RADI 143 - Ch. 8 Quiz

what percent of the electrons kinetic energy is converted to heat

99%

at what speed do electrons travel from cathode to anode

half the speed of light

what is the binding energy of the k-shell of a tungsten atom

69.5 KEV

an x-ray of the hand is taken at 55 KVP at 5 mas. How much of the x-rays produced are bremsstrahlung

100%

an x-ray of the abdomen is taken at 85 KVP at 30 mas. How much of the x-ray is produced are characteristic photons

10%

what is the efficiency of an x-ray tube using a tungsten target at 70 KVP

.518%

After finding its efficiency, how much he is produced by an x-ray tube with a tungsten target of 95 KVP

99.297%

The three principal electrical quantities that we can adjust as radiographers are

KVP, ma and time

TRUE or FALSE: during a Brems x-ray interaction at the anode, the kinetic energy lost is converted into an x-ray photon

TRUE

TRUE or FALSE: in a characteristic interaction, as long as the shell has more kinetic energy than the kinetic energy of the orbital electron, it will eject the orbital electron from its shell

FALSE

TRUE or FALSE: if the atom during a characteristic interaction begins the cascade effect and cannot fill the next electron hole, the atom is considered ionized

TRUE

TRUE or FALSE: during the cascade effect, energy released from the ejection of an orbital will be in the form of an x-ray

TRUE

brems x-rays are

heterogeneous and polyenergetic and a single electron can cause numerous brems interactions

For x-ray production to occur, four conditions are needed. What are they

there must be a source of electrons from filament wire, including the process of thermionic emission, there must be high potential difference KVP between cathode and anode, must have focusing cup to focus electrons, high speed thermion's must be stopped rapidly at the focal track of the anode

TRUE or FALSE: The glass envelope increases the life of the tube and prevents oxidation of the filament, and it also serves to prevent collision of the electrons with water molecules

FALSE

at what point in the circuit during x-ray production does electrical potential energy charge to kinetic energy

when KVP is applied to the thermionic cloud and it crosses the gap

brems

x-ray photons energy is determined by the difference between entering and exiting kinetic energy of electron

characteristic

as long as electron has more kinetic energy than the binding energy of the orbital electron, it will eject the orbital electron from the shell

Brahms interactions occurs when

The incident electron interacts with the nucleus of the atom

characteristic interactions occur when

The incident electron interacts with an inner shell electron of the target atom