can someone please explain what is meant by this graph of black body radiation, i thought id just started to understand blackbody radiation, but i dont get what the axises mean in the graph. very much appreciated if someone could explain the features of it thanks.
Hey! Sure thing, I'll try and make it super simple
So what we are looking at here is radiation curves for black bodies (which is, for the most part, the same thing as the thermal radiation given off by everyday objects, even you and I). Black bodies emit radiation at all frequencies - Meaning you and I (assuming we are black bodies, which we aren't, but you know, dramatic effect) are emitting X-rays right now. The issue is
how much X-ray radiation is being emitted.
That's what these curves show. The horizontal axis is wavelength, the vertical is
intensity, which is just (speaking basically) how much of each wavelength we get. So if we look at the red line, there is a HEAP of energy at the 0.5 micrometer wavelength, but not much at all at the 2 micrometer wavelength. This means that it emits a lot of 0.5 micrometer radiation, not a lot of 2 micrometer radiation.
Every black body has what is called a
characteristic frequency/wavelength. This is just the wavelength/frequency where a black body emits the MOST radiation.
The different lines represent bodies of different temperatures - Indeed, for ideal black bodies, the
only thing affecting the characteristic wavelength is the temperature. Objects with higher temperatures have lower characteristic wavelengths (and higher characteristic frequencies, by the \(c=f\lambda\) formula)
Let me know if I can clarify any of this for you!
I tried to keep it as simple as I could but definitely happy to help pick any bits of it apart that you'd like