Video Transcript
The diagram shows a Coolidge tube
used for the production of X-rays. Which of the following is emitted
from the component labeled II? (A) Electrons, (B) positrons, (C)
ions, (D) X-rays, or (E) nothing.
The labeled components in this
Coolidge tube are I, a cathode coil, and II, an anode target. The negatively charged cathode coil
is powered by a potential difference causing it to heat up and emit electrons in a
process called thermionic emission. So component I, the cathode coil,
emits electrons, not component II. So answer (A) is not it. And despite being positively
charged, the anode target does not emit positrons like the cathode coil emits
electrons, so (B) is not the correct answer either.
Instead, what happens is that the
difference in charge potential between the cathode coil and the anode target causes
the electrons from the coil to accelerate towards the anode target. And when these electrons strike the
target, X-rays are produced either through Bremsstrahlung or energy level
transitions. X-rays and indeed all photons do
not have a charge. So answer (C), ions, is not it. The correct answer for which of the
following is emitted from the component labeled II, which is the anode target, is
(D) X-rays.
