Fresnel Reflection (Normal Incidence)
For light at normal incidence, the Fresnel equations simplify to give the reflection coefficient. R gives the fraction of intensity reflected.
Variables
Derivation
Derived from Maxwell's equations by applying boundary conditions at the interface between two media.
Your notes
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- n1 = 1.5 (Refractive index of incident medium)
- n2 = 2.5 (Refractive index of transmitted medium)
Result: R = 0.0625
Where this formula is listed
- Optics formulas, under Reflection, alongside Law of Reflection, Mirror Equation, Mirror Magnification, Focal Length and Radius and Spherical Mirror Focal Length.
- In the optics list it comes after Focal Length and Radius and before Spherical Mirror Focal Length.
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Fresnel Reflection (Normal Incidence) formula?
Fresnel Reflection (Normal Incidence) is written r = (n₁ − n₂)/(n₁ + n₂), R = r². For light at normal incidence, the Fresnel equations simplify to give the reflection coefficient. R gives the fraction of intensity reflected. It belongs to Optics, under Reflection.
What are the units in r = (n₁ − n₂)/(n₁ + n₂), R = r²?
In SI units, r is amplitude reflection coefficient (dimensionless); R is reflectance (intensity) (dimensionless); n₁ is refractive index of incident medium (dimensionless); n₂ is refractive index of transmitted medium (dimensionless).
How is the Fresnel Reflection (Normal Incidence) formula derived?
Derived from Maxwell's equations by applying boundary conditions at the interface between two media. The result is r = (n₁ − n₂)/(n₁ + n₂), R = r².