If your pupil is 1 cm across,how large does a telescope aperture have to be to collect one million times more light than your eye?
A) 10 cm
B) 1 m
C) 10 m
D) 100 m

Question

Quizplus · Accepted Answer

The area of the pupil is pi*(1/2)^2 = pi/4 cm^2. The area of the telescope aperture must be 1 million times larger, or pi*(1000000/4) = 2500000pi cm^2. The radius of the telescope aperture must be sqrt(2500000pi/pi) = 1000 cm, or 10 m.

If Your Pupil Is 1 Cm Across,how Large Does a Telescope