Critical Angle Calculator

Calculate the critical angle for total internal reflection at interfaces

Results

Critical Angle
41.8103°
n1 (denser)
1.5000
n2 (less dense)
1.0000
Brewster Angle (for comparison)
33.6901°
Speed Ratio (v2/v1)
1.5000

Applications of Total Internal Reflection

  • Optical Fibers: Light guided through fiber core
  • Prisms: Total reflection in binoculars and periscopes
  • Diamond Brilliance: Multiple internal reflections create sparkle
  • Endoscopes: Medical imaging through fiber bundles
  • Reflectors: Cat's eyes and road reflectors

Common Critical Angles

  • Glass-to-Air: ~42°
  • Water-to-Air: ~49°
  • Diamond-to-Air: ~24°
  • Optical Fiber (typical): ~82°

Formula Used

sin(θc) = n2 / n1

θc = arcsin(n2 / n1)

Condition: n1 must be greater than n2