The intensity of the waves from a point source at a distance d from the source is I.What is the intensity at a distance 2d from the source?
A)4I
B)2I
C)I/2
D)I/4
E)I/

Question

The intensity of the waves from a point source at a distance d from the source is I.What is the intensity at a distance 2d from the source?
A)4I 
B)2I 
C)I/2 
D)I/4 
E)I/

Quizplus · Accepted Answer

According to the inverse-square law, the intensity of the waves from a point source is inversely proportional to the square of the distance from the source. Therefore, the intensity at a distance 2d is:
I/((2d/d)^2) = I/(4)
Hence, the intensity at a distance 2d is 1/4 of the intensity at a distance d. Therefore, the answer is D) I/4.

The Intensity of the Waves from a Point Source at a Distance