The diagram below shows a wire stretched over a sonometer. Stems of two vibrating tuning forks A and B are touched to the wooden box of the sonometer. It is observed that the paper rider (a small piece of paper folded at the centre) present on the wire flies off when the stem of vibrating tuning fork B is touched to the wooden box but the paper just vibrates when the stem of vibrating tuning fork A is touched to the wooden box.

(i) Name the phenomenon when the paper rider just vibrates.

(ii) Name the phenomenon when the paper rider flies off.

(iii) Why does the paper rider fly off when the stem of tuning fork B is touched to the box?

(i) The tuning fork A produces forced vibrations in the wire due to which the rider vibrates.

(ii) The tuning fork B produces resonant vibrations in the wire due to which the rider flies off.

(iii) The frequency of tuning fork B is equal to the natural frequency of wire, so resonance occurs and the wire vibrates with a large amplitude and rider flies off.