Two converging lenses of unequal focal lengths can be used to reduce the aperture of a parallel beam of light without losing the energy of the light. This increase the intensity. Describe how the converging lenses should be placed to do this.

Question

Philoid · Accepted Answer

We know that, refraction through a convex lens, leads to a converging beam. So, placing the second convex kens within range of first one’s focus will make the aperture reduced and also won’t lose energy.