Optics
Critical Angle
The angle of incidence above which total internal reflection occurs (when going from denser to less dense medium).
Variables
\theta_c°
Critical angle
n_1unitless
Refractive index of denser medium
n_2unitless
Refractive index of less dense medium
Your notes
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Common questions
What is the Critical Angle formula?
Critical Angle is written sinθ_c = n₂/n₁. The angle of incidence above which total internal reflection occurs (when going from denser to less dense medium). It belongs to Optics, under Refraction.
What are the units in sinθ_c = n₂/n₁?
In SI units, \theta_c is critical angle, measured in °; n_1 is refractive index of denser medium (dimensionless); n_2 is refractive index of less dense medium (dimensionless).