Speed of light

Definition

The speed of light in a vacuum is the constant speed at which all electromagnetic waves propagate, approximately $3 \times 10^8$ meters per second. It is a fundamental constant in physics denoted by the symbol $c$.

5 Must Know Facts For Your Next Test

1. The speed of light in a vacuum is exactly $299,792,458$ meters per second.
2. It is denoted by the symbol $c$ and forms the basis for Einstein's theory of relativity.
3. In materials other than vacuum, the speed of light decreases depending on the refractive index of the medium.
4. The speed of light is crucial for calculating wavelengths and frequencies in electromagnetic wave equations.
5. Maxwell's equations predict that electromagnetic waves travel at the speed of light.

Review Questions

• What is the exact value of the speed of light in a vacuum?
• How does the refractive index of a material affect the speed of light within it?
• What symbol is used to represent the speed of light?

Related terms

Electromagnetic Waves: Waves composed of oscillating electric and magnetic fields that propagate through space at the speed of light.

Refractive Index: A dimensionless number that describes how fast light travels through a material compared to its velocity in a vacuum.

$\lambda (lambda)$: $\lambda$ represents wavelength, which is inversely proportional to frequency when considering waves traveling at a constant speed such as light.