Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force is equal or close to a natural frequency of the system on which it acts.
Objects, mechanical systems and charged particles tend to vibrate at a specific frequency.
We call this frequency the resonant frequency or the natural frequency.
When a light or a sound wave strikes an object that is already vibrating at some particular frequency, and if that frequency happens to match the resonant frequency of the object it’s hitting; then you’ll get what’s called resonance.
Resonance occurs when the matching vibrations of another object increase the amplitude of an object’s oscillations.onant frequency.