An object is placed in front of a concave mirror of radius of curvature `40 cm` at a distance of `10 cm`. Find the position, nature and magnification of the image.

Answer

`20 cm`, virtual, erect behind the mirror, `m = + 2`

Explanation

Here, `R = -40 cm, u = -10 cm, v = ?`
From the mirror formula
`(1)/(v)+(1)/(u)=(2)/( R)`
`(1)/(v)=(2)/( R)-(1)/(u) = (2)/(-40)-(1)/(-10) = (1)/(20)`
`v = 20 cm`
As `v` is positive, image is virtual, erect and formed behind the mirror Magnification,
`m = (-v)/(u) = (-20)/(-10) = 2`.