Bushong Chapter 8 Workbook Answers

If mass is expressed in kilograms and velocity in meters per second, kinetic energy will be expressed in:

Joules

The kinetic energy of the projectile electron in an x-ray tube:

Is about 1% efficient in production of x-rays

The shift of the characteristic x-ray spectrum to higher energy occurs because of:

An increase in target atomic number

Useful characteristic x-rays are produced in tungsten:

By removal of a K shell electron

An L-shell electron (binding energy 26 keV) is removed from an atom that has M-shell binding energy of 4 keV and N-shell binding energy of 1 keV. If a free electron fils the vacancy in the L-shell, characteristic x-ray produced will have energy of:

26 keV

What is produced when the projectile electron excites an outer-shell electron

Heat

The energy of characteristic x-rays increases with increasing:

Atomic number of target material

X-rays are produced when:

Projectile electrons interact with target atoms

Characteristic x-rays:

Are characteristic of target Z

When a tungsten-targeted x-ray tube is operated at 68 kVp:

1. K-shell characteristic x-rays cannot be produced

2. Some projectile eletrons may have 68 keV of energy

When characteristic x-rays are produced, the energy is characteristic of:

1.The atomic number of the target

2. The electron binding energy

Gold is sometimes used as target material in special types of radiation producing systems. Its electron binding energies are as follows:

K-shell: 81 keV; L-shell: 14keV; M-shell: 3 keV and N-shell: 1 keV. What characteristic x-rays would be produced with operation at 90 kVp.

67 keV

The kinetic energy of a projectile electron can be measured in:

Joules

The efficiency of x-ray production is:

Independent of tube current.

The joules of energy generated by electron target interactions are given by:

kV x mA x s

In a tunsten-targeted x-ray tube operated at 90 kVp, the most abundant x-ray would be a:

a.) 10 keV characteristic x-ray

b.) 12 keV characteristic x-ray

c.) 30 keV Bremsstrahlung x-ray

d.) 69 keV Bremsstrahlung x-ray

e.) 90 keV Bremsstrahlung x-ray

c.) 30 keV Bremsstrahlung x-ray

Which of the following electron transitions results in the most useful Bremsstrahlung x-ray?

a.) L to K

b.) M to K

c.) M to L

d.) O to K

e.) None of the above

e.) None of the above

Bremsstrahlung radiation is produced by:

a.) Conversion of projectile electron kinetic energy to electromagnetic energy.

b.) Conversion of target electron kinetic energy to electromagnetic energy.

c.) Intrashell electron transitions.

d.) Projectile electron - target electron interaction.

e.) Target electron - nuclear interaction.

a.) Conversion of projectile electron kinetic energy to electromagnetic energy.

When a Bremsstrahlung x-ray is produced:

a.) A projectile electron is absorbed.

b.) A projectile electron loses energy.

c.) A target electron is displaced.

d.) A target electron is excited.

e.) A target electron is ionized.

b.) A projectile electron loses energy.

In Bremsstrahlung x-ray production:

a.) The projectile electron is bound to tungsten.

b.) The projectile electron is from the cathode.

c.) The target electron exists as a free electron.

d.) The target electron is from the cathode.

e.) The target electron is ionized.

B.) The projectile electron is from the cathode.

If an average radiographic technique is used:

a.) Excitation of the target is approximately 50%.

b.) Ionization of the target is almost complete.

c.) Maximum-energy x-ray is the electron binding energy.

d.) Most x-rays are Bremsstrahlung.

e.) Most x-rays are characteristic.

d.) Most x-rays are Bremsstrahlung.

Bremsstrahlung x-rays are produced only at:

a.) Discrete energies.

b.) Energies above characteristic x-rays.

c.) Energies below characteristic x-rays.

d.) Energies up to projectile electron energy.

e.) Projectile electron kinetic energy.

d.) Energies up to projectile electron energy.

If radiographic technique is 74 kVp/80 mAs:

a.) Bremsstrahlung x-ray energy increases if the voltage is increased to 84 kVp.

b.) Bremsstrahlung x-rays are emitted at discrete energies.

c.) Bremsstrahlung x-rays have a maximum energy of 80 keV.

d.) Characteristic x-ray energy increases if the voltage is increased to 84 kVp.

e.) Characteristic x-rays are emitted only at 74 keV.1

a.) Bremsstrahlung x-ray energy increases if the voltage is increased to 84 kVp.

