Concept explainers
(a)
The intensity in watts per square.
(a)
Answer to Problem 57E
The intensity in watts per square is
Explanation of Solution
Write the expression for intensity level of sound.
Here,
Given that the intensity level of sound is
Apply the above condition in equation (I), and rearrange to find
Since the lowest audible intensity is equal to
Conclusion:
Therefore, the intensity in watts per square is
(b)
The intensity level in decibels
(b)
Answer to Problem 57E
The intensity level in decibels
Explanation of Solution
Write the relation between acoustic power in terms of intensity.
Here,
From subpart(a), the intensity of sound at
Use the above condition in equation (III).
Write the expression for intensity of sound at a distance of
Here,
Use equation (IV) in the above equation.
Write the expression for intensity level of sound at a distance of
Here,
Conclusion:
Substitute
Therefore, the intensity level in decibels
(c)
The output power of the radio in watts that is spread uniformly from a forward hemisphere.
(c)
Answer to Problem 57E
The output power of the radio in watts that is spread uniformly from a forward hemisphere is
Explanation of Solution
Write the expression for acoustic power from a hemisphere.
Here,
Conclusion:
Substitute
Therefore, The output power of the radio in watts that is spread uniformly from a forward hemisphere is
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Chapter 22 Solutions
General Physics, 2nd Edition
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