A concave mirror gives magnifications −2 and −3 for two real-object positions separated by 15 cm. Find |f| in centimetres.
Physics · Geometrical optics · spherical mirror
JEE Mains NEET

Question

A concave mirror gives magnifications −2 and −3 for two real-object positions separated by 15 cm. Find |f| in centimetres.

G1 Physics · Accepted Answer

u₂−u₃=f[(1+1/2)−(1+1/3)]=f/6=15, so f=90 cm.