What is the ratio of the light energy that falls on a unit area of Mercury's surface compared to that falling on a unit area of Earth's Moon if Mercury is at 0.4 AU and the Moon is at 1.0 AU from the Sun?
A) 1
B) 6.25
C) 2.5
D) 16

Question

Quizplus · Accepted Answer

The light intensity is inversely proportional to the square of the distance from the source. So, the ratio of the light energy falling on Mercury to that falling on the Moon is (1/0.4)^2 / (1/1)^2 = 6.25.

What Is the Ratio of the Light Energy That Falls