Question

fig- Q(5)
A parallel beam of rays is incident on a convergent lens with a focal length of
40cm. Where a divergent lens with a focal length of 15 cm should be placed for
the beam of rays to remain parallel after passing through the two lenses? Draw
a ray diagram. (AS)
inale​

Answer 1

Answer:

25

Explanation:

If an incident ray is approaching focus of a divergent lens then they become parallel to principal axis.

So if convergent and divergent lens focus coincide then the ray will become parallel to principal axis.

Hence x+15=40

x=25cm

Hence divergent lens should be 25 cm behind convergent lens.