Which of these statements best explains why the size of the refracting telescope lens is kept small at the cost of reducing its capacity to gather radiations from space?

•big telescopes are more portable.
•big lenses gather harmful radiations from space.
•big lenses do not focus light properly to produce clear images.
•big telescopes are not reliable enough to be used for research.

Answer : Big lenses do not focus light properly to produce clear images.

Explanation :

A telescope that uses a combination of mirrors which is used to reflect light and forms an image.

The first reflecting telescope was invented by Newton in 1668. The size of the refracting telescope lens is kept small at the cost of reducing its capacity to gather radiations from space.

The correct option is (c) " Big lenses do not focus light properly to produce clear images ".