Question

A mirror produces an image of (+)15 cm height, when the object is placed 20 cm away from

the mirror. The object is only 10 cm in height. Calculate the focal length of the mirror.

Answer 1

HEYA GM ❤

★ magnification (m) = - V/U

h(image) / h ( object ) = - V/U

15 / 10 = -V/ -20

V ( image distance ) = 3/2 × 20 = 30cm

★ By, Mirror Formula ;

1/V + 1/U = 1/F

1/30 + 1/ (-20) = 1/F

2 - 3 / 60 = 1/F

F = - 60cm

A. Focal length = -60cm

TQ ❤ ❤