A candle is placed 15 cm from the vertex of a concave mirror that has a focal length of 10 cm.

A candle is placed 15 cm from the vertex of a concave mirror that has a focal length of 10 cm. Find the magnification of the image.

M = –ID/OD = –15/OD

1/OD + 1/ID = 1/FL

1/OD + 1/15 = 1/10

1/OD = –1/15 + 1/10

M = –15(1/OD) = –15(–1/15 + 1/10)

M = 1 – 15/10 = –0.5

The image will be in front of the mirror, inverted, and half the size of the candle.