A Cassegrain telescope has a primary mirror with a 5-m diameter and a hole with a diameter of 5 cm through the primary mirror.By what percentage is the light-gathering power of the mirror reduced because of the hole?
A) 0.01%
B) 1%
C) 20%
D) 50%

Question

Quizplus · Accepted Answer

The light-gathering power is proportional to the area of the mirror. The area of the hole is negligible compared to the area of the primary mirror, resulting in a reduction of approximately 0.01%.

A Cassegrain Telescope Has a Primary Mirror with a 5-M