スネルの法則計算機

インタラクティブな視覚化で屈折角を計算し、全反射を探索

Refraction Visualization

Red ray: incident light. Green ray: refracted light. Orange ray: total internal reflection (if applicable).

Air: 1.00, Water: 1.33, Glass: 1.52

Angle from the normal (0° to 90°)

結果

値を入力して計算をクリックして結果を表示してください。

Theory & Formula

Snell's Law describes how light bends when passing between media with different refractive indices.

Key Concepts:

  • Refraction: Bending of light at the interface between two media
  • Refractive Index: \(n\) = Ratio of speed of light in vacuum to speed in medium
  • Denser to less dense: Light bends away from normal \((\theta_2 > \theta_1)\)
  • Less dense to denser: Light bends toward normal \((\theta_2 < \theta_1)\)

Total Internal Reflection:

  • Occurs when light travels from denser to less dense medium
  • Incident angle exceeds critical angle: \(\theta_1 > \theta_c\)
  • Critical angle: \(\theta_c = \arcsin(n_2/n_1)\)
  • All light is reflected back, no refraction occurs
  • Used in optical fibers, prisms, and diamonds

Common Refractive Indices:

  • Vacuum/Air: 1.00
  • Ice: 1.31
  • Water: 1.33
  • Glass: 1.50-1.90
  • Diamond: 2.42
\(n_1 \sin(\theta_1) = n_2 \sin(\theta_2)\)

Worked Examples

Air to Water

\(n_1=1.00, n_2=1.33, \theta_1=30° \rightarrow \theta_2=22.1°\) (bends toward normal)

Water to Air

\(n_1=1.33, n_2=1.00, \theta_1=50° \rightarrow \theta_2\approx\) undefined (TIR, \(\theta_c=48.8°\))

Air to Diamond

\(n_1=1.00, n_2=2.42, \theta_1=30° \rightarrow \theta_2=11.9°\) (strong bending)
Snell's Law Calculator | MathCalcLab | MathCalcLab