# Speed of Light

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Speed of light, abbreviated as c, in a vacuum, travels at a speed of exactly 299,792,458 meters per second, or about 300,000 kilometers per second, a speed which remains constant irrespective of the speed of the source of the light or of the observer.

## Speed of Light formula

 $$\large{ c = \lambda \; f }$$

### Where:

 Units English Metric $$\large{ c }$$ = speed of light $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$\large{ f }$$ = frequency $$\large{Hz}$$ $$\large{Hz}$$ $$\large{ \lambda }$$  (Greek symbol \lambda) = wavelength $$\large{ft}$$ $$\large{m}$$

## Speed of Light in Vacuum Constant

 $$\large{ \sigma = 9.83571056 \;x\;10^{-8} \; \frac{ft}{sec} }$$ $$\large{ \sigma = 2.99792458 \;x\;10^{-8} \; \frac{m}{s} }$$

### Where:

 Units English Metric $$\large{ c }$$ = speed of light $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$