Figure given below shows a beam of light converging at point P. When a concave lens of focal length 16cm is introduced in the path of the beam at a place O shown by dotted line such that OP becomes the axis of the lens, the beam converges at a distance x from the lens. The value x will be equal to

48/7 cm

From the figure shown it is clear that

For lens: u = 12 cm and v = x = ?

By using $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$ we have $\frac{1}{+16}=\frac{1}{x}-\frac{1}{+12}$

⇒ x = 48/7 cm.