question_answer

Figure given below shows a beam of light converging at point P.  When a convex lens of focal length 16 cm 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                                  [AMU (Med.) 2002]

A)            12 cm

B)            24 cm

C)            36 cm

D)            48 cm

Correct Answer: D

Solution :

                   By using lens formula                    \[\frac{1}{-16}=\frac{1}{v}-\frac{1}{(+12)}\Rightarrow \frac{1}{v}=\frac{1}{12}-\frac{1}{16}=\frac{4-3}{48}\]\[\Rightarrow \]\[v=48\]\[cm\]