If 1m is the distance travelled by a photon in #1/cs# and 1s is the time taken for light to travel #c# #m#, then what are the other SI units based on including phsyical constants?

1 Answer
Oct 14, 2017

Most are (or can be) based on real combinations of a unit force, unit distance and unit time.

Explanation:

The units that cannot involve things like the candela, the Kelvin and the kilogram (oh, what a pain that unit is!)

There's a comprehensive, but rather dry, discussion here http://www.npl.co.uk/reference/measurement-units/si-base-units/

And an excellent diagram here:

enter image source here https://physics.nist.gov/cuu/Units/SIdiagram.html