Question

What are the factors that affect the speed of sound in gases?

Answer 1

In the case of gases, the following factors affect the velocity of sound waves.

1. Effect of density: The velocity of sound in a gas is inversely proportional to the square root of the density of the gas. Hence, the velocity decreases as the density of the gas increases.
   v ∝ `1/"d"`
2. Effect of temperature: The velocity of sound in a gas is directly proportional to the square root of its temperature. The velocity of sound in a gas increases with the increase in temperature v ∝ √T. Velocity at temperature T is given by the following equation:
   V_r = (v_o + 0.61 T)ms^-1.
   Here, v_o is the velocity of sound in the gas at 0° C. For air, v_o = 331 ms^-1. Hence, the velocity of sound changes by 0.61 ms^-1 when the temperature changes by one degree Celsius.
3. Effect of relative humidity: When humidity increases, the speed of sound increases. That is why you can hear sound from long distances clearly during rainy seasons.