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WorksheetsRad Science Unit II 1075
Total questions: 48
Worksheet time: 24mins
The primary purpose of the step-down transformer is to
decrease the voltage going to the filaments
decrease the amperage going to the filaments
increase the voltage going to the filaments
increase the amperage going to the filaments
The synchronous timer is the most widely used timer in today’s x-ray equipment.
True
False
The __ converts volts to kilovolts.
step-up transformer
step-down transformer
autotransformer
none of these
A general purpose radiographic tube typically has __ filament(s).
one
two
three
four
The selection of the large or small filament in the cathode depends on the choice of focal spot size at the operating console and the
exposure time selected
kVp selected
mA station selected
none of these
Which of the following opens a circuit to keep the circuit and devices safe?
Fuse
Resistor
Circuit breaker
Conductor
Four rectifiers will produce
alternating current
half-wave rectified current
full-wave rectified current
indirect current
The filaments within the x-ray tube are found on the
primary circuit
secondary circuit
filament circuit
none of these
The only adjustable transformer in the x-ray circuit is the
primary side of the high voltage transformer
secondary side of the high-voltage transformer
autotransformer
step-down transformer
The step-down transformer is found on the
primary circuit
secondary circuit
filament circuit
none of these
Which of the following occurs first in the sequence of events leading to x-ray production?
AC is converted to DC.
Voltage becomes kilovoltage.
Anode and cathode become positively and negatively charged.
Electrons flow from cathode to anode.
AEC stands for
automatic x-ray control
applied exposure control
automatic exposure control
automatic exposure centering
During a radiographic procedure using AEC, the exposure time will be shorter when the spine covers the ionization chamber, as compared with air covering the chamber.
True
False
AEC controls the __ of radiation reaching the image receptor.
type
quantity
energy level
all of these
Determining which filament will be used during an exposure is done at the operating console by the selection of
small or large focal spot
small or large filament
high or low exposure time
high or low kVp
The device that adjusts the incoming power supplied to the x-ray circuit to maintain 220 V is the
circuit breaker
autotransformer
timer circuit
line compensator
The purpose of the filament circuit is to
produce high voltage
provide direct current to the x-ray tube
boil electrons off the filament
reduce the current reaching the filament
To produce x-rays, a cloud of electrons are necessary and the cathode must have a strong positive charge.
True
False
Three-phase power has less than 1% ripple.
True
False
Three-phase power
A. uses three AC waveforms at the same time
B. results in three times the ripple
C. is half-wave rectified
A and B
The least amount of ripple is the result of
half-wave rectification
full-wave rectification
three-phase power
high-frequency generators
The x-ray tube (aside from the filaments) is found on the
low voltage portion of the main circuit
high voltage portion of the main circuit
filament circuit
none of these
For modern AEC, the ionization chamber is placed between the __ and __.
tube; patient
patient; image receptor
grid; image receptor
image receptor; wall
Single-phase full-wave rectified current has
10% ripple
25% ripple
50% ripple
100% ripple
The timer that is based on a motor is the
synchronous timer
mAs timer
digital timer
electronic timer
Adjusting the rheostat (aka mA meter) changes the __ in the __ circuit.
resistance; primary
voltage; primary
resistance; filament
voltage; filament
The less the ripple
the more consistent the energy of the x-rays produced
the less consistent the energy of the x-rays produced
the greater the amount of radiation needed for a specific exposure
none of these
Ripple refers to
the fluctuation in amperage in the electricity
the fluctuation in voltage in the electricity
the fluctuation in resistance in the electricity
all of these
Half-wave rectification
suppresses half of the AC cycle
uses one to two rectifiers
is seldom used in modern x-ray equipment
all of these
A radiographic table should be
radiolucent
low atomic number
easily cleaned
all of these
The space charge effect describes
how the space charge is created
the effect the cloud of electrons has on the voltage across the tube
the effect the cloud of electrons has on limiting additional electrons being emitted
the effect of the heat of the filament on the size of the space charge
The oil surrounding the x-ray tube serves only to provide electrical insulation.
True
False
The protective tube housing is lined with
aluminum
copper
lead
glass
The relationship between the actual focal spot size, effective focal spot size, and anode target angle is called
the anode heel effect
the line-focus principle
Roentgen’s principle
all of these
Based on the anode heel effect, an image taken at 40 inches source-to-image receptor distance (SID) may demonstrate
decreased exposure toward the anode end of the beam
decreased exposure toward the cathode end of the beam
decreased exposure toward the left side of the beam
decreased exposure toward the right side of the beam
The motor that turns the anode operates through
the use of a transformer
the physical connection between rotor and stator
self-induction
mutual induction
The advantage to using a larger actual focal spot is
the image is sharper
there is less wear and tear on the tube
the image is less sharp
higher exposures can be used
The portion of the induction motor that is outside the tube enclosure is the
rotor
stator
disc
bearings
To keep the electrons together, the focusing cup
has a negative charge
has a positive charge
With a rotating anode, the focal spot becomes a focal
path
stripe
track
circle
How many heat units are produced with five consecutive exposures using a three-phase, 12-pulse x-ray unit; 85 kVp; and 20 mAs?
1,700 HU
2,295 HU
2,397 HU
11,985 HU
The tube rating chart plots mA, kVp, and
amperage
voltage
exposure time
resistance
The rotor is supplied with electric current through the x-ray circuit.
True
False
There is about 1–2% of __ added to the filament to increase thermionic emission.
thorium
rhenium
tungsten
copper
Pitting of the anode is the result of
very long exposure times
high exposures
failure to warm up the tube
all of the above
The area of the envelope where x-rays should exit the tube is the
target door
target window
x-ray trap
x-ray gate
Which of the following practices extend tube life?
Warm up the tube as appropriate.
Press the prep and exposure switches at almost the same time.
Avoid using very high exposures or long exposure times.
any of these
According to the 15% rule, to maintain exposure at the image receptor you can increase your ________ by 15% while halving your __________.
mAs; kVp
kVp; mAs
time; mAs
kVp; filament size
