Please, I need your help to answer these 3 questions 100 keV electrons lose ener
ID: 1366864 • Letter: P
Question
Please, I need your help to answer these 3 questions
100 keV electrons lose energy in an x-ray target via: production of characteristic radiation production of bremsstrahlung radiation heat loss Rank these three modes of energy loss in order of decreasing magnitude: The voltage applied to an X-ray tube is 150 kVp. The energy of bremsstrahlung radiation produced is: Fill in the blank: An atom has a K-shell binding energy of 70 keV, an L-shell binding energy of 8 keV and an M-shell binding energy of 1 keV. If an electron spontaneously makes a transition from the K-shell to the L-shell, the emitted radiation will be keV.Explanation / Answer
Solution:
Q 11:
Solution: When a certain number of electron having 100 keV kinetic energy are bombarded at on the target nucleus then most of the electrons undergo inelastic collision meaning the collision whose output is just waste heat. It is observed that only about 1% of the electric energy supplied to the X-ray tube is converted into useful X-rays. Thus heat loss the primary way in which electrons loose energy.
When the electrons are slowed down, suddenly stopped or deviated by the target nucleus, then the kinetic energy of the electron takes place. The change in the kinetic energy is converted into X- ray photon which has the energy equal to difference between the final and initial kinetic energy. This is the primary source of X-rays hence it electrons must be losing energy via this process. This process is called Bremsstrahlung radiation and it is secondary way in which electrons loose energy.
Characteristic radiation is produced when the electrons from the filament replace the inner shell electron in the target atom due to collision. The outer shell electron from the same atom jumps in to fill the void hence emits the X-ray photon whose energy is equal to the difference between the energy of the two orbits. This is the secondary source of X-ray radiation but very rare as compared to Bremsstrahlung radiation.
Thus the answer is,
100 KeV electrons losses energy through three modes of energy loss in order of decreasing magnitude;
(1) heat loss, (2) production of Bremsstrahlung radiation, (3) production of characteristic radiation.
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Q 12
Solution: When voltage applied to an X-ray tube is 150 keV then maximum energy gained by the electrons is 150 keV. Further, in a special case when electrons hit the target nucleus head on then total kinetic energy is converted into an X-ray whose energy is equal to the energy of the electron. But this kinds of collisions are bit rare and this is only procces when X-ray energy is equal to the voltage applied across the X-ray tube.. Most of the time electrons kinetic energy is changed by deviating, breaking etc. Thus answer is,
The energy of bremsstrahlung radiation produced is: (B) any value < 150 keV
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Q 13
Solution: We see that the K-shell has the binding energy of 70 keV while L-shell has the binding energy of the 8 kev. When electron spontaneously makes transition from K-shell to L-shell, the excess energy of the electron is converted into X-ray photon whose energy is equal to the energy difference between the K and L-shell; that is (70 keV – 8 keV) = 62 keV
Hence the answer is: the emitted radiation will be 62 keV