The intensity of a wave at a certain point is I. A second wave has twice the energy density and 3 times the speed of the first. What is the intensity of the second wave?
A) I
B) 2I
C) 3I
D) 6I
E) 2I/3

Question

Quizplus · Accepted Answer

Intensity is proportional to the energy density and the square of the speed of a wave. Thus, the intensity of the second wave is (2 times the energy density) x (3 times the speed)^2 = 18I. Therefore, the answer is D) 6I.

The Intensity of a Wave at a Certain Point Is