# Critical Frequencies Measurement:

Coincidence frequency is defined as the Optimum efficiency that is achieved when the plate is vibrated
such that the wavelength of flexural waves in the plate is equal to the wavelength of acoustic
waves in the air , also called critical frequency.
Use this calculator for the measurement of critical frequencies of a given plane.

## Coincidence Frequency Measurement

Code to add this calci to your website

#### Formula:

f _{c} = [ sqrt(3)c^{2}/pi*d ] * [ sqrt(ρ/Y) ]
**where,**
f_{c} = Coincidence Frequency [Hz]
c = Speed of sound in air [ms^{-1}]
d = Thickness of panel [m]
ρ = Density of panel [kgm^{-3}]
Y = Youngs modulus of panel [Nm^{-2}]
This tool will help you dynamically to measure the critical frequencies of a plane online.