Light has an equivolence of mass, therefore how much would a cubic metre of white light weigh (if anything), and does the mass change with colour (do different wavelengths of light have different energies and thus different mass)
The mass of a corpuscle light is in the order of approx 10^-51 kilogram. It is the Densest massive particle in the Physical Universe. The weight of a mass is a function of the gravity field in which it travels.
Light has no mass so it has no weight. BUT.... Light does have momentum so it can exert a force on a surface. Momentum of a photon = Planck's Constant / Wavelength p = h/Lambda So, if you knew the wavelength and number of photons per second you could calculate the force a beam of light exerted on a surface and if you also knew the area you could calculate the pressure.
Light has no mass. Light is just a form of energy that lets us see from it bouncing off of most objects. Sorry buddy. Its true. Light has no mass.
