(a) Explain the term resonance and give two examples

(b)(i) Describe, with the aid of a labelled diagram, an experiment to show how the frequency of the note emitted by a vibrating string depends on the length of the string.

(ii) State two precautions necessary to obtain an accurate result.

(c) A sonometer wire is plucked and it vibrates emitting a fundamental note. State the effect on the frequency of the note if the

(i) tension in the wire were made nine times as large with no change in the length of the wire;

(ii) length of the wire were doubled with no change in the tension.