CBSE Class 11-science Answered

Resonance takes place when the  frequency of the driving force matches the natural frequency of the system. At this instant the amplitude of oscillations becomes very large. Resonance is this phenomenon. The frequency at which resonance takes place is the resonant frequency.

In case dissipative forces are also present, then some energy of the system is lost. If damping force is small then motion is sinusoidal with a decaying amplitude and decreasing angular frequency ω.

When damping constant is small, there is little damping and the amplitude goes through a sharp peak as the driving frequency matches the natural frequency. When damping constant increases, the peak becomes broader and lesser in height which means that it is more difficult to make it resonate and the amplitude at resonance is also less.Resonance also shifts towards lower frequencies.