Velocity of light By now you should have memorized the speed of light in a free space c its 29979E8 meters second or about 186000 miles per second or as a rule of thumb about one foot per nanosecond. Ce o µ o 12 eo - electric permittivity of free space - 885 x 10-12 Fm µo - magnetic permeability of free space -- 4p x 107 Hm. Whereas the permeability measures the ability of the material to allow the magnetic lines of force to pass through it.
Equation 6 As you can see the speed of light slows down in a dielectric relative to the speed in a vacuum.
Velocity of light By now you should have memorized the speed of light in a free space c its 29979E8 meters second or about 186000 miles per second or as a rule of thumb about one foot per nanosecond. Its exact value is defined as 299 792 458 metres per second approximately 300 000 kms or 186 000 mis. Where e being the absolute permittivity of free space and m being the absolute permeability of free space. And because of black holes we know that as c approaches zero ue must approach infinity.