A convergent beam of light passes through a diverging lens of focal length `0.2 m` and comes to focus at a distance of `0.3 m` behind the lens. Find the position of the point at which the beam would converge in the absence of the lens.

Options

A. `0.12 m`
B. `0.6 m`
C. `0.3 m`
D. `0.15 m`

Answer

A

Explanation

Here `f = -0.2 m, v = +0.3 m`
The lens formula
`1/v - 1/u = 1/f rArr 1/u = 1/v - 1/f = (1)/(0.3) + (1)/(0.2) = (0.5)/(0.06)`
`u = (0.06)/(0.5) = 0.12 m`