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Question
Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
Options
the kinetic energy of the striking electron
the kinetic energy of the free electrons of the target
the kinetic energy of the ions of the target
an atomic transition in the target
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Solution
the kinetic energy of the striking electron
In an X-ray tube, electrons are emitted by the filament when it is heated. An electric field generated by a DC battery between the filament and the target makes the electrons hit the target atoms with a very high speed. As a result, the electrons lose their kinetic energy to eject photons, which leads to a continuous emission of X-rays.
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