X-rays Flashcards
what are X-rays
em waves with a very short wavelength. able to penetrate soft body tissue. we can use them to produce images of the bones and organs within the body
how do X-rays become ionised. What happens to them
as x-rays pass through body tissue they can be absorbed by molecules, and the molecules become ionised. in this process the x-rays lose energy and eventually cannot ionise any more tissue
how are X-rays produced
in a X-ray machine
Explain the key features of passing a current through an
evacuated tube, including:
a thermionic emission of electrons from a heated filament
b potential difference between the cathode (filament) and the anode (metal target)
c why the vacuum is necessary
d possible production of X-rays by collision with a metal target
in an x-ray machine electrons are produced by a cathode, which is heated by a filament inside an evacuated tube. the electrons accelerate towards an anode because of the very high potential difference between the anode and the cathode. embedded in the anode is a tungsten target and when very energetic electrons strike the target some of this energy is converted into x-rays. the vacuum means there are no gas molecules to scatter and absorb the energy of electrons striking the target
