Question

An object is placed 30cm. Distance from the concave mirror image formed a distance of 60cm. Find the focal length of the mirror

Answer 1

here u go. hope it helps

Answer 2

Given:

Object distance(u) =30cm =30/100m =0.3m

Image distance(v) =60cm =60/100m =0.6m

Focal length(f) =?

Solution:

We have,

$1/f=1/u+1/v$

or, 1/f = 1/30/100 + 1/60/100

or, 1/f = 100/30 + 100/60

or, 1/f = 100 × 2 + 100/60

or, 1/f = 200+100/60

or, 1/f = 300/60

or, 1/f = 5

or, 5f = 1

f = 1/5

f = 0.2 m

Hence, the focal length of the mirror is 0.2m.