Question

A student carrying an experiment discovered that it took 2 seconds for a sound wave traveling through a telephone line to cover a distance d meters and 20 seconds for the same sound traveling through air to cover a similar distance. Determine the ratio of speed of sound in air to that in the wire

Answer 1

By definition, the speed of sound in the wire:

$$v_w = \dfrac{d}{2s}$$

The speed of sound in air:

$$v_a = \dfrac{d}{20s}$$

Their ratio is:

$$\dfrac{v_a}{v_w} = \dfrac{d\cdot 2s}{20s\cdot d} = \dfrac{2}{20} = \dfrac{1}{10} = 0.1$$

Answer. 0.1.