How it is calculated
The angles are measured from the normal to the surface, in degrees, not from the surface itself. Water is about 1,33 and glass about 1,5.
n1 × sin θ1 = n2 × sin θ2
Where the numbers come from
- Index of the first medium
- Angle of incidence — unit in the field: °
- Index of the second medium
Example
From air n = 1 into glass n = 1,5 at 45°, the angle of refraction is about 28,1°.
Questions
Total reflection?
That is what the calculator writes when the angle leaving a denser medium is too large.
Angle of 0?
A ray along the normal is not bent.
Color of the light?
The index depends a little on the wavelength. Enter the n you need.