If radiographic technique is a tungsten target as 60 kVp/80 mAs is changed to 80 kVp/80 mAs:

a.) Additional filtration is required.

b.) Bremsstrahlung x-ray intensity remains unchanged.

c.) Characteristic x-ray intensity remains unchanged.

d.) The number of projectile electrons increases.

e.) The number of x-rays produced increases.

e.) The number of x-rays produced increases.

Bremsstrahlung x-rays produced in a tungsten targeted x-ray tube:

a.) Are all diagnostically useful.

b.) Are generally less useful than characteristic x-rays.

c.) Are less intense than characteristic x-rays.

d.) Are less intense than if produced in molybdenum.

e.) Outnumber characteristic x-rays.

e.) Outnumber characteristic x-rays.

When a Bremsstrahlung x-ray is emitted:

a.) A projectile electron is absorbed.

b.) An inner-shell electron is removed from the target atom.

c.) An outer-shell electron is removed from the target atom.

d.) This results from the conversion of kinetic energy.

e.) The target atom is ionized.

d.) This results from the conversion of kinetic energy.

The wavelength of an x-ray:

a.) Becomes longer as projectile electron kinetic energy is reduced.

b.) Becomes longer with increasing projectile electron energy.

c.) Is longer than that of ultraviolet light.

d.) Is longest when the projectile electron loses all its kinetic energy.

e.) Is proportional to its frequency.

a.) Becomes longer with increasing projectile electron energy.

When projectile electron energy is increased:

a.) Characteristic x-ray energy decreases.

b.) Characteristic x-ray energy increases.

c.) More Bremsstrahlung x-rays are produced.

d.) More Bremsstrahlung x-rays are produced, but only at high energies.

e.) More Bremsstrahlung x-rays are produced, but only at low energies.

c.) More Bremsstrahlung x-rays are produced.

The efficiency of Bremsstrahlung x-ray production increases with increasing:

a.) Collimation

b.) Filtration

c.) mA

d.) SID

e.) Target atomic number

e.) Target atomic number

The output intensity of an x-ray tube:

a.) Increases when filtered.

b.) Is limited by the K-shell binding energy.

c.) Is monoenergetic.

d.) Often is measured in curies (Becquerels).

e.) Is primarily due to Bremsstrahlung x-rays.

e.) Is primarily due to Bremsstrahlung x-rays.

Which of the following projectile electron-target interactions results in x-ray emission?

a.) Excitation of inner-shell electron.

b.) Excitation of outer-shell electron.

c.) Removal of inner-shell electron.

d.) Removel of nucleus.

e.) Removal of outer-shell electron.

c.) Removal of inner-shell electron.

When a projectile electron enters a target atom and interacts with the nuclear force field:

a.) It decreases in velocity.

b.) It increases in velocity.

c.) It ionizes the atom.

d.) It ionizes the nucleus.

e.) It removes an inner-shell electron.

a.) It decreases in velocity.

In a tungsten-targeted x-ray tube operated at 90 kVp, the most abundant x-ray would be a:

a.) 10 keV characteristic x-ray

b.) 12 keV characteristic x-ray

c.) 30 keV bremsstrahlung x-ray

d.) 69 keV bremsstrahlung x-ray

e.) 90 keV bremsstrahlung x-ray

c.) 30 keV bremsstrahlung x-ray

the area under the curve of the x-ray emission spectrum represents:

The total number of x-rays

Normally, the x-ray emission spectrum contains:

Both characteristic and bremsstrahlung x-rays

The characteristic x-ray emission spectrum principally depends upon:

Target material

The continuous x-ray emission spectrum principally depends upon:

Projectile electron energy

What factors explain the low number of x-rays produced at low energy?

Added filtration

The x-ray emission spectrum represents:

X-rays emitted from the x-ray tube

Both the shape and the position of the characteristic x-ray emission spectrum:

Correspond to target electron binding energies

A diagnostic x-ray beam contains:

Mostly bremsstrahlung x-rays, with some characteristic x-rays

The x-ray emission spectrum is a plot of:

The number of x-rays versus energy

The amplitude of the bremsstrahlung x-ray emission spectrum:

Has maximum value at energy approximaely 1/3 of the kVp

If an x-ray emission spectrum represented operation at 85 kVp with a tungsten target:

The K-characteristic x-ray emissionwould occur at 69 keV

If an x-ray emission spectrim represented operation at 26 kVp with a molybdenum target:

The characteristic radiation would have energy of approximately 19 keV

Which of the following factors principally accounts for the reduced x-ray intensity at low energy?

