How is E-M radiation produced?

  1. Accelerate charged particles back and forth like they do at the radio station.

  2. All objects with temperature above "absolute zero" emit E-M radiation.

Wien's Law

The way the peak of the Planck curve changes with temperature is quantified by Wien's Law .

Temp(K) =   0.29

max(cm) =   0.29

This is Powerful!

Q. What about radiation from humans?

Note that the radiation we are all using to see one another is reflected from the lights in the room. (Don't believe me? Turn off the lights and see what you see...)

Thumans ~ 300K

max(cm) =   0.29
  = 9.8 x 10-4

= 9.8 µm implies Infrared

This is bad news for soldiers and out-of-bounds campers in Yosemite!

Q. What temperature needs to be reached for the Planck radiation of a solid to peak in the x-ray region (~ 10-9 cm)?

TX =   0.29
  = 2.9 x 108 K

Note: solids don't ordinarily get this hot!