Acoustic Interfaces

Intensity Fraction Squares Amplitude

Intensity reflection uses the square of the amplitude ratio. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Intensity fraction squares the amplitude ratio

The pressure ratio negative 1 over 2 has intensity fraction 1 over 4.

R2=(−12)2=14R^{2}=\left(\frac{-1}{2}\right)^{2}=\frac{1}{4}
Intensity uses the squareThe intensity label has no negative sign.incidentreflectedtransmittedleft 6 raylright 2 raylR -1/2in 4 Paback -2 Pathrough 2 PaI back 4 W/m^2

The reflected intensity is one quarter of the incident intensity

Incident intensity 16 becomes reflected intensity 4 in the checked interface ledger.

16⋅14=4 W/m216\cdot \frac{1}{4}=4\ \text{W/m}^{2}
Reflected intensityThe sign disappears only after the square.incidentreflectedtransmittedleft 6 raylright 2 raylR -1/2in 4 Paback -2 Pathrough 2 PaI back 4 W/m^2