Question

An object is placed at a distance of 50 m from convex mirror a plane mirror if placed in front of the convex mirrors in such a way that it covers half of the convex mirror if distance betwwen object and plane mirror is 30cm

Answer 1

Here the plane mirror and the convex mirror both form the image at the same position.

Object distance from the plane mirror=30 cm

So, Image distance =30 cm (Behind the mirror)

Thus formed image is at a distance of 10 cm behind the convex mirror.

Now,

For convex mirror,

u=-50 cm

v=10 cm

Using mirror formula,

1/v +1/u=1/f

1/10 -1/50=1/f

or f=12.5 cm

So R=2f=25 cm