Question

A person stand straight in front of a convex mirror at a distance of 30m away from it .He sees his erect image whose height is 1÷6th real height .Find focal length of the convex mirror

Answer 1

Height of image/height of object=-v/u

1/6=-v/30

V=-5

As it is a convex mirror ,due to sign convention v=5 &u=-30

1/v+1/u=1/f

1/5+1/-30=1/f

1/f=30-5/150

f=150/25

f=6m