Question

1. Draw a diagram to show how a converging lens focusses parallel rays of light.
2. How would you alter the above diagram to show how a converging lens can produce a beam of parallel rays of light.

Answer 1

a. When rays of light from a distant object pass through a converging lens, the light rays converge at the focus of the lens (fig.). 

 

b. When rays of light come from the focus of the lens, the emergent rays of light are parallel to the principal axis.