The Speed of Light as a Defining Constant
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
The speed of light in a vacuum is a fixed defining constant, exactly 299,792,458 meters per second by international definition of the meter.
Show
For any electromagnetic wave, multiplying its wavelength by its frequency always returns this same fixed speed, c = λν.
Watch for
This speed is fixed by definition, not a measured value some future experiment could revise, unlike an ordinary physical property.