Chapter 8 HW questions

When characteristic x-rays are produced, the energy of the x-rays is characteristic of: A) The mass of filtration B) The automatic number of the target C) The automatic number of the filter D) The orientation of the target E) The outer-shell electron binding energy

B) The automatic number of the target

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

Highest energy bremsstrahlung x-ray

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

When a tungsten-targeted x-ray tube is operated at 68 kVp: A) Some projectile electrons may have 75 keV of energy B) Some projectile electrons may have 68 keV of energy C) L-shell x-rays cannot be produced D) K-shell characteristic x-rays can be produced E) One possible K-shell characteristic x-ray will have 12 keV of energy

B) Some projectile electrons may have 68 keV of energy

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

The target material affects the amplitude of bremsstrahlung x-rays

The continuous x-ray emission spectrum principally depends on which of the following? A) mAs B) Projectile electron energy C) Target material D) Filtration E) Exposure time

B) Projectile electron energy

All will change the x-ray emission spectrum except: A) Adding filtration B) Reducing SID C) Reducing mA D) Increasing kVp

B) Reducing SID

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: 14 keV M-shell: 3 keV N-shell: 1 keV Which of the following characteristic x-rays would be produced with operation at 90 kVp?

67 keV The difference between the K and the L shell

If an N shell electron fills a K shell vacancy, what is the energy of the photon produced?

68.9

Where is the discrete line placed on an x-ray emission spectrum for a tungsten target?

69 keV The maximum energy of K characteristic in tungsten target is 69.5 keV

based on the illustration, what was the kVp selected?

95 This graph shows the selected kVp to be about 95, as the end of the line reaches to 95 on the x-axis.

Which of the curves have equal minimum wavelength and equal maximum energy ?

A and C

Of the three curves represented:

A and C were produced at the same kVp

Molybdenum has a lower atomic # than tungsten; therefore, the molybdenum x-ray emission spectrum: A) Has a lower amplitude B) Has a higher amplitude C) Has higher energy characteristic x-rays D) Extends to lower energies E) Extends to higher energies

A) Has a lower amplitude

The x-ray emission spectrum represents: A) X-rays emitted from the x-ray tube B) Total x-ray beam filtration C) Projectile electron energy D) Electron binding energy of target material E) Atomic mass and number of target atom

A) X-rays emitted from the x-ray tube

Bremsstrahlung x-rays are produced only at: A. Energies up to projectile electron energy. B. Projectile electron kinetic energy. C. Energies below characteristic x-rays. D. Discrete energies. E. Energies above characteristic x-rays.

A. Energies up to projectile electron energy.

Which of the following electron transitions results in the most useful bremsstrahlung x-ray A. None of those listed B. L to K C. M to K D. O to K E. M to L

A. None of those listed

The wavelength of an x-ray: A.) Becomes longer as projectile electron kinetic energy is reduced. D.) 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 as projectile electron kinetic energy is reduced.

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.

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

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 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.

Indicate which of the following figures represents an x-ray emission spectrum:

B

Of the three spectra:

B is more penetrating than C

Useful characteristic x-rays are produced in tungsten: A) By excitation of a K-shell electron B) By removal of a K-shell electron C) By ionization of an L-shell electron D) When the projectile electron interacts with an outer shell electron E) When a valence electron is removed.

B) By removal of a K-shell electron

The amplitude of the bremsstrahlung x-ray emission spectrum: A) Approaches maximum at an energy equal to the kVp B) Has maximum value at energy approximately one third the kVp C) Have maximum vale at energy equal to the kVp D) Approaches maximum at zero energy E) Is enhanced by filtration

B) Has maximum value at energy approximately one third the kVp

The efficiency of x-ray production is: A) Greater than that of heat production B) Independent of tube current C) In excess of 5% D) Independent of tube voltage E) Approximately 5%

B) Independent of tube current

If mass is expressed in kilograms and velocity in meters per second, kinetic energy will be expressed in: A) Electron volts B) Joules C) Newtons D) Ergs E) Coulombs

B) Joules

A diagnostic x-ray beam contains: A) Bremsstrahlung only B) Mostly Bremsstrahlung x-rays, with some characteristic x-ray C) Mostly compton x-rays, few Bremsstrahlung x-rays, and some pair production x-rays D) Some photoelectric x-rays E) Some compton x-rays, some Bremsstrahlung x-rays, and no pair production x-rays

B) Mostly Bremsstrahlung x-rays, with some characteristic x-ray

If filling a K shell vacancy, which shell electron would produce the highest-energy characteristic x-ray photon? A) N shell B) O shell C) M shell D) L shell

B) O shell The further the electron filling the vacancy is from the nucleus, the lower its binding energy, which means more energy will be given up to fill the vacancy, creating the strongest photon.

The area under the curve of the x-ray emission spectrum represents: A) The average energy of the x-rays B) The total number of x-rays C) The average number of x-rays per unit energy D) Total exposure (mGya) E) The total energy of the x-rays

B) The total number of x-rays

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.

