Newton Laplace Formula For Speed Of Sound — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Newton-Laplace Formula for Speed of Sound Applies to ideal gases where sound propagation is modeled as an adiabatic process. Start with the general bulk modulus formula v = sqrt(B/rho). Assume the compressions and rarefactions occur fast enough to be adiabatic. Use the adiabatic condition PV gamma = constant. Differentiate to find the adiabatic bulk modulus B adiabatic = gamma P. Substitute B with gamma P. Gas behaves as an ideal gas. Process is adiabatic (heat exchange is negligible compared to wave speed). Small amplitude waves. Assuming the process is isothermal (Newton's original error), which omits gamma. Believing pressure changes alone affect sound speed (density usually changes proportionally, cancelling the effect unless temperature changes). Confusing particle velocity with wave velocity.