An oscillator of natural angular frequency is driven by an external periodic force of…
PHYSICS · Subjective · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
An oscillator of natural angular frequency ω is driven by an external periodic force of variable angular frequency ωd. For three different damping constants b1<b2<b3 (light, moderate and heavy damping), answer the following:
(i) On the same set of axes, sketch three separate qualitative curves of steady-state amplitude A versus driving frequency ωd. Label the curves corresponding to b1,b2 and b3.
(ii) Explain how increasing damping affects:
(1) the maximum amplitude attained,
(2) the sharpness (width) of the resonance peak, and
(3) the frequency at which the maximum amplitude occurs.
(iii) Why is lightly damped resonance preferred in devices such as radio tuners, while heavy damping is preferred in measuring instruments such as galvanometers?