why does the light bulb glow after I turn it off

Question

(It was on for an hour)

In: 2

Answer 1

A fancier version of what /u/mysticpolka said:

Everything in the universe emits “light” (electromagnetic energy) and the amount of light it emits depends on many factors including its temperature per the Stefan-Boltzmann Law:

https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law

Note the amount of light emitted depends on the 4th power of temperature, but this only applies if you use an absolute temperature scale like Kelvin or Rankine.

Most things we see in everyday life emit too little light for us to see, unless we heat them up so they generate more light (iron gets “red hot”, copper glows green, and so on)

As mysticpolka notes, tungsten, the material inside traditional light bulbs, takes a few seconds to cool down to where the quantity of light it emits becomes too small for us to see.