Terms about sperical mirror
Answers
Explanation:
CENTRE OF CURVATURE (C)
The centre of curvature of a spherical mirror is the centre of the imaginary hollow sphere of glass, of which the spherical mirror is a part. The centre of curvature is usually denoted by the letter C. The centre of curvature of a concave mirror is in front of it and the centre of curvature of convex mirror is behind it as shown in the figure 1.
RADIUS OF CURVATURE (R)
The radius of curvature of a spherical mirror is the radius of the imaginary hollow sphere of glass, of which the spherical mirror is a part. The radius of curvature is usually denoted by the letter ‘R’.
In figure 1 (a) the distance PC is the radius of curvature of a concave mirror and in figure (b) the distance PC is the radius of curvature of a convex mirror.
POLE (P)
The centre of the reflecting surface of a spherical mirror is called its pole. It is usually denoted by the letter ‘P’ in each concave and convex mirror. The pole of a spherical mirror lies on the surface of the mirror as shown in figure 1 (a, b).
PRINCIPAL AXIS
The principal axis of a spherical mirror is the straight line passing through the centre of curvature C and pole P of a spherical mirror, produced on both sides.
In the figure 1 (a, b) x x¢ is the principal axis of a concave and convex mirror.
APERTURE
The portion of a mirror from which the reflection of light actually takes place is called the aperture of the mirror. It is also called linear aperture of the mirror. The aperture of a spherical mirror is denoted by the diameter of its reflecting surface. In the figure 1 (a, b) MN represent the aperture of concave and convex mirror.
Note: In fact the aperture of a mirror represents the size of the mirror.
