Distances measured in mirror problems must follow a definite rule
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
Distances measured in mirror problems must follow a definite rule. Answer the questions that follow with reference to this rule.
(i) State the sign convention used for measuring object distance u, image distance v and focal length f for spherical mirrors.
(ii) Using this convention, explain why the focal length of a concave mirror is negative while that of a convex mirror is positive.
(iii) A student calculates the magnification of a mirror to be m=−2. Explain what the negative sign of m tells about the nature and orientation of the image.