Problem Analysis and Solution
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Question 7:
Diagram shows three types of sound waves generated from a speaker. Which of the following statements is true?
The diagram shows three sound wave patterns labeled as \( P \), \( Q \), and \( R \). The key to solving this question lies in understanding the relationship between the
frequency of a sound wave and its
pitch.
-
Pitch is determined by the
frequency of the sound wave.
-
Frequency is inversely proportional to the wavelength of the wave. A higher frequency corresponds to a shorter wavelength, and vice versa.
- In the diagrams:
- \( P \) has the longest wavelength (fewest cycles in the given space).
- \( Q \) has a shorter wavelength than \( P \) (more cycles in the same space).
- \( R \) has the shortest wavelength (most cycles in the same space).
From this, we can deduce:
- \( P \) has the lowest frequency and thus the lowest pitch.
- \( Q \) has a higher frequency than \( P \) and thus a higher pitch.
- \( R \) has the highest frequency and thus the highest pitch.
Now, let's evaluate the options:
1.
a) \( P \) has a higher pitch than \( Q \)
- False, because \( P \) has a longer wavelength and thus a lower frequency/pitch than \( Q \).
2.
b) \( Q \) has a higher pitch than \( R \)
- False, because \( R \) has a shorter wavelength and thus a higher frequency/pitch than \( Q \).
3.
c) \( R \) has the highest pitch
- True, because \( R \) has the shortest wavelength and thus the highest frequency/pitch.
4.
d) \( P \), \( Q \), and \( R \) have the same pitch
- False, because the wavelengths are different, indicating different frequencies and pitches.
Correct Answer: c) \( R \) has the highest pitch
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Question 8:
A longer string makes a ______ pitch than a short string.
This question relates to the physics of vibrating strings (e.g., guitar or violin strings). The pitch of a vibrating string depends on its length, tension, and mass per unit length. For a given tension and mass per unit length:
- A
longer string vibrates more slowly (lower frequency) and produces a
lower pitch.
- A
shorter string vibrates more quickly (higher frequency) and produces a
higher pitch.
Thus, a longer string makes a
lower pitch than a short string.
Correct Answer: c) Lower
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Question 9:
If a sound has a high frequency then it also has a ______.
This question tests the relationship between frequency and pitch:
-
Frequency is the number of wave cycles per second (measured in Hertz, Hz).
-
Pitch is the perception of how high or low a sound is, which is directly related to frequency. A higher frequency corresponds to a higher pitch, and a lower frequency corresponds to a lower pitch.
-
Volume (or loudness) is unrelated to frequency; it depends on the amplitude of the sound wave.
Given this, if a sound has a high frequency, it will also have a
high pitch.
Correct Answer: a) High pitch
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Final Answers:
1.
Question 7: \(\boxed{c}\)
2.
Question 8: \(\boxed{c}\)
3.
Question 9: \(\boxed{a}\)
Parent Tip: Review the logic above to help your child master the concept of physics sound worksheet.
