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

Options

A. `(lf)/(d-f)`
B. `(d-f)/(lf)`
C. `l(f^(2))/((d-f)^(2))`
D. `((d-f)^(2))/(f^(2))l`

Answer

C

Explanation

Use `(1)/(v)+(1)/(u)=(1)/(f)`
Find `v_(1)`, when u = d and `v_(2)`, when `u=d+l`
Size of image `=v_(1)-v_(2)=l((f)/(d-f))^(2)`