An object `2 cm` high is placed at a distance of `16 cm` from a concave mirror, which produces a real image `3 cm` high. What is the focal length of the mirror ? Find the position of the image ?

Options

A. `-9.6 cm`
B. `-3.6 cm`
C. `-6.3 cm`
D. `-8.3 cm`

Answer

A

Explanation

Here, ` h_(1) = 2 cm, u = -16 cm`
`h_(2) = - 3cm` (since image is real and inverted)
` :' m = (h_(2))/(h_(1)) = - (v)/(u) :. V = (-h)/(h_(1)) u = 3/2 xx (-16) = - 24 cm`
` (1)/(f) = 1/v + 1/u = = - 1/24 - 1/16 = (-2-3)/(48) = (-5)/(48), f = (-48)/(5) = - 9.6 cm`