Question

question 1 of 20 : select the best answer for the question. 1. which of the following scenarios describes a condition in which resonance can occur? a. two tuning forks that vibrate at the same frequency are near each other. one tuning fork is struck with a mallet so that it vibrates. b. a tuning fork is over a column of air that is 9/2 the wavelength of the wave produced by the tuning fork. c. two tuning forks are struck simultaneously, one with a frequency of 659hz and one with a frequency of 639 hz, causing beats. d. an isolated tuning fork is struck with a mallet, causing it to vibrate strongly at 659 hz. mark for review (will be highlighted on the review page)

Explanation:

To determine when resonance occurs, recall that resonance is the phenomenon where an object vibrates with maximum amplitude when the frequency of an external force matches its natural frequency.

• Option A: Two tuning forks with the same frequency (so natural frequency of the second matches the driving frequency from the first) near each other, with one struck. The second will resonate as the driving frequency (from the first) matches its natural frequency.
• Option B: For air column resonance, the length - wavelength relationship for a closed - end column is $L = \frac{(2n + 1)\lambda}{4},n = 0,1,2,\cdots$ and for open - end is $L=\frac{n\lambda}{2},n = 1,2,\cdots$. $\frac{9}{2}\lambda$ does not fit these resonance conditions for air columns.
• Option C: Beats are formed due to interference of two waves with slightly different frequencies, not resonance.
• Option D: An isolated tuning fork vibrating on its own is just vibrating at its natural frequency, not resonance (resonance requires an external driving force at the same frequency).

Answer:

A. Two tuning forks that vibrate at the same frequency are near each other. One tuning fork is struck with a mallet so that it vibrates.