While tuning his guitar, a student performs two separate actions.
(i) First he tightens one string and then plucks it exactly as before. Explain qualitatively how the sound heard changes. Give reasons with reference to the physical quantity altered.
(ii) Next he plucks the same tightened string much harder without changing its tension. Explain the change heard this time and the physical quantity responsible.
(iii) A flute and a drum both emit notes of the same frequency and amplitude. Yet they are easily distinguished. Name the property that helps to differentiate the two sounds and state why this property is not determined by frequency or amplitude.