A concave mirror of focal length 15 cm is cut into two pieces whose poles are at y=+3 cm and y=−3 cm, axes parallel. A point object is at y=+2 cm and 25 cm from the mirror plane. Find the vertical separation of the two images in centimetres.
Physics · Geometrical optics · spherical mirror
JEE Mains NEET

Question

A concave mirror of focal length 15 cm is cut into two pieces whose poles are at y=+3 cm and y=−3 cm, axes parallel. A point object is at y=+2 cm and 25 cm from the mirror plane. Find the vertical separation of the two images in centimetres.

Physics · Geometrical optics · spherical mirror

G1 Physics · Accepted Answer

For u=25, v=15×25/(25−15)=37.5 and m=−1.5. Upper piece: object height relative axis=−1, image relative height=+1.5, so y=4.5. Lower piece: relative object height=+5, image relative height=−7.5, so y=−10.5. Separation=15 cm.