Question

Distinguish between forced vibrations and resonance.

Answer 1

 

Sr. No.	Forced vibrations	Resonance
1	It is produced by an external periodic force of any frequency.	It is produced by an external periodic force whose frequency is equal to the natural frequency of the body
2	The frequency of vibrations is different from the natural frequency of the body	The frequency of vibrations is sa me as the natural frequency of the body.
3	The amplitude of vibration is small.	The amplitude of vibration is very large.
4	Vibrations stop as soon as the external force is removed.	Vibrations continue for some time even after the external force is removed
5	Faint sound is produced.	Loud sound is produced.

Mode of vibration of a stretched string in second harmonic:

Mode of vibration of a stretched string in third harmonic: