Physics Ontology

One map of physics, three ways in. Drill down on any quantity to see its units, the equations it lives in, and how its values span the universe.

Quantities Areas & Equations Timeline

← Back to all quantities

n

Optics

Refractive Index

Ratio of light speed in vacuum to that in a medium.

SI unit

dimensionless (—)

Dimension: $[\,1\,]$

Other units

dimensionless (—)

Order of magnitude

How values of refractive index span the physical world (in —, log scale).

Vacuum

10⁰ —

Water

1.33 × 10⁰ —

Diamond

2.42 × 10⁰ —

Lower limit10⁰ —Upper limit4.00 × 10⁰ —

Appears in 2 equations

Snell's Law

n_1 \sin\theta_1 = n_2 \sin\theta_2

Critical Angle

\sin C = \dfrac{1}{n}