Who, in 1816, modified Newton's formula for the speed of sound to take into account adiabatic compression in air?

Correct option is C

The correct answer is (c) Pierre-Simon Laplace

Explanation:

• In 1816, Pierre-Simon Laplace corrected Newton’s formula for the speed of sound in air.

• Newton assumed isothermal compression, leading to an inaccurate calculation.

• Laplace showed that sound travels through adiabatic compression, not isothermal.

• He modified Newton’s formula by including the adiabatic index (γ) of air.

• This correction aligned theoretical predictions with experimental results.

Information Booster:

• The corrected formula for speed of sound becomes:

  v = √(γ P / ρ)

• Since γ > 1, Laplace’s correction increased the predicted speed, matching observed values.

Additional Knowledge:

Lord Rayleigh (Option a)

• Made major contributions to wave theory and acoustics.

• Did not modify Newton’s formula for sound speed.

Galileo Galilei (Option b)

• Studied motion and early concepts of sound but did not address adiabatic correction.

Hermann von Helmholtz (Option d)

• Known for Helmholtz resonators and contributions to acoustics and physiology.

• Not connected to modifying Newton’s sound-speed formula.