Wavelength and frequency in light are locked in a fixed relationship.
# Wave Equation
```
Speed = Wavelength • Frequency
```
$
v = f \lambda
$
> The above equation is known as the wave equation. It states the mathematical relationship between the speed (**ν**) of a wave and its wavelength (**λ**) and frequency (**f**).
This equation works for all waves: from springs, to sound, to light.
When considering light, `ν` is equal to the speed of light `c`.
$
c = f \lambda
$
# Example
Example of determining frequency from wavelength:
```math-tex
# Define Units and Constants
nm = 1e-9 # one nanometer
thz = 1e12 # one terahertz
c = 299792458 # speed of light in meters per second
λnm = 550 # 550nm
λ = λnm nm # 550nm wavelength in meters
f = c / λ # frequency in hertz
ft = f / thz # frequency in terahertz
```
# Resources
- https://www.everythingrf.com/rf-calculators/wavelength-to-frequency
- https://www.omnicalculator.com/physics/wavelength-to-frequency
# References
- https://en.wikipedia.org/wiki/Speed_of_light
- https://en.wikipedia.org/wiki/Visible_spectrum
- https://www.khanacademy.org/science/physics/light-waves/introduction-to-light-waves/a/light-and-the-electromagnetic-spectrum
- https://www.physicsclassroom.com/class/waves/Lesson-2/The-Wave-Equation