Chapter 03: Radiation Characteristics
Iannucci: Dental Radiography, 5th Edition
MULTIPLE CHOICE
1. In dental radiography, the term ________ is used to describe the mean energy or penetrating
ability of the x-ray beam.
a.
quality
b.
quantity
c.
intensity
d.
wavelength
2. Which of the following statements is true of wavelength in reference to radiation?
a.
X-rays with shorter wavelength have less penetrating power.
b.
X-rays with longer wavelength have less penetrating power.
c.
X-rays with longer wavelength are less likely to be absorbed by matter.
d.
Milliamperage controls the wavelength and energy of the x-ray beam.
3. ______________ is a measurement of force that refers to the potential difference between two
electrical charges.
a.
Exposure time
b.
Wavelength
c.
Voltage
d.
Ampere
4. When the kilovoltage is increased
a.
electrons move from the anode to the cathode with more speed.
b.
photons move from the anode to the cathode with more speed.
c.
electrons move from the cathode to the anode with more speed.
d.
photons move from the cathode to the anode with more speed.
5. Which of the following statements is true of the use of voltage in dental x-ray equipment?
a.
Dental x-ray equipment requires the use of 3 to 5 volts.
b.
Dental x-ray equipment requires the use of less than 60 kilovolts.
c.
Dental x-ray equipment uses more than 70 kilovolts.
d.
Dental x-ray equipment requires the use of 60 to 70 kilovolts.
6. When contrasted with the use of 70 kV for dental x-rays, the use of 60 kV produces
a.
more penetrating dental x-rays with longer wavelength.
b.
less penetrating dental x-rays with longer wavelength.
c.
more penetrating dental x-rays with shorter wavelength.
d.
less penetrating dental x-rays with shorter wavelength.
7. The kVp represents
a.
the mean x-ray tube voltage.
b.
the mean filament voltage.
c.
the maximum or peak voltage of an alternating current.
d.
the maximum or peak voltage of a direct current.
8. When kilovolt is increased, a
a.
lower energy x-ray beam with increased penetrating ability results.
b.
lower energy x-ray beam with decreased penetrating ability results.
c.
higher energy x-ray beam with increased penetrating ability results.
d.
higher energy x-ray beam with decreased penetrating ability results.
9. (1) Density is the overall darkness or blackness of a dental image. (2) When the kilovoltage is
increased while other exposure factors remain constant, the resultant image exhibits a
decreased density and appears lighter.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
10. When lower kilovoltage settings are used, an image with ____ will result.
a.
high contrast
b.
low contrast
c.
many shades of gray
d.
there is no change in contrast
11. An image with “low” contrast
a.
is useful for the detection of periodontal or periapical disease and has many shades
of gray.
b.
is useful for the detection and progression of dental caries and has many shades of
gray.
c.
is useful for the detection of periodontal or periapical disease and has many black
and white areas.
d.
is useful for the detection and progression of dental caries and has many black and
white areas.
12. Exposure time is measured in
a.
kV.
b.
milliamperage.
c.
density.
d.
impulses.
13. The quantity of the x-rays produced is controlled by
a.
voltage.
b.
kilovoltage.
c.
kilovoltage peak.
d.
milliamperage.
14. Milliamperage regulates the _________ of electrons produced at the cathode filament.
a.
quality
b.
quantity
c.
speed
d.
power
15. In regard to increasing density
a.
an increase in either kV or mA will increase density.
b.
an increase in kV will increase density, but an increase in mA will not increase
density.
c.
an increase in mA will increase density, but an increase in kV will not increase
density.
d.
neither an increase in kV nor an increase in mA will increase density.
16. Which of the following changes will increase x-ray beam intensity?
a.
Decreasing the kilovoltage
b.
Decreasing the milliamperage
c.
Decreasing the exposure time
d.
Decreasing the source-to-film distance
17. According to the inverse square law, the intensity of radiation is __________ proportional to
the ______________ from the source of radiation.
a.
directly; distance
b.
directly; square of the distance
c.
inversely; distance
d.
inversely; square of the distance
18. According to the inverse square law, if the length of the PID is halved, the resultant beam is
___________ as intense.
a.
four times
b.
twice
c.
half
d.
one quarter
19. Aluminum filters are used to remove _______-energy, ________ wavelength x-rays.
a.
low; longer
b.
high; longer
c.
low; shorter
d.
high; shorter
20. Aluminum filters
a.
remove more penetrating x-rays from the beam.
b.
decrease the mean penetrating ability of the x-ray beam.
c.
remove high-energy x-rays from the beam.
d.
reduce the intensity of the x-ray beam.
21. You have been using a dental x-ray machine that has a 4-inch PID. Your new machine has an
8-inch PID. Given that all exposure factors remain the same, according to the inverse square
law, the resultant beam would be ___________ as intense.
a.
four times
b.
twice
c.
half
d.
one quarter
22. (1) As kilovoltage, milliamperage, and time increase, x-ray beam intensity decreases. (2) As
distance and filtration increase, the intensity of the x-ray beam increases.
a.
Both statements are true.
b.
Both statements are false.
c.
The first statement is true; the second statement is false.
d.
The first statement is false; the second statement is true.
23. You have taken your first dental image on your patient. The contrast is high and you are
looking for periodontal disease. You are using a DC machine and you have control of your
settings. You have a 60- to 70-kV range and a 6- to 8-mA range. You had the kV set at 60, the
mA set at 7, and the impulses set at 6/100. While leaving all other settings the same, which
setting would you adjust to create better contrast for detecting periodontal disease?
a.
Increase kV to 70.
b.
Increase mA to 8.
c.
Decrease mA to 6.
d.
Increase time to 7/100.
24. You are going to take dental images on your patient. He is larger than average. What machine
setting adjustment should you make prior to taking dental images?
a.
Increase kV.
b.
Increase mA.
c.
Increase impulses.
d.
You don’t need to make any adjustments.