A short linear object of length b lies along the axis of a concave mirror of focal length f at a distanee u from the pole of the mirror. The size of the image is approximately equal to

Options

A. `b((u-f)/(f))^((1)/(2))`
B. `b((f)/(u-f))`
C. `b((u-f)/(f))`
D. `b((f)/(u-f))^2`

Answer

D

Explanation

`m_L=-(dv)/(du)=-((v)/(u))^2=-((f)/(u-f))^2` ltbr. Du: object length `dv:` image length
`(dv)/(b)=[(-f)/(-u-(-f))]^2`
Image length `=b((f)/(u-f))^2`