# 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

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

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

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

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