An increase in mAs results in an increase in:

Both characteristic and bremsstrahlung x-rays

What type of radiation is graphed in this emission spectrum?

Bremsstrahlung

If a projectile electron enters an atom with 70 keV of energy, passes the nucleus, and leaves with 10 keV, what is produced? A) 70 keV brems x-ray B) 80 keV brems x-ray C) 60 keV brems x-ray D) Heat only

C) 60 keV brems x-ray To find the energy of the brems x-ray photon, the exit energy is subtracted from the entering energy.

Which of the following factors explains the low number of x-rays emitted at low energy? A) The glass envelop of the x-ray tube B) The mAs enclosing the x-ray tube C) Added filtration D) The product fo the tube current and exposure time E) The kVp

C) Added filtration

The shift of the characteristic x-ray spectrum to higher energy occurs because of which of the following? A) A decrease in kVp B) A higher atomic number filter C) An increase in target atomic number D) A decrease in voltage ripple E) An increase in kVp

C) An increase in target atomic number

Both the shape and the position of the characteristic x-ray emission spectrum: A) Represent projectile electron energy B) Result from nuclear interaction C) Correspond to target electron binding energies D) Are described by the number of projectile electrons E) Can be described as continuous

C) Correspond to target electron binding energies

All of these interactions may happen to projectile electrons when they encounter target atoms except: A) Produce characteristic x-rays B) Create heat energy C) Disintegrate upon impact D) Produce bremsstrahlung x-rays

C) Disintegrate upon impact Depending on the kinetic energy of the projectile electrons, they will either create heat energy, characteristic x-rays, or bremsstrahlung x-rays. After a target interaction, a projectile or filament electron may fill a vacancy in an atom or continue on as part of the current through the x-ray tube.

What is produced when the projectile electron excites an outer shell electron? A) Energy B) Photoelectric x-ray C) Heat D) Bremsstrahlung x-ray E) Characteristic x-ray

C) Heat

Which would increase the amplitude of the x-ray emission spectrum? A) Increase is added filtration B) Decrease in kVp C) Increase in mA D) Decrease in target material atomic number

C) Increase in mA

As the distance between the projectile electron and nucleus gets smaller, what happens to the brems x-ray photon energy? A) Decreases B) Stays the same C) Increases

C) Increases The closer the projectile electron passes to the nucleus, the stronger the attractive force and the stronger the resultant brems x-ray photon.

The kinetic energy of the projectile electron in an x-ray tube: A) Is converted to mass B) Is totally converted to x-ray energy C) Is about 1% efficient in the production of x-rays D) Causes ionization in the vacuum of the x-ray tube E) Causes excitation in the vacuum of the x-ray tube

C) Is about 1% efficient in the production of x-rays

The energy of a projectile can be measured in: A) Amperes B) Coulombs C) Joules D) Newtons E) Rads

C) Joules

L x-rays originate from which of the following shells being filled? A) N B) M C) L D) K

C) L The characteristic x-ray is named for the shell being filled.

X-rays are produced when: A) Projectile electrons bounce off the cathode. B) Electric current flows through the x-ray tube filament C) Projectile electrons interact with target atoms. D) The target angle is sufficiently large. E) The x-ray tube filament is heated to thermionic emission.

C) Projectile electrons interact with target atoms.

Based on the illustration, what factor has changed? A) mA B) mAs C) kVp D) Added filtration

C) kVp

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

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.

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.) Removal of nucleus. E.) Removal of outer-shell electron.

C.) Removal of inner-shell electron.

Which type of generator will create an x-ray emission spectrum with the highest amplitude?

High-frequency

What type of emission spectrum is represented in the figure below?

Characteristic x-ray emission

If an N shell electron fills an M shell vacancy, what is the energy of the photon produced? A) 1.69 B) 3.42 C) 4.7 D) 2.22

D) 2.22 To find the energy of a characteristic photon, the outer shell binding energy is subtracted from the inner shell binding energy of the shells involved.

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 fills the vacancy in the L-shell, the characteristic x-ray produced will have energy of: A) 4 keV B) 25 keV C) 22keV D) 26 keV E) 1 keV

D) 26 keV

Which of the following factors principally accounts for the reduced x-ray intensity at low energy? A) Beam collimation B) Voltage waveform C) Atomic number of the target material D) Added filtration E) Energy spectrum of the projectile electrons

D) Added filtration

Normally, the x-ray emission spectrum contains: A) Only characteristic x-ray s B) Only Bremsstrahlung x-rays C) Both photoelectric and compton x-rays D) Both characteristic and Bremsstrahlung x-rays E) Only discrete lines

D) Both characteristic and bremsstrahlung x-rays

To construct an x-ray emission spectrum, one must know the: A) mAs and x-ray frequency B) kVp and mAs C) Projectile electron number and energy interval D) Number of x-rays at each energy interval E) Target element and filtration