Added filtration

Characteristic x-radiation is related to the:

Energy required to eject K-shell electrons

Molybdenum has a lower atomic number than tungsten; therefore, the molybdenum x-ray emission spectrum:

Has lower amplitude

To construct an x-ray emission spectrum, one must know the:

Number of x-rays at each energy interval

Which characteristic is reduced as x-ray energy increases?

X-ray wavelength

The wavelength of an x-ray is:

Inversely proportional to its energy

The product of Planck's constant (h) and the velocity of light (c) has units of:

Jm

The product of Planck's constant (h) and the velocity of light (c) equals:

12.4 x 10^-7 eVm

If one knows the minimum wavelength of a given x-ray beam, the kVp of operation can be determined if one also knows:

Planck's constant & The speed of light

The relationship of minimum wavelength to maximum x-ray energy is sometimes called the:

Duane-Hunt law

Minimum wavelength is related to :

The kinetic energy of the projectile electron

That region of the x-ray emission spectrum associated with minimum wavelenth is the:

Highest-energy bremsstrahlung x-ray

If one knows the minimum wavelength of an x-ray emission spectrum, one can calculate:

Maximum projectile electron energy

To calculate minumum x-ray wavelength, one must know the value of:

kVp

How would the total emission spectrum be affected by operation at 80 kVp/400 mA/100ms

Remain the same, but the amplitude would decrease

How would the emission spectrum be affected by the addition of 2 mm Al filtration? The relative position of the spectrum would:

Shift to the right, and the amplitude would be lower

How would the emission spectrum be affected if the power supply were changed from single phase to three phase? The relative position of the spectrum would:

Shift to the right, the amplitude would increase, and the characteristic lines would increase in height

Which of the following statements applies to the x-ray emission spectrum?

a. adding filtration affects characteristic x-ray energy

b. adding filtration affects minimum wavelength

c. adding filtration increases entrance skin exposure

d. the target material affects the amplitude of bremsstrahlung x-rays

e. the target material affects the minimum wavelength

D

An increase in mAs results in an increase in:

a. average x-ray energy

b. both characteristic and bremsstrahlung x-rays

c. minimum wavelength

d. only the bremsstrahlung x-rays

e. only the characteristic x-rays

B

An increase in kvp results in an increase in:

a. characteristic x-ray energy

b. only the bremsstrahlung x-ray emission spectrum

c. only the characteristic x-ray emission spectrum

d. radiation quality

e. minimum wavelength

D

The intensity of x-ray exposure is best represented by:

a. the amplitude of the bremsstrahlung x-ray emission spectrum

b. the amplitude of the characteristic x-ray emission spectrum

c. the amplitude of the highest emission spectrum

d. the area under the emission spectrum

e. the energy range of the emission spectrum

D

Which of the following factors primarily affects the low energy side of the x-ray emission spectrum?

a. exposure time

b. filtration

c. tube current

d. tube voltage

e. voltage waveform

B

In general, when changes are made that affect the x-ray emission spectrum and the:

a.) Amplitude increases, the radiation quantity decreases.

b.) Line spectrum moves, voltage waveform has changed.

c.) Spectrum shifts to the left, a higher quality beam is emitted.

d.) Spectrum shifts to the left, more filtration was used.

e.) Spectrum shifts to the right, a more penetrating beam is emitted.

E

How would the bremsstrahlung spectrum change if operation at 80 kVp/200 mA/100ms were changed to 64 kVp/200 mA/100 ms?

a.) It would remain the same, but the amplitude would decrease.

b.) It would remain the same, but the amplitude would increase.

c.) It would shift to the left, and the amplitude would be lower.

d.) It would shift to the left, and the amplitude would be higher.

e.) It would shift to the right, and the amplitude would be higher.

C

How would the characteristic spectrum change if operation were at 64 kVp/200 mA/20 ms? The characteristic x-ray spectrum would:

a.) Decrease in height.

b.) Disappear.

c.) Increase in height.

d.) Shift slightly to the left.

e.) Shift slightly to the right.

B