Question 126 of 949
If tension is maintained on a stretched string of length 0.6m, such that its fundamental frequency of 220Hz is excited, determine the velocity of the transverse wave in the string.
- A. 528 ms-1
- B. 264 ms-1
- C. 132 ms-1
- D. 66 ms-1
Correct Answer:
B
Explanation
To determine the velocity of the transverse wave in a stretched string, we can use the relationship between wave speed, frequency, and wavelength. Let's break down the problem step-by-step.
### Step 1: Understand the relationship between wave speed, frequency, and wavelength
The formula that relates wave speed (v), frequency (f), and wavelength (λ) is given by:
\[
v = f \cdot \lambda
\]
Where:
- \( v \) is the wave speed in meters per second (m/s),
- \( f \) is the frequency in hertz (Hz),
- \( \lambda \) is the wavelength in meters (m).
### Step 2: Determine the wavelength for the fundamental frequency
For a string fixed at both ends, the fundamental frequency (first harmonic) has a wavelength that is twice the length of the string. This is because the fundamental mode of vibration forms one complete wave along the length of the string.
Given:
- Length of the string \( L = 0.6 \, \text{m} \)
The wavelength \( \lambda \) for the fundamental frequency is:
\[
\lambda = 2L = 2 \times 0.6 \, \text{m} = 1.2 \, \text{m}
\]
### Step 3: Substitute the values into the wave speed formula
Now that we have the frequency and the wavelength, we can substitute these values into the wave speed formula.
Given:
- Frequency \( f = 220 \, \text{Hz} \)
- Wavelength \( \lambda = 1.2 \, \text{m} \)
Now, substituting these values into the formula:
\[
v = f \cdot \lambda = 220 \, \text{Hz} \cdot 1.2 \, \text{m}
\]
### Step 4: Calculate the wave speed
Now we perform the multiplication:
\[
v = 220 \cdot 1.2 = 264 \, \text{m/s}
\]
### Conclusion: The correct answer
Thus, the velocity of the transverse wave in the string is:
**B. 264 m/s**
### Explanation of Other Options
- **Option A (528 m/s)**: This value is incorrect because it suggests a wave speed that would require a frequency or wavelength that is not consistent with the given parameters. It could arise from a misunderstanding of the relationship between frequency and wavelength.
- **Option C (132 m/s)**: This value is also incorrect. It could be mistakenly derived from halving the correct wave speed, which does not apply in this context.
- **Option D (66 m/s)**: This option is incorrect as well. It is significantly lower than the calculated wave speed and does not align with the fundamental frequency and string length provided.
### Common Pitfalls
1. **Misunderstanding Wavelength**: Remember that for the fundamental frequency, the wavelength is twice the length of the string.
2. **Incorrectly Applying the Formula**: Ensure that you are using the correct relationship between wave speed, frequency, and wavelength.
3. **Units**: Always check that your units are consistent (e.g., meters for length, seconds for time).
### Revision Summary
- The wave speed in a stretched string can be calculated using \( v = f \cdot \lambda \).
- For a string of length \( L \), the wavelength for the fundamental frequency is \( \lambda = 2L \).
- In this case, with \( L = 0.6 \, \text{m} \) and \( f = 220 \, \text{Hz} \), the wave speed is \( 264 \, \text{m/s} \).
- Always ensure to understand the physical setup and relationships in wave mechanics to avoid common mistakes.