This video shows how to calculate the speed that light will travel at in a material with a known value of refractive index. 30 x 10 8 meters per second ms and is the wavelength in meters m. Its a much better indicator of the bulbs luminosity than the wattage as LED lights often need less power than regular light bulbs.
Speed of light calculator for the distance per time or time per distance.
30 x 10 8 meters per second ms and is the wavelength in meters m. Next multiply the mass by the speed of light squared. Over 300 years researchers have made measurements of c and refined it. First measure the mass of the object.