someone asked a related question http://www.thestudentroom.co.uk/show...php?p=62071773
The gaps you can see in the sun's spectrum are because the light from the sun has passed through the sun's atmosphere and the earth's atmosphere and some frequencies of light have been absorbed by atoms on the journey.
The bit that is confusing me is what it means by in the "visible and infrared". What does this mean?
the difference is that only a part of the electromagnetic spectrum is visible - IR is the radiation that's just too low in frequency to be visible.
So it just means the continuous spectrum and infrared radiation? Does this include uv radiation?
at any temperature there's an upper limit to the frequency that can be radiated - the sun has an effective temperature of about 4500 K and radiates ultraviolet... filament lightbulbs have a temperature of about 3000K and don't radiate ultraviolet
So is uv part of the continuous spectrum and only sometimes emitted whereas infared is always emitted?
note it autoscales the intensity - you still get some infrared at the highest temperatures.