Home/Basic Physics/Waves/Intensity of a wave13. WavesIntensity of a waveIn 13. WavesFormulaCopy LaTeXI=PAI=\frac{P}{A}I=APFor an isotropic point sourceCopy LaTeXI=P4πr2I=\frac{P}{4\pi r^2}I=4πr2PTagsphysicsphysics formulawavesDetailIntensity is power per unit area; for a spherical point source, P/(4πr²).Found an error? Contact us.Related formulasRelatedAverage powerPmed=WΔtP_{\text{med}}=\frac{W}{\Delta t}Pmed=ΔtWOpen formulaOpen in sectionRelatedSound intensityI=PAI=\frac{P}{A}I=APOpen formulaOpen in section