(i) Frequency of sound — The speed of sound does not depend on the frequency (or wavelength) of sound wave. Hence, there is no effect on sound when the frequency of sound changes.
(ii) Temperature of air — The speed of sound in a gas increases with an increase in the temperature of the gas.
(iii) Pressure of air — The speed of sound in a gas is independent of pressure. Hence, there is no effect on sound when the pressure of air is changed.
(iv) Moisture in air — The speed of sound in air increases with an increase in the moisture level of air.
