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Question at position 5  You will now simulate portions of Procedure 1.3.1 from Lab 9. Return to the PhET – Wave on a String Links to an external site. simulation. Click the Reset Button . Set the wave driver to "Oscillate" (upper-left corner), click the Pause Button and then the Restart Button . Now, adjust the simulation's settings as follows: Set the Amplitude to 0.05 cm. Set the Frequency to 1.00 Hz. Set Damping to None. Set Tension to High. (The Fixed End option should already be selected.) Click the Play Button to turn on the wave driver. Observe the wave on the string for 30 seconds. When finished, click the Pause Button and then the Restart Button. Adjust the frequency to 1.05 Hz. Click the Play Button and again observe the wave on the string for 30 seconds. Repeat this process for increments of 0.05 Hz until you reach 1.35 Hz. Ensure you press the Restart Button before adjusting the frequency. Which of the following statements are true? Select all statements that are true. The frequency of the third harmonic is approximately 1.25 Hz.When the string is in the third harmonic, the second, fourth, and sixth green balls from the left are at antinodes.Let λ3\lambda_3 be the wavelength of the third harmonic. When the string is in the third harmonic, the string contains three half wavelengths (i.e., 3(λ2)=L3(\frac{\lambda}{2})=L).When the string reaches the third harmonic, the amplitude of the standing wave maximizes.When the string is not in a harmonic, the standing wave's amplitude is irregular and, at moments, dies out. In other words, the wave's amplitude increases and decreases over time.

选项
A.The frequency of the third harmonic is approximately 1.25 Hz.
B.When the string is in the third harmonic, the second, fourth, and sixth green balls from the left are at antinodes.
C.Let 𝜆 3 be the wavelength of the third harmonic. When the string is in the third harmonic, the string contains three half wavelengths (i.e., 3 ( 𝜆 2 ) = 𝐿 ).
D.When the string reaches the third harmonic, the amplitude of the standing wave maximizes.
E.When the string is not in a harmonic, the standing wave's amplitude is irregular and, at moments, dies out. In other words, the wave's amplitude increases and decreases over time.
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思路分析
To evaluate the statements, I will go option by option and explain the reasoning that supports or undermines each. Option 1: The frequency of the third harmonic is approximately 1.25 Hz. - In a string with fixed ends, the harmonics occur at integer multiples of the fundamental frequency: f_n = n f_1. If, during the frequency sweep described, a third-harmonic response is observed around 1.25 Hz, this is consistent with the idea that the driving frequency has reached about three times the fundamental. Since the experiment steps in 0.05 Hz increments starting at 1.00 Hz, reaching 1.25 Hz is indeed possible (1.00, 1.05, 1.10, 1.15, 1.20, 1.25, ...). Therefore, stating that the third harmonic frequency is approximately 1.25 Hz is plausible and consistent wit......Login to view full explanation

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