Open Question
(I) The two pulses shown in Fig. 15–37 are moving toward each other. (c) In Fig. 15–37, at the moment the pulses pass each other, the string is straight. What has happened to the energy at this moment?
<IMAGE>
18. Waves & Sound
Wave Interference
Multiple Choice
Suppose you are listening to two tones, one of 50Hz, and the other of 10,000 Hz. If the sources of these tones are equal in intensity at your location, which do you perceive to have a higher sound intensity level (in dB), and by what factor?
A
The 50 Hz tone seems 40 times louder than the 10,000 Hz tone.
B
The 50 Hz tone seems 1000 times louder than the 10,000 Hz tone.
C
The 10,000Hz tone seems three times louder than the 50Hz tone.
D
The 10,000Hz tone seems 40 times louder than the 50Hz tone.
E
If the intensities are the same, they will seem to have the same sound intensity level.
F
The 50 Hz tone seems three times louder than the 10,000 Hz tone.
Verified step by step guidance1
Understand that sound intensity level in decibels (dB) is a logarithmic measure of the intensity of a sound relative to a reference level. The formula to calculate the sound intensity level is: \( L = 10 \log_{10} \left( \frac{I}{I_0} \right) \), where \( L \) is the sound intensity level in dB, \( I \) is the intensity of the sound, and \( I_0 \) is the reference intensity.
Recognize that the perception of loudness is not only dependent on the intensity but also on the frequency of the sound. Human ears are more sensitive to certain frequencies, typically around 2,000 to 5,000 Hz, and less sensitive to very low or very high frequencies.
Given that the sources of the tones are equal in intensity, the perceived loudness will depend on the frequency response of the human ear. The 50 Hz tone and the 10,000 Hz tone have the same physical intensity, but they will be perceived differently due to the ear's frequency sensitivity.
Consider the options provided. The statement 'The 50 Hz tone seems three times louder than the 10,000 Hz tone' suggests that despite having the same intensity, the lower frequency tone is perceived as louder. This is consistent with the fact that lower frequencies can sometimes be perceived as louder due to the way sound waves interact with the environment and the ear's response.
Conclude that the correct perception of loudness is influenced by both the physical intensity and the frequency of the sound. Therefore, the statement 'The 50 Hz tone seems three times louder than the 10,000 Hz tone' is the correct interpretation of how these tones are perceived, given the same intensity.
Related Videos
Related Practice
