Question

A convex mirror forms the image of an object placed at a distance 40 cm in front of mirror, at distance 10 cm. Find the focal length of mirror.

Answer 1

Explanation:

given: u = 40 CM ( negative)

v = 10 ( positive)

f = ?

since the image formed by a convex mirror is always virtual, erect and on other side of mirror.

from relation 1 / u + 1/v = 1/ f,

1/-40 + + 1/10 = 1/ f

1/ f= -1+4/ 40

1/ f = 3/ 40

f= 40/ 3 = 13•33