A tall object is placed in front of a convex mirror of focal length
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A 5cm tall object is placed 30cm in front of a convex mirror of focal length 10cm. A student knows the mirror formula but is unsure about the correct sign of focal length for the convex mirror.
(i) Using the correct sign for focal length, calculate the image distance v and the height of the image hi.
(ii) The same student repeats the calculation using f=−10cm instead of the correct sign. Determine the values of v′ and hi′ obtained in this incorrect attempt.
(iii) Briefly comment on how the wrong choice of sign changes the physical interpretation of the result, focusing on the position and nature of the image.