Ch. 2: Radiation Physics

D) K-shell

Which electrons have the greatest binding energy?

A) N-shell

B) M-shell

C) L-shell

D) K-shell

B) negative

What type of electrical charge does the electron carry?

A) positive

B) negative

C) no charge

D) positive or negative

C) molecule

Which term describes two or more atoms that are joined by chemical bonds?

A) ion

B) ion pair

C) molecule

D) proton

B) atom that loses an electron

What statement describes ionization?

A) atom without a nucleus

B) atom that loses an electron

C) atom with equal numbers of protons and electrons

D) none of the above

B) radioactivity

Which term describes the process by which unstable atoms undergo spontaneous disintegration in an effort to attain a more balanced nuclear state?

A) radiation

B) radioactivity

C) ionization

D) ionizing radiation

D) nucleons

Which is not a type of particulate radiation?

A) alpha particles

B) beta particles

C) protons

D) nucleons

A) electrons

Which is not a type of electromagnetic radiation?

A) electrons

B) radar waves

C) microwaves

D) x-rays

B) Wavelength is the distance between waves

What statement is incorrect?

A) Velocity is the speed of a wave

B) Wavelength is the distance between waves

C) Frequency is the number of wavelengths that pass a given point in a certain amount of time

D) Frequency and wavelength are inversely related

A) X-rays travel at the speed of sound

What statement is incorrect?

A) X-rays travel at the speed of sound

B) X-rays have no charge

C) X-rays cannot be focused to a point

D) X-rays cause ionization

B) X-rays have more energy than does visible light

What statement is correct?

A) X-rays are a form of electromagnetic radiation; visible light is not

B) X-rays have more energy than does visible light

C) X-rays have a longer wavelength that does visible light

D) X-rays travel more slowly that does visible light

Electronic focusing cup

Label 11

Cathode (-)

Label 12

Filament and electron cloud

Label 13

Focal spot on tungsten target

Label 14

Anode (+)

Label 15

Vaccum

Label 16

Useful x-ray beam

Label 17

Glass envelope

Label 18

Copper stem

Label 19

Tube window

Label 20

Aluminum disks

Label 21

Lead collimator

Label 22

Position-indicating device

Label 23

Tubehead seal

Label 24

X-ray tube

Label 25

Insulating oil

Label 26

Unleaded glass window of x-ray tube

Label 27

Metal housing of x-ray tubehead

Label 28

B) low-voltage circuit

Which regulates the flow of electrical current to the filament of the x-ray tube?

A) high-voltage circuit

B) low-voltage circuit

C) high-voltage transformer

D) low-voltage transformer

A) step-up transformer

Which is used to increase the voltage in the high-voltage circuit?

A) step-up transformer

B) step-down transformer

C) autotransformer

D) step-up circuit

C) X-rays travel from the filament to the target

Which does not occur when the high-voltage circuit is activated?

A) The unit produces an audible and visible signal

B) Electrons produced at the cathode are accelerated across the tube to the anode

C) X-rays travel from the filament to the target

D) Heat is produced

B) positive anode

Which is the location where x-ray are produced?

A) positive cathode

B) positive anode

C) negative cathode

D) negative anode

C) negative cathode

Which is the location where thermionic emission occurs?

A) positive cathode

B) positive anode

C) negative cathode

D) negative anode

A) general radiation

Which accounts for 70% of all the x-ray energy produced at the anode?

A) general radiation

B) characteristic radiation

C) Compton scatter

D) coherent scatter

B) characteristic radiation

Which occurs only at 70 kV or higher and accounts for a very small part of the x-rays produced in the dental x-ray machine?

A) general radiation

B) characteristic radiation

C) Compton scatter

D) coherent scatter

A) radiation that exits the tubehead

Which describes primary radiation?

A) radiation that exits the tubehead

B) radiation that is created when x-rays come in contact with matter

C) radiation that has been deflected from its path by the interaction with matter

D)none of the above

C) radiation that has been deflected from its path by the interaction with matter

Which describes scatter radiation?

A) radiation that exits the tubehead

B) radiation that is created when x-rays come in contact with matter

C) radiation that has been deflected from its path by the interaction with matter

D)none of the above

A) Compton

Which type of scatter occurs most often with dental x-rays?

