Question

A convax and a concave mirror each of radius `10 cm` are placed facing eachother at `15 cm` distance. A point object is placed midway between them. Find the position of the final image if reflection takes place first at the concave mirror and then convex mirror.

Answer 1

As shown in Fig.

`P_(1)P_(2) = 15 cm`
`OP_(1) = u = - 7.5 cm`
`R = - 10cm`, for concave mirror As `(1)/(v) + (1)/(u) = (1)/(f) = (2)/(R )`
`(1)/(v) = (2)/(R ) - (1)/(u) = (2)/(-10) - (1)/(-7.5) = (-1)/(5) + (2)/(15)`
`(1)/(v) = (-1)/(15)`
`:. v = - 15 cm`, which is `P_(1)I`
Thus image `I` of object `O` is formed by concave mirror at the pole `P_(2)` of convex mirror. Hence final image is formed at the pole of convex mirror, just behind `P_(2)`.