Question

At what distance should an object be placed from a lens of focal length 25 cm to obtain an image on a screen placed at a distance of `50 cm` from the lens ? What will be the magnification produced in this case?

Answer 1

Here, `u=?, f=25 cm, v=50cm, m=?`
From `(1)/(v) - 1/u = (1)/(f), - 1/u = (1)/(f) - (1)/(v) = 1/25 - 1/50 = 1/50`
`u = -50cm`.
And `m = v/u = 50/-50 = -1`
Negative sign of m indicates that image would be inverted.