Question

Q31) Explain Newton's formula for velocity of sound. What is its limitation.​

Answer 1

NEWTON'S FORMULA FOR VELOCITY OF SOUND:

• Sound is a longitudinal pressure wave in which the direction of vibration of medium particles is parallel to the direction of propagation of wave.

• Now, Newton considered this propagation of wave to be a isothermal process in which there is enough time for exchange of heat with the surroundings.

Considering this thermodynamic process he calculated the formula for velocity of sound as follows:

$\boxed{v = \sqrt{ \dfrac{RT}{M} } }$

• 'R' is gas constant, 'T' is temperature, 'M' is mass of gas.

Limitations of this formula:

• If the necessary values of each of the components is put in the equation, the theoretical value of velocity of sound does not match with the practical value.

Answer 2

Limitations of velocity of sound:

P is 332 m/s. Thus, there is a considerable difference between the value predicted by Newton's formula and the experimental value. The experimental value is 16% greater than the value given by the formula. Newton failed to provide a satisfactory explanation for the difference.