Edited by Sim, Jen Moreau
Definitions of Special terms
- 2Pole:The geometric center of a spherical mirror is called pole or vertex. It is denoted by 'P'.
- 3Aperture:is the distance between the extreme points (MM') of the mirror OR The diameter of the mirror.
- 4Principal Axis:The straight line passing through the pole 'P' and the center of curvature 'C' is called the principal axis. AB is the principal axis in the fig.
- 5Concave mirrors:converge to a point, called the principal focus, that is denoted by 'F'.
- 6Focal Length:The distance between pole 'P' and the principal focus 'F' is called focal length. It is denoted by 'f'. It is equal to half the radius of curvature. f = r/2 The focal length of a concave mirror is considered as positive.
Rules for Obtaining Images Formed by a Concave Mirror
When an object is placed in front of a concave mirror, an image is formed. The point of intersection of any of the two rays shows the image point "I" of object "O". The rays which are reflected from a concave mirror follow certain rules as under.
- 1A ray coming parallel to the principal axis is reflected through the principal focus of the concave mirror.
IMAGE FORMATION BY CONCAVE MIRROR
The type of images formed by a concave mirror depends on the position of the object to the mirror. If the distance of an object say OO' from a concave mirror is changed, then the nature, size, and location of the image are also changed.
Formation of different images depending on the position of the object are shown below:.
- 5Fifth Position:(between 'F' and 'P'). When the object is placed between the pole and principal focus, then virtual, erect and larger image will be formed.Advertisement
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Concave Mirrors. (2017). In ScienceAid. Retrieved Mar 25, 2017, from https://scienceaid.net/Concave_Mirrors
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Categories : Physics
Recent edits by: Sim