Home Back

Angle of Incidence - Snell's Law Calculator

1. What is Snell's Law for Angle of Incidence?

Definition: Snell's Law relates the angles of incidence and refraction (transmission) when light passes between two media with different refractive indices, allowing calculation of the angle of incidence:

\[ n_1 \sin(\theta_i) = n_2 \sin(\theta_t) \] \[ \theta_i = \sin^{-1} \left( \frac{n_2}{n_1} \sin(\theta_t) \right) \]

Variables:

  • \( \theta_i \): Angle of incidence (in degrees or radians).
  • \( \theta_t \): Angle of transmission (in degrees or radians).
  • \( n_1 \): Refractive index of material 1 (where the light is coming from, dimensionless).
  • \( n_2 \): Refractive index of material 2 (where the light is entering, dimensionless).
Explanation: This equation describes how light bends when it passes from one medium to another, such as from air to glass, based on the refractive indices and the angle of transmission.

2. Importance of Snell's Law

Details: Snell's Law is fundamental in optics and physics for understanding and predicting the behavior of light as it travels between different media, used in designing lenses, prisms, and optical devices.

3. Using the Calculator

Tips: Enter the refractive indices of the two materials and the angle of transmission with its unit (degrees or radians). Click "Calculate" to get the angle of incidence in both degrees and radians.

Frequently Asked Questions (FAQ)

Q1: What is Snell's Law?
A: Snell's Law describes the relationship between the angles of incidence and refraction when light passes between two media with different refractive indices.

Q2: What is the refractive index?
A: The refractive index (\( n \)) is a dimensionless number that describes how much light slows down and bends in a medium compared to a vacuum.

Q3: What is the angle of incidence?
A: The angle of incidence (\( \theta_i \)) is the angle between the incoming light ray and the normal (perpendicular) to the surface at the point of incidence.

Q4: What is total internal reflection?
A: Total internal reflection occurs when the angle of incidence exceeds the critical angle, causing the light to reflect entirely within the first medium (when \( \sin(\theta_i) > 1 \)).

Q5: How accurate is this calculator?
A: The calculator is accurate based on Snell's Law and the input values, assuming ideal conditions. Real-world factors like dispersion or surface imperfections may introduce variations.

Angle of Incidence - Snell's Law Calculator© - All Rights Reserved 2025