Sign Convection For Spherical Mirror and Important Terms with regard to Spherical Mirrors

Important Terms with regard to Spherical Mirrors

Aperture- The diameter of the part of mirror which is is exposed to the incident light is called aperture.

Principle Axis- The line which joins the Center of curvature and the pole of a spherical mirror

Principle focus- A point on principle axis where all the parallel incident rays meet or appear to meet is called principal axis

Principal focus for a concave mirror is real as incase of concave mirror parrallel rays after reflection really meet on point where principal focus is obtained but, for convex mirror the focus is not real i.e it is virtual as reflected rays, appear to meet after reflection behind the mirror.

Focal Plane- The plane which is perpendicular to the principal axis and passes through the principal focus is called its focal plane.

Focal Length- The distance between pole(P) and principal focus(F) is called or known as focal length of that spherical mirror.

Sign Convection For Spherical Mirror

Object is always placed on the left side of spherical mirror.

All the distances are measured from pole of the spherical mirror.

Distance in the same direction of incident ray are positive and while distance opposite to the direction of incident ray are always negative.

Distances upward along with perpendicular to the principal axis are always taken as positive and distances downward along with perpensicular to principal axis are always negative.

Focal length(f) = R/2 ,
i.e focal length of spherical mirror = half of radius of curvature of that spherical mirror.

Radius of plane mirror is infinite. focal length of plane mirror is infinite