Two halves of a concave mirror of focal length 30 cm are rotated by +1° and −1°. For a distant axial object, find the approximate separation of the two images in centimetres using tan2°≈0.0349.
Physics · Geometrical optics · spherical mirror
JEE Mains NEET

Question

Two halves of a concave mirror of focal length 30 cm are rotated by +1° and −1°. For a distant axial object, find the approximate separation of the two images in centimetres using tan2°≈0.0349.

G1 Physics · Accepted Answer

Each reflected chief ray is rotated by ±2°, so each image is displaced by f tan2°≈30×0.0349=1.047 cm from the original focus. Total separation≈2.094 cm.