Angle of Incidence Calculator

Calculate angle of incidence and refraction using Snell's Law and optics principles

Optics Calculator

Choose which angle you want to calculate

Refractive index: 1.000273

Refractive index: 1.333000

Known refraction angle

Optics Results

70.44°
Angle of Incidence (θ₁)
13.9%
Light Reflected
53.12°
Brewster's Angle

Snell's Law: n₁ sin(θ₁) = n₂ sin(θ₂)

Refractive indices: n₁ = 1.000273, n₂ = 1.333000

Index ratio: n₂/n₁ = 1.332636

Optical Analysis

✅ Light traveling from rarer to denser medium - no total internal reflection

Example Calculation

Light Exiting Water

Scenario: Light ray traveling from water to air

Medium 1: Water (n₁ = 1.333)

Medium 2: Air (n₂ = 1.000273)

Angle of refraction: 45°

Solution

Using Snell's Law: sin(θ₁) = (n₂/n₁) × sin(θ₂)

sin(θ₁) = (1.000273/1.333) × sin(45°)

sin(θ₁) = 0.7502 × 0.7071 = 0.5305

θ₁ = 32.0°

The angle of incidence in water is 32.0°

Refractive Indices

Vacuum1
Air (STP)1.000273
Water1.333
Ice1.31
Crown Glass1.52
Flint Glass1.62
Quartz1.544
Diamond2.42
Oil1.515
Ethanol1.361
Glycerol1.473
Plastic (PMMA)1.49

Optical Phenomena

Refraction

Bending of light when entering new medium

Total Internal Reflection

Complete reflection at critical angle

Brewster's Angle

Angle for complete polarization

Applications

📸

Camera Lenses

Light focusing and aberration control

🔬

Microscopy

Oil immersion for better resolution

🌈

Optical Fibers

Total internal reflection for data transmission

Understanding Light Refraction

What is Angle of Incidence?

The angle of incidence is the angle between an incoming light ray and the normal (perpendicular line) to the surface at the point of contact. When light travels from one medium to another, it changes direction according to Snell's Law.

Key Principles

  • Light bends toward normal when entering denser medium
  • Light bends away from normal when entering rarer medium
  • Critical angle leads to total internal reflection
  • Brewster's angle produces completely polarized light

Snell's Law

n₁ sin(θ₁) = n₂ sin(θ₂)

  • n₁, n₂: Refractive indices of media 1 and 2
  • θ₁: Angle of incidence
  • θ₂: Angle of refraction

Critical Conditions

Critical Angle: θc = sin⁻¹(n₂/n₁)

Brewster's Angle: θB = tan⁻¹(n₂/n₁)

Total Internal Reflection: θ₁ > θc (when n₁ > n₂)

Real-World Applications

Optical Instruments

Telescopes, microscopes, cameras use refraction for image formation

Fiber Optics

Total internal reflection enables high-speed data transmission

Optical Devices

Prisms, lenses, and polarizers for various applications