The amount of solar energy reaching a given unit of Earth's surface depends primarily on the
A) concentration of greenhouse gases.
B) strength of the winds.
C) amount of cloud cover.
D) moisture content of the air.
E) angle of the sun's rays.

Question

Quizplus · Accepted Answer

The angle of the sun's rays determines the amount of solar energy reaching a given unit of Earth's surface. If the rays are more directly overhead, the surface receives more energy per unit area. If the rays are at a lower angle, the energy is spread over a larger area and is less intense. The other factors listed may indirectly affect the amount of solar energy reaching the surface, but the angle of the sun's rays is the primary factor.

The Amount of Solar Energy Reaching a Given Unit of Earth's