AnswerThis Ch5

"Answer This" Questions

Chapter 5

5-A. I ntensity versus distance

Suppose you hear a firecracker go off 60 feet away from you. The intensity you hear is 0.09 Watts/m². What intensity would a person who is standing 20 feet away hear?
a) 0.81 Watts/m²
b) 0.27 Watts/m²
c) 0.09 Watts/m²
d) 0.03 Watts/m²
e) 0.01 Watts/m²

Answer:

The intensity changes as the square of the distance. Thus, if the distance is three times closer, as it is here (60/20 = 3), the intensity is 3² = 9 times as much. Since 0.09x9=0.81 W/m², the answer is a).

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	Back to "Answer-This" Listing "Answer This" Questions Chapter 5 5-A. I ntensity versus distance Suppose you hear a firecracker go off 60 feet away from you. The intensity you hear is 0.09 Watts/m². What intensity would a person who is standing 20 feet away hear? a) 0.81 Watts/m² b) 0.27 Watts/m² c) 0.09 Watts/m² d) 0.03 Watts/m² e) 0.01 Watts/m² Answer: The intensity changes as the square of the distance. Thus, if the distance is three times closer, as it is here (60/20 = 3), the intensity is 3² = 9 times as much. Since 0.09x9=0.81 W/m², the answer is a). Back to "Answer-This" Listing © William J. Mullin