No this is not a philosophical treatise, but a few facts about light bulbs to hopefully make it a bit easier for you to buy the right kind the next time you need a replacement bulb so you don’t have to rely on the light from the screen of your computer.
We all know the incandescent light bulb that has been the main stay for lighting most people’s homes and probably still persists simply because we are used to it and we like the colour of the light and we understand what we get by way of light output when we buy a 40W or 100W bulb. They are glass bulbs with a filament that is heated by electricity till it glows producing the light.
We also know that the bulbs have a limited lifespan and some less or more than others. We don’t sit down calculating the cost of using the bulb in terms of electricity [or do you?] although we know that they cost 4 to 5 times that of other types, so the others could save us quite a bit of money over a year or longer.