Example 1
For glass n₁ = 1.50 to air n₂ = 1.00, the critical angle is about 41.8°.
Mendeleev
Physics tools
All toolsElements
EnglishEN⌄
Languages
EnglishENFrançaisFRDeutschDEEspañolESItalianoITPortuguêsPTNederlandsNLPolskiPLSvenskaSVČeštinaCSDanskDANorskNOSuomiFITürkçeTRРусскийRUУкраїнськаUK中文ZH日本語JAБългарскиBGCatalàCAΕλληνικάELEestiETHrvatskiHRMagyarHULëtzebuergeschLBLietuviųLTLatviešuLVRomânăROSlovenčinaSKSlovenščinaSLСрпскиSR한국어KOTiếng ViệtVIBahasa IndonesiaIDBahasa MelayuMSالعربيةARहिन्दीHIไทยTHעבריתHEÍslenskaIS
Physics tools › Critical angle for total internal reflection
Mendeleev · Physics
Critical angle for total internal reflection
Total internal reflection becomes possible when light travels from a higher refractive index to a lower one. The critical angle is the incidence angle that would refract to 90°.
Formula usedsin θc = n₂/n₁
Visual cue · light ray
Calculate
Critical angle for total internal reflection
Calculated resultCritical angle
What do the symbols mean?
θccritical angle
n₁first refractive index
n₂second refractive index
Two worked examples
Example 2
For water n₁ = 1.33 to air, the critical angle is about 48.8°.
Good to knowA critical angle exists only when n₁ > n₂.