Basic equation: ;
Stretched String: ()
Fundamental standing wave:
Intensity: (P is the power produced by the source and A is the area over which the power is spread.)
Decibel level: ()
Resonance for sound waves
If the far end of tube is sealed, for any odd integer n:
If the far end of tube is not sealed, for any integer n:
The Doppler effect
The shift in frequency that occures when the source and detector are in relative motion is known as the Doppler effect.
When a detector approaches a source or a source approaches a detector, the resulting frequency would increase and vice versa.