| English | Resonance |
|---|---|
| Bahasa Melayu | Resonans |
| 中文 | 共振 |
Definition
The large-amplitude vibration that occurs when a system is driven at its own natural frequency.
In exam terms
Resonance is the large-amplitude vibration that occurs when a system is driven at its own natural frequency. Every object has a natural frequency at which it vibrates most easily when disturbed.
When the frequency of a driving force matches this natural frequency, energy is transferred most efficiently to the system, so the amplitude of vibration grows large. A classic demonstration is Barton's pendulums, where the pendulum whose length matches the driver swings with the greatest amplitude.
Everyday examples include pushing a swing at just the right rate and a wine glass shattering when driven at its natural frequency by sound.
Do not confuse it with natural frequency
Natural frequency is the frequency at which a system freely vibrates on its own after a single push. Resonance is what happens when an external periodic force is applied at that natural frequency, giving maximum amplitude. Natural frequency is a property of the object; resonance is an event that occurs under a matching driving force.
In Paper 2 you may be asked to define resonance, or to explain a demonstration such as Barton's pendulums. State clearly that the driving frequency equals the natural frequency and that this gives maximum energy transfer and maximum amplitude.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)