A) Compton

B) coherent

C) photoelectric

D) none of the above

Absorption

Identify the x-radiation interaction with matter

Compton scatter

Identify the x-radiation interaction with matter

Coherent scatter

Identify the x-radiation interaction with matter

No interaction

Identify the x-radiation interaction with matter

B) no scatter; ionization

The interaction of x-radiation with matter illustrated in Figure 2-29 demonstrates:

A) no scatter; no ionization

B) no scatter; ionization

C) scatter; no ionization

D) scatter; ionization

D) scatter; ionization

The interaction of x-radiation with matter illustrated in Figure 2-30 demonstrates:

A) no scatter; no ionization

B) no scatter; ionization

C) scatter; no ionization

D) scatter; ionization

C) scatter; no ionization

The interaction of x-radiation with matter illustrated in Figure 2-31 demonstrates:

A) no scatter; no ionization

B) no scatter; ionization

C) scatter; no ionization

D) scatter; ionization

A) no scatter; no ionization

*NO INTERACTION = RADIOGRAPHY*

The interaction of x-radiation with matter illustrated in Figure 2-32 demonstrates:

A) no scatter; no ionization

B) no scatter; ionization

C) scatter; no ionization

D) scatter; ionization

D

Which has the shortest wavelength?

A

Which has the longest wavelength?

A

Which has the lowest frequency?

D

*Frequency and wavelength are inversely related; if the frequency of the wave is high, the wavelength will be short, and if the frequency is low, the wavelength will be long*

Which has the highest frequency?

wavelength

the distance between the crest of one wave and the crest of the next

Radioactivty

the process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state

Frequency

The number of wavelengths that pass a given point in a certain amount of time

Secondary Radiation

This type of radiation is created when the primary beam interacts with matter

Velocity

this term refers to the speed of the wave

Nucleus

the dense core of the atom; composed of protons and neutrons

Ionizing

radiation capable of producing ions by removing or adding an electron to an atom

electromagnetic radiation

examples include cosmic rays, gamma rays, x-rays, ultraviolet rays, visible light, infrared light radar waves, microwaves, and radio waves

Primary Radiation

this type of radiation refers to the penetrating x-ray beam that is produced at the target of the anode and that exits the tubehead

Electrons

tiny, negatively charged particles that have very little mass

Particulate Radiation

type of radiation composed of tiny particles of matter that possess mass and travel in straight lines at high speeds

Scatter Radiation

this type of radiation is the result of an x-ray that has been deflected from its path

orbits or shells

a well-defined path

Control Panel

Identify A

Extension Arm

Identify B

Tubehead

Identify C

Tubehead

Identify 1

Position-indicating device

Identify 2

When the filament circuit is activated, the filament heats up, and thermionic emission occurs

Describe the production of x-rays in the x-ray tube illustrated in Fig. 2-5

A

When the exposure button is activated, the electrons are accelerated from the cathode to the anode

Describe the production of x-rays in the x-ray tube illustrated in Fig. 2-5

B

The electrons strike the tungsten target, and their kinetic energy is converted to x-rays and heat

Describe the production of x-rays in the x-ray tube illustrated in Fig. 2-5

C

Electrons travel from cathode to anode

CAT: ew cats = negative

NAP: yay! = positive

Describe how *"cat ---> nap"* can help you to remember the flow of the electrons in the x-ray tube.

invisible

*appearance*

X-rays are *visible / invisible*

no weight

*mass*

X-rays have *weight / no weight*

no charge

*charge*

X-rays have *no charge / + charge / - charge*

speed of light

*speed*

X-rays travel at the *speed of sound / speed of light*

short

hight

*wavelength*

X-rays have *long / short* wavelengths with a *high / low* frequency

can

*path of travel*

X-rays travel in straight lines and *can / cannot* be deflected

cannot

*focusing capability*

X-rays *can / cannot* be focused to a point

can

*penetrating power*

X-rays *can / cannot* penetrate liquids, solids, and gases

are

*absorption*

X-rays *are / are not* absorbed by matter

cause

*ionization*

X-rays *cause / do not cause* ionization

can

*fluorescence*

X-rays *can / cannot* cause certain substances to fluoresce; emit light

can

*effect on film*

X-rays *can / cannot* produce an image on photographic film

cause

*effect on tissues*

X-rays *cause / do not cause* biologic changes in living cells