Question

An object is placed exactly midway between a convex and a concave mirror each of focal length 15 cm. The two mirrors are placed 60 cm apart and the two mirrors face each other. Find the nature and position of the image formed by reflection first at convex and then at the concave mirror.

Answer 1

For the convex mirror,

u=-30cm,f=15cm

Using,

1/f=1/u+1/v

1/15=-1/30+1/v

v=10cm

Therefore the image is at 10 cm behind the convex mirror and virtual.

Now for concave mirror his image will act as an object,so u=-(60+10)=-70cm,f=-15cm

then,

-1/15=-1/70+1/v

v=-19.09cm ie real,inverted image at a distance of 19.09cm.