You can calculate weight by multiplying mass by the gravity on the surface of the planet.
<em>
</em>
<em>Weight = Mass x Surface Gravity
</em>
So, if you know your weight on Earth and the surface gravity on Earth, you can calculate your mass. You can then calculate your weight on any other planet by using the surface gravity of that planet in the same equation.
Only portions of the electromagnetic spectrum is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light which have wavelengths from about 390 to 750 nm that is; ultraviolet light and visible light.