The intensity of sunlight per square meter reaching Jupiter is approximately what fraction of that at Earth's orbital distance? (For orbital radii,see Appendix,Table C-1,Comins,Discovering the Essential Universe,6th ed.)
A) 25 times
B) about the same
C) 1/5
D) 1/25

Question

Quizplus · Accepted Answer

The intensity of sunlight follows an inverse square law, which means that it decreases with the square of the distance. Jupiter's average distance from the Sun is about 5.2 astronomical units (AU), while Earth's distance is 1 AU. Therefore, the fraction of the intensity of sunlight at Jupiter compared to Earth would be (1/5.2)^2 or approximately 1/25. Therefore, the answer is D.

The Intensity of Sunlight Per Square Meter Reaching Jupiter Is