Which condition must be met for resonance to occur in a system?

• A. The system must be in a vacuum.
• B. The energy supply must be constant.
• C. The driving frequency must match the system’s natural frequency.
• D. The sound must be produced by multiple sources.

Answer: (C)

Resonance occurs in a system when the driving frequency matches the system's natural frequency. This is a fundamental principle in the study of wave behavior and resonance, where an external force or frequency is applied to a system. When the frequency of this external force aligns with the natural frequency of the system, it results in a significant increase in amplitude. This principle can be observed in various physical contexts, such as tuning forks, musical instruments, and even structural engineering.

In this scenario, when the driving frequency is in sync with the system’s natural frequency, the system can store and transmit energy more efficiently. This condition is critical for resonance to take place, leading to the creation of larger oscillations than would occur with a mismatched frequency. This concept is essential in understanding not only sound production but also a wide range of physical phenomena, from bridges vibrating due to passing vehicles to the mechanics of musical instruments.