In which scenario is resonance most likely to be observed?

• A. A closed tube filled with air
• B. A string vibrating at its fundamental frequency
• C. A system experiencing external noise
• D. A vacuum chamber without any air

Answer: (B)

Resonance is most likely observed in systems where the natural frequency of oscillation matches the frequency of an external force or input. In the case of a string vibrating at its fundamental frequency, the system is set to oscillate at its inherent mode of vibration, which is the lowest frequency at which the string can vibrate. When external stimuli are in sync with this fundamental frequency, a notable amplification of the oscillation occurs, demonstrating resonance.

In contrast, while a closed tube filled with air can support standing waves, resonance in a tube would depend on specific frequencies that match the dimensions of the tube. External noise may introduce a variety of frequencies, but it does not guarantee resonance unless those frequencies resonate harmonically with the system. Lastly, resonance cannot occur in a vacuum chamber without air, as there are no medium particles to propagate sound waves and generate oscillations. Thus, a vibrating string at its fundamental frequency is the clearest example of resonance in action.