Refractive index to critical angle
Type a value in n to get it in ° instantly.
41.81°
That's 1.13× as dense as water, while window glass is 1.01× higher. Light travels 1.5 times slower inside it.
What it means
How much does it bend light?
Index depends on wavelength — that is what makes a prism work. Published values are usually for the yellow sodium line at 589 nm.
The math
How to convert n to °
From the index: the speed inside is c ÷ n, the critical angle is arcsin(1 ÷ n), Brewster’s angle is arctan(n), and the head-on reflectance is ((n − 1) ÷ (n + 1))².
Example: 1.5 n = 41.8103 °.
Every unit
Your index in every unit
Tables
n to ° conversion table
| n | ° |
|---|---|
| 1.0003 n | 88.5967 ° |
| 1.2 n | 56.4427 ° |
| 1.31 n | 49.7612 ° |
| 1.33 n | 48.7535 ° |
| 1.46 n | 43.2302 ° |
| 1.5 n | 41.8103 ° |
| 1.6 n | 38.6822 ° |
| 1.77 n | 34.4003 ° |
| 2 n | 30 ° |
| 2.42 n | 24.4075 ° |
| 3.4 n | 17.1046 ° |
° to n conversion table
| ° | n |
|---|---|
| 17.1 ° | 3.40089 n |
| 24.4 ° | 2.4207 n |
| 30 ° | 2 n |
| 34.4 ° | 1.77001 n |
| 38.7 ° | 1.59938 n |
| 41.8 ° | 1.5003 n |
| 43.2 ° | 1.46082 n |
| 48.8 ° | 1.32905 n |
| 49.8 ° | 1.30925 n |
| 56.4 ° | 1.20059 n |
| 88.6 ° | 1.0003 n |
Quick answers
Quick answers
- How many ° is 1 n?
- 1 n is 90 °.
- How many ° is 10 n?
- 10 n is 5.73917 °.
- How many ° is 1.5 n?
- 1.5 n is 41.8103 °.
The units
About these units
Refractive index (n)
How many times slower light travels in the material.
Critical angle (°)
Beyond this angle, light cannot escape the material at all.
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