week 4 Phycs.DX.IM Flashcards
a moving charged particle creates a
magnetic field
induced current is defined as
creating a relative movement between a conductor and a magnetic field
result of induced current
movement of e- in the conductor, creating an induced electromotive force or current
relative movement
comparing one object spatial relationship to another
if you generate e- what is produced?
current
static magnetic field means what?
it is a static/steady current
what happens to the magnetic field with an AC current with each voltage cycle?
it will expand and collapse
In induced velocity what has to move in order for the e- to move
magnetic field or the conductor
turns ratio will change
the voltage and amperage between the 2 circuits
induced current occurs in the
secondary coil
transformers operate on the principle of
induced current
Transformers use induced current principle to change
voltage and amperage of a circuit.
turns ratio
number of turns (circles of wire) around the primary coil vs. number of turns around in the secondary coil
voltage and amperage are_____ and _________ related across a transformer
- inversely
2. proportionately
as volts go up what happens to amperes?
amperes go down
transformer allow you to change
amperes and voltage
mechanical support of tube
tube stand
Location of tube is
inside
grid is what partion of xray?
what xray passes through
cassette of xray contains
film
collimator does what on the xray film
*
limits the size of the beam xraying a certain portion of body
x-rays first pass through
mirror
second stage of xray passes through what?
passes through the shutters
________ and a ______ are also part of the collimator to project a pattern of visible light accurately demonstrating the area which will be irradiated
- light source
2. mirror
central ray is defined as a ?
imaginary photon right in the middle of the xray beam
knife light tells us the what about the central ray?
level of the central ray
3 key exposure variables
time
tube current
tube potential
line compensation
correction of in out of voltage to machine
most xrays are taken between
60 - 100 kev
autotransformer is made of
one set of windings
high voltage transformers change
Volts –> kilovolts
x ray housing reduces
the spread of radiation throughout by limiting radiation emission from the tube
x-rays leave the housing through a
port
glass may become
electroplated
the envelope is made up of
glass
cathode is known as an
e- emitter
what are the 2 parts of the cathode
filament and focusing cup
focusing cup does what
focuses the e- to a single point
thermionic emission
tungsten wire will emit e- when heated by passage of a low amperage current
filament =
thoriated tungsten wire coil
anