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Worksheets2025 RHS TEST CH 38 1-8
Total questions: 99
Worksheet time: 50mins
Who is credited with the first practical use of radiographs in dentistry, in 1896.
C. Edmund Kells
Otto Walkoff
Wilhelm Roentgen
Energy is defined as
the capacity to do work.
anything that occupies space.
anything that has form or shape.
Matter is anything that
is alive and breathes oxygen.
that is important.
occupies space and has form or shape.
Dental x-rays cannot make atoms radioactive.
True
False
Electrons travel around the nucleus of an atom in well-defined paths known as
gravity
shells
solar systems
A minute (tiny) bundle of pure energy that has no weight or mass
photon
ion
proton
Which of the following describes ionization?
an atom without a nucleus
an atom that loses an electron
an atom with equal numbers of protons and electrons
X-rays are a form of energy that can ___________ matter.
penetrate
move
reflect
X-rays belong to a group called ______________ radiation.
electromagnetic
gamma
medical
Electromagnetic radiation is made up of photons that travel through space at the speed of __________.
light
sound
both a and b are correct
Electromagnetic radiation travels in a _________ line with a __________ motion.
straight, wavelike
slowly, serpentine
curved, back and forth
Which of the following is NOT a type of electromagnetic radiation?
electrons
radar waves
microwaves
x-rays
Short wavelengths can penetrate matter more easily than longer wavelengths.
True
False
Insulating oil surrounds the x-ray tube and prevents leakage by absorbing the photons created in the production of x-rays.
True
False
The x-ray tube is the __________ of the x-ray–generating unit.
brains
heart
sole
The aluminum filter is an __________ sheet _______ mm thick.
aluminum, 0.5
lead, 2.5
tungsten, 5
Which of the following regulates the flow of electrical current to the filament of the x-ray tube?
high-voltage circuit
low-voltage circuit
high-voltage transformer
low-voltage transformer
The focusing cup made of ______________.
nickel
tungsten
molybdenum
The purpose of the cathode is to supply the electrons necessary to generate x-rays.
True
False
The anode is composed of a _________ target that is embedded in the larger ___________ stem.
tungsten, copper
molybdenum, tungsten
tungsten, molybdenum
Which of the following is the location in which x-rays are produced?
positive cathode
positive anode
negative cathode
negative anode
Which of the following is the location in which thermionic emission occurs?
positive cathode
negative anode
negative cathode
The lead diaphragm determines the size and shape of the
Electron cloud
Film used
X-ray beam
Filament
The long (16-inch) PID is more effective in reducing exposure to the patient than a short (8-inch) PID because there is less divergence (separation) of the beam.
True
False
THE LENGTH OF THE PID IS CHANGED FROM 16 INCHES TO 8 INCHES. THE RESULTANT INTENSITY OF THE BEAM WILL BE:
four times as intense
twice as intense
half as intense
one-fourth as intense
THE PORTION OF THE TARGET THAT IS STRUCK BY ELECTRONS IS CALLED THE
Focal spot
Photon point
Principal point
End point
Used to decrease voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the filament circuit.
Step Up Transformer
Step Down Transformer
Low voltage circuit
Used to increase incoming voltage to 65,000 to 100,000 volts used by the high-voltage circuit.
Step Up Transformer
Step Down Transformer
Low voltage circuit
When electrons strike the tungsten target, less than ____ of the energy is converted to x-rays, the remaining _______ is lost as heat.
1%, 99%
99%, 1%
50%, 50%
Which of the following is used to increase the voltage in the high-voltage circuit?
step-up transformer
step-down transformer
autotransformer
step-up circuit
Which of the following accounts for 70% of all the x-ray energy produced at the anode?
general radiation
characteristic radiation
Compton scatter
coherent scatter
Which of the following describes primary radiation?
radiation that exits the tubehead
radiation that is created when x-rays come in contact with matter
radiation that has been deflected from its path by the interaction with matter
none of the above
Which of the following describes scatter radiation?
radiation that exits the tubehead
radiation that is more penetrating than primary radiation
radiation that has been deflected from its path by interaction with matter
none of the above
THE QUALITY OR PENETRATING POWER OF SECONDARY RADIATION IS
More than that of primary radiation
Less than that of primary radiation
The same as that of primary radiation
Unrelated to that of primary radiation
WHICH FACTORS INFLUENCE THE POTENTIAL DANGER OF IONIZING RADIATION?
Quantity of exposure
Duration of exposure
Type of tissue exposed
All of them
The portion of a processed radiograph that appears dark or black is termed:
dense
radiolucent
radiopaque
transparent
The portion of a processed radiograph that appears light or white is termed:
radiolucent
radiopaque
dense
high density
WHICH OF THE FOLLOWING MATERIALS IS MOST RESISTANT TO THE PENETRATION OF IONIZING RADIATION?
Aluminum
Copper
Lead
Plastic
Which of the following appears most radiolucent on a dental radiograph?
bone
enamel
dentin
air space
An example of a radiopaque structure seen on dental x-rays is:
bone
enamel
dentin
all of the above
SCATTER RADIATION IS A TYPE OF
Secondary radiation
Primary radiation
Stray radiation
Filtered radiation
IDENTIFY THE TERM THAT DESCRIBES HOW DARK AND LIGHT AREAS ARE DIFFERENTIATED ON A FILM:
contrast
density
intensity
polychromatic
A radiograph that has many light and dark areas with few shades of gray is said to have:
high density
low density
high contrast
low contrast
In dental radiography, the quality of the x-ray beam is controlled by:
kVp
mA
exposure time
source-to-film distance
The difference in the degrees of blackness between adjacent areas on a dental radiograph is termed:
density
contrast
subject thickness
diagnostic quality
Identify the kilovoltage range for most dental x-ray machines:
50-60 kV
60-70 kV
65-100 kV
>100 kV
A higher kilovoltage produces x-rays with:
greater energy levels
shorter wavelengths
more penetrating ability
all of the above
Radiation produced with high kilovoltage results in:
short wavelengths
long wavelengths
less penetrating radiation
lower energy levels
When viewed on a light source, a dental radiograph that demonstrates many shades of gray is said to have:
high contrast
low contrast
high density
low density
If kilovoltage is decreased with no other variations in exposure factors, the resultant film will:
appear lighter
appear darker
remain the same
either a or b
When viewed on a light source, a dental radiograph that demonstrates very dark areas and very light areas is said to have:
high contrast
low contrast
high density
low density
The one exposure factor that has a direct influence on the contrast of a dental radiograph is:
operating kilovoltage peak
milliamperage
exposure time
subject thickness
The type of contrast preferred in dental radiography is:
low contrast
long-scale contrast only
short-scale contrast only
a compromise between short-scale contrast and long-scale contrast
Identify the unit of measurement used to describe the amount of electric current flowing through the x-ray tube:
volt
ampere
kilovoltage peak
force
Increasing milliamperage alone results in a film with:
high contrast
low contrast
increased density
decreased density
The overall blackness or darkness of a dental radiograph is termed:
density
contrast
subject thickness
diagnostic quality
In dental radiography, the quantity of radiation produced is controlled by:
kVp
mA
exposure time
b and c
Increasing the operating kilovoltage peak (kVp) will cause:
an increase in density; the film appears darker
an increase in density; the film appears lighter
a decrease in density; the film appears darker
a decrease in density; the film appears lighter
Increasing milliamperage results in an increase in:
temperature of the filament
mean energy of the beam
number of x-rays produced
a and c
Identify the milliamperage range for dental radiography:
1-5 mA
4-10 mA
7-15 mA
>15 mA
Increasing the exposure time will cause:
an increase in density; the film appears darker
an increase in density; the film appears lighter
a decrease in density; the film appears darker
a decrease in density; the film appears lighter
Increasing which of the following exposure controls will increase the intensity of the x-ray beam? (1) kilovoltage, (2) milliamperage, (3) exposure time, (4) source-to-film distance
1 and 2
2 and 3
1, 2, and 3
All of the above
WHICH OF THE FOLLOWING FACTORS MOST AFFECTS THE PENETRATING POWER OF AN X-RAY?
Exposure time
b. Kilovoltage (kVp)
c. Milliamperage (mA)
d. Length of PID (cone)
A dental patient has thick, soft tissues and dense bones. To compensate for this increase in subject thickness and provide a film of diagnostic density, the dental radiographer may:
increase the exposure time
increase the milliamperage
increase the operating kilovoltage peak
any of the above
WHEN TAKING A PANORAMIC RADIOGRAPH OF AN OBESE PATIENT, AS COMPARED TO A SLIM PATIENT, EXPOSURE (KVP OR MA) SHOULD
Be decreased
Be increased
Remain the same
DENSITY OF A RADIOGRAPH IS CONTROLLED BY ALL OF THE FOLLOWING EXCEPT
kVp (kilovoltage potential)
TFD (target film distance)
OFD (object film distance)
mA (milliamperage)
MILLIAMPERAGE CONTROLS
The speed with which electrons move from cathode to anode
Cooling of the anode
Heating of the anode
Heating of the cathode
The unsharpness, or blurred edges, seen on a radiographic image is termed:
distortion
umbra
penumbra
contrast
The capability of the x-ray film to reproduce distinct outlines of an object is termed:
sharpness
magnification
distortion
diagnostic quality
FOR MAXIMUM PENETRATION OF X-RAYS, WHICH OF THE FOLLOWING COMBINATIONS WOULD YOU SELECT?
90 kVp and 10 mA
65 kVp and 10 mA
70 kVp and 90 mA
10 kVp and 65 mA
A variation in the true size and shape of the object being radiographed is termed:
magnification
distortion
sharpness
resolution
THE AVOIDANCE OF RADIOGRAPHIC DISTORTION OR MAGNIFICATION IS ESPECIALLY IMPORTANT IN ENDODONTIC TREATMENT BECAUSE:
The tooth may need to be extracted
b. The canal may be too narrow for instrumentation
c. A retake might have to be taken for accuracy
d. The length of the canal must be accurately measured
The geometric characteristic that refers to a radiographic image that appears larger than its actual size is termed:
distortion
detail
definition
magnification
THE BEST TYPE OF X-RAY TO PENETRATE BODY TISSUE IS
Low frequencies
Hard rays, short wavelength
Long wavelength
Soft rays, long wavelength
WHY IS AN INCREASED TARGET-FILM DISTANCE REQUIRED IN THE PARALLELING TECHNIQUE?
To avoid image magnification
To avoid distortion
To reduce scatter radiation
To improve film placement
AS THE TARGET –FILM DISTANCE IS INCREASED, THERE IS
More chance of overlapping
More chance of elongation
Less distortion
More chance of foreshortening
TO INCREASE THE PENETRATING QUALITY ON AN X-RAY BEAM, THE AUXILIARY MUST
Increase kVp
Decrease kVp
Increase mA
Increase FFD
Which of the following is most susceptible to ionizing radiation?
bone tissue
small lymphocyte
muscle tissue
nerve tissue
epithelial tissue
Which of the following is considered radioresistant?
immature reproductive cells
young bone cells
mature bone cells
epithelial cells
none of the above
Direct radiation injury occurs when:
x-ray photons hit critical targets within a cell
x-ray photons pass through the cell
x-ray photons are absorbed and form toxins
free radicals combine to form toxins
none of the above
Identify the correct statement.
Short-term effects are seen with small amounts of radiation absorbed in a short period.
Short-term effects are seen with small amounts of radiation absorbed in a long period.
Long-term effects are seen with small amounts of radiation absorbed in a short period.
Long-term effects are seen with small amounts of radiation absorbed in a long period.
none of the above
THE X-RAY AT THE CENTER OF THE PRIMARY BEAM IS CALLED THE
Photon
Central ray
Secondary ray
Restricted beam
The latent period in radiation biology is the period of time between:
exposure of film and development
subsequent doses of radiation
cell rest and cell mitosis
exposure to x-radiation and clinical symptoms
none of the above
Radiation injuries that are not seen in the person irradiated but occur in future generations are termed:
somatic effects
genetic effects
cumulative effects
short-term effects
long-term effects
FILTRATION OF THE X-RAY BEAM PROTECTS THE PATIENT BY
Eliminating all radiation from the x-ray head
Eliminating weak wavelength x-rays from the x-ray beam
Eliminating short wavelength x-rays from the x-ray beam
Decreasing exposure time
The traditional unit for measuring x-ray exposure in air is termed:
gray
coulombs per kilogram
rem
rad
roentgen
The unit for measuring the absorption of x-rays is termed:
roentgen
rad
rem
QF
Sievert
Which of the following is used only for x-rays?
sievert
gray
rem
rad
roentgen
Identify the average dose of background radiation received by an individual in the United States.
0-100 mrads (0-0.001 Gy)
50-100 mrads (0.0005-0.001 Gy)
150-300 mrads (0.0015-0.003 Gy)
200-500 mrads (0.002-0.005 Gy)
500-1000 mrads (0.005-0.01 Gy)
Identify the single largest contributor to artificial radiation exposure.
radioactive materials
medical radiation
consumer products
weapons production
nuclear fuel cycle
THE MOST SENSITIVE CELLS TO IONIZING RADIATION ARE
Bone cells
Muscle cells
Nerve cells
Reproductive cells
A DENTAL ASSISTANT MAY EXPOSE RADIOGRAPHS IF
The dentist gives permission
He or she is a certified dental assistant
It is permissible in the state in which he or she is employed
He or she is supervised by the dentist or hygienist
The amount of radiation exposure an individual receives varies depending on which of the following factors:
film speed
collimation
technique
exposure factors
all of the above
Which of the following factors contributes to radiation injury?
total dose
dose rate
cell sensitivity
age
all of the above
THE AMOUNT OF RADIATION A PERSON RECEIVES
Begins anew each day
Is cumulative only on the skin
Is cumulative in the entire body
Is not harmful in small doses
IF THE OPERATOR SUSPECTS A MALFUNCTION IN THE X-RAY EQUIPMENT, WHAT IS THE FIRST THING TO BE DONE?
Change mA and kVp settings
Call the state radiation inspector
Stop using the equipment
Call the repair service
WHICH OF THE FOLLOWING POSITION-INDICATING DEVICES IS MOST EFFECTIVE IN REDUCING PATIENT EXPOSURE?
conical PID
rectangular PID
round PID
All are equally effective in reducing patient exposure.
MAXIMUM PROTECTION OF THE PATIENT REQUIRES THAT THE X-RAY BEAM PASS THROUGH A
Shielded open-ended cone
Plastic closed-ended cone
Shielded closed-ended cone
Lead apron
WHICH OF THE FOLLOWING IS THE MAJOR CAUSE OF UNNECESSARY RADIATION TO DENTAL PATIENTS?
Use of metal PID’s
Faulty operator technique
Use of defective lead aprons
Use of excessive cone length
