Suppose your telescope has perfect mirrors and is limited only by diffraction.If you are viewing with light of 400 nm wavelength,what diameter mirror in a space telescope would have 1.0-km resolution of objects on Mars when viewed from above the earth at a time when the Earth-Mars distance of 80 million kilometers?
A)39 km
B)3.9 m
C)3.9 km
D)39 m
E)390 m

Question

Quizplus · Accepted Answer

The diffraction limit formula is θ = 1.22 * (λ/D), where θ is the angular resolution, λ is the wavelength, and D is the diameter of the telescope. Solving for D with θ = 1 km / 80,000,000 km and λ = 400 nm gives approximately 39 meters.

Suppose Your Telescope Has Perfect Mirrors and Is Limited Only