D) Number of x-rays at each energy interval

What factor change is evident in the x-ray emission spectrums below? A) Focal spot size B) Voltage waveform (generator type) C) Added filtration D) Target material

D) Target material The emission spectrums represent changes in the target material as evidenced by the changes in amplitude and characteristic peak on the graph

If an x-ray emission spectrum represented operation at 85 kVp with a tungsten target: A) X-rays representing maximum frequency would occur at 69 keV B) X-rays representing minimum wavelength would occur at 0 keV C) At 85 keV, the number of projectile electrons would be maximum D) The K-characteristic x-ray emission would occur at 69 keV E) Bremsstrahlung x-rays would be the most intense at 85 keV

D) The K-characteristic x-ray emission would occur at 69 keV

If an x-ray emission spectrum represented operation at 26 kVp with a molybdenum target: A) K-characteristic x-rays would not be produced B) maximum frequency x-rays would have an energy of 17 keV C) More characteristic radiation would be emitted D) The characteristic radiation would have an energy approximately 19 keV E) Minimum wavelength x-rays would have an energy of 20 keV

D) The characteristic radiation would have an energy approximately 19 keV

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.

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.

As the distance between the projectile electron and nucleus increases, what happens to the brems x-ray photon energy?

Decreases

How would the characteristic spectrum change if operation at 80 kVp 200 mA 100 ms were changed to at 64 kVp 200 mA 20 ms ? The characteristic x-ray spectrum would:

Disappear

Characteristic x-rays: A) Are characteristic of the filter material B) Are characteristic of the voltage waveform C) Vary in energy as kVp is varied D) Have velocity varying from zero to the speed of light E) Are characteristic if target Z

E) Are characteristic if target Z

The energy of characteristic x-ray increases with increasing: A) Atomic mass of target material B) kVp C) Filtration D) Voltage waveform E) Atomic number of target material

E) Atomic number of target material

Characteristic x-radiation is related to the: A) Number of K-shell electrons B) Difference between K and L shell binding energy C) Number of electrons D) Energy to eject L shell electrons E) Energy required to eject K shell electrons

E) Energy required to eject K shell electrons

The characteristic x-ray emission spectrum principally depends on which of the following? A) mAs B) Projectile electron energy C) kVp D) Filtration E) Target material

E) Target material

The x-ray emission spectrum is a plot of: A) X-rays and electrons emitted from target atoms B) mAs versus kVp C) The number of electrons versus energy D) X-ray and electrons emitted from cathode atoms E) The number of x-rays versus energy

E) The number of x-rays versus energy

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.

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

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.

In the diagnostic range, characteristic radiation constitutes most of the x-ray beam. True/ false?

False

During the production of characteristic radiation, only L shell electrons can fill K shell vacancies. True/False?

False. Any shell can fill the vacancy, the closest one is most likely.

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

Filtration

This graph shows the emission spectrum from several target materials. which line color represents the material with the highest atomic number?

Gold

The wavelength of an x-ray is:

Inversely proportional to its energy

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

It would shift to the left, and the amplitude would be lower

K x-rays originate from which of the following shells being filled?

K

In the emission spectrum below, number 4 labels the:

K x-rays

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

Maximum projectile electron energy

What is labeled as number 1 in this emission spectrum graph?

Number of x-rays

What is the source of energy that results in characteristic photons?

Potential energy of the electron filling the vacancy

An increase in kVp results in an increase in:

Radiation quality

How would the total emission spectrum be affected if the x-ray techniques changed from 80 kVp and 80 mAs to 80 kVp, 400 mA, 100 ms? The relative position of the spectrum would:

Remain the same, but the amplitude would decrease

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

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

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

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

The area under the emission spectrum

Minimum wavelength is related to:

The kinetic energy of the projectile electron

Most of the energy produced during the production of x-rays is heat. True/ False?

True

Characteristic x-rays are produced with the filling of each shell vacancy in the tungsten atom. True/ False?

True The cascading of outer shell electrons filling the inner shell vacancies results in each orbital electron giving up excess potential energy as a characteristic x-ray photon.

In the diagnostic range, bremsstrahlung radiation constitutes most of the x-ray beam. True/ False?

True. Because projectile electrons striking orbital electrons occurs mostly by chance, most of the beam is composed of brems x-rays.

According to this table:

Tungsten obviously has a greater number of electrons than molybdenum.

Which characteristic is reduced as x-ray energy increases?

X-ray wavelength

What type of emission spectrum is represented in the graph below?

bremsstrahlung x-ray emission

What is the energy of the majority of photons in this illustration?

about 30

The majority of the x-ray emission spectrum represents:

brems photons

The joules (J) of energy generated by electron-target interactions is given by:

kV x mA x s

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

kVp

The output intensity of an x-ray tube: А. Is primarily due to bremsstrahlung x-rays В. Increases when filtered С. Is limited by the K-shell binding energy D. Often is measured in curies (Becquerels) E. Is monoenergetic

А. Is primarily due to bremsstrahlung x-rays