Question

An object of 4 cm long is placed at a distance of 20 cm in front of convex mirror having focal length 10 cm. Find the image distance and height.

Answer 1

The focal length(f) =10cm
object distance(u)=20cm
image distance(v)=?

1/f=1/u+1/v

1/10=1/(-20)+1/v

(1/10)+(1/20)=1/v

(2+1)/20=1/v

3/20=1/v

v=20/3

v=6.666=6.67

Image distance=6.67cm

we know

hi/ho=-v/u

hi/4=-6.67/20

hi=1.334

Image height =1.35cms