Understanding Beat Frequency: Equations and Solutions

AI Thread Summary
The discussion revolves around calculating beat frequency from a given graph showing wavelengths over time. Participants analyze the number of wavelengths and the time interval, leading to a calculated frequency of 50 Hz. There is confusion regarding whether this frequency represents one of the source frequencies or the resultant frequency. The consensus suggests that the calculated frequency is the average of the two source frequencies, despite discrepancies in the problem statement. Participants agree that the author may have misrepresented the beat frequency in the question.
thereddevils
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Homework Statement



See attachment.

Homework Equations





The Attempt at a Solution



f1 - f2 = 5

What's there for me to interpret in the graph?
 

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  • Beat frequency.jpg
    Beat frequency.jpg
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From the graph you can see 8 complete wavelengths. This occurs in an interval of 0.15s

therefore f=number of events(or wavelengths) / \Deltat .


R.
 
Rick88 said:
From the graph you can see 8 complete wavelengths. This occurs in an interval of 0.15s

therefore f=number of events(or wavelengths) / \Deltat .


R.

I counted 7.5 and taking a closer look the interval is 0.16.

f=8/(0.16)=50

What is this frequency? Is it the frequency of one of the sources? Or is it the resultant frequency?

By the way, the answer given is A
 
The f you calculated is the average of f1 and f2.
thereddevils said:

The Attempt at a Solution



f1 - f2 = 5
The answer choices suggest a different value for f1 - f2.
 
Redbelly98 said:
The f you calculated is the average of f1 and f2.

The answer choices suggest a different value for f1 - f2.

so the answer should be C?
 
thereddevils said:
so the answer should be C?
Based on your calculation of 50 Hz, yes. However, I recommend doing the following calculation over (can you spot the error?):
thereddevils said:
I counted 7.5 and taking a closer look the interval is 0.16.

f=8/(0.16)=50

By the way, the answer given is A
I think the author of the question is confused. They also stated the wrong beat frequency in the problem statement.
 
Redbelly98 said:
Based on your calculation of 50 Hz, yes. However, I recommend doing the following calculation over (can you spot the error?):



I think the author of the question is confused. They also stated the wrong beat frequency in the problem statement.

ok thanks all for helping.
 

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