v = √(γRT/M)
where:
* v is the velocity of sound (in meters per second, m/s)
* γ is the adiabatic index (for air, γ ≈ 1.4)
* R is the ideal gas constant (8.314 J/mol·K)
* T is the temperature in Kelvin (K)
* M is the molar mass of air (approximately 0.029 kg/mol)
Explanation:
* Adiabatic Index (γ): This represents the ratio of specific heats at constant pressure and constant volume. For air, it's approximately 1.4.
* Ideal Gas Constant (R): This constant relates pressure, volume, temperature, and the number of moles of a gas.
* Temperature (T): The velocity of sound increases with temperature.
* Molar Mass (M): This is the mass of one mole of air molecules.
Simplified Formula:
For practical purposes, a simplified formula can be used:
v ≈ 331.5 + 0.6T
where:
* v is the velocity of sound (in meters per second, m/s)
* T is the temperature in Celsius (°C)
Note: This simplified formula is valid for temperatures near room temperature.
Example:
To calculate the velocity of sound in air at 20°C:
Using the simplified formula:
v ≈ 331.5 + 0.6(20)
v ≈ 343.5 m/s