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Waves
Waves

Reflection Coefficient

R=(v2−v1v2+v1)2R = \left(\frac{v_2 - v_1}{v_2 + v_1}\right)^2

Fraction of wave power reflected at boundary between two media.

Variables

R
Reflection coefficient
Fraction of power reflected (0-1)
unitless
v₁
Wave speed in medium 1
Incident medium
m/s
v₂
Wave speed in medium 2
Transmitted medium
m/s

Derivation

From continuity of displacement and force at boundary. R = ((Z₂-Z₁)/(Z₂+Z₁))² where Z = ρv.

Your notes

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Common questions

What is the Reflection Coefficient formula?

Reflection Coefficient is written R = (v₂ - v₁/v₂ + v₁)². Fraction of wave power reflected at boundary between two media. It belongs to Waves, under Wave Properties.

What are the units in R = (v₂ - v₁/v₂ + v₁)²?

In SI units, R is reflection coefficient (dimensionless); v₁ is wave speed in medium 1, measured in m/s; v₂ is wave speed in medium 2, measured in m/s.

How is the Reflection Coefficient formula derived?

From continuity of displacement and force at boundary. R = ((Z₂-Z₁)/(Z₂+Z₁))² where Z = ρv. The result is R = (v₂ - v₁/v₂ + v₁)².