirror
Concave mirror:

                                Concave mirror is a spherical mirror whose inner curved surface reflecting. In concave mirror the size of image depends on the position of the object. Both virtual and real image can be formed by concave mirror.

Convex mirror:

                               Convex mirror is a spherical mirror whose outer curved surface is reflecting. In convex mirror the size of the image is always smaller than the object. Only virtual and erect image is formed by a convex mirror.

Another points of mirror are present below:

 Pole:

            It is the midpoint of the curved surface of spherical mirror. It is also called vertex.

Centre of Curvature:

                                        A spherical mirror is a part of sphere. the centre of this sphere is known as Centre of Curvature.

Radius of Curvature:

                                          It is the radius of the sphere from centre of curvature to spherical mirror.

Principal Axis:

                               It is the line which join centre of curvature to the pole of spherical mirror.

The Principal Focus:

                                          The principal focus of concave and convex mirror is different. In concave mirrror, After reflection from  a mirror, rays parallel to the principal axis converge to a Point F. This point if Principal Focus of concave mirror . Principal focus of concave mirror is also known as real focus. Int he case of convex mirror, rays parallel to the principal axis after reflection appear to come from a point F situated behind the mirror. This point is called the Principal focus of convex mirror. The principal Focus of the convex mirror is also known as virtual focus.

Focal Length:

                            It is the distance from the pole to the principal focus measured along the principal axis.

These all points you see in the above figure.



 

                              

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