A lens of focal length f is placed in between an object and screen at a distance D. The lens forms two real images of object on the screen for two of its differenct positions, a distance x apart. The two real images have magnifications `m_(1)` and `m_(2)`, respectivelly `(m_(1)gtm_(2))`. Then,

Options

A. `f=x//(m_(1)-m_(2))`
B. `m_(1)m_(2)=1`
C. `f=(D^(2)-x^(2))//4D`
D. `Dge4f`.

Answer

a.,b.,c.,d.

Explanation

`v+u=D`
and `v-u=xrArr v=(D+x)/(2),u=(D-x)/(2)`, and `f=(D^(2)-x^(2))/(4D)`
`m_(1)=(D+x)/(D-x),m_(2)=(D-x)/(D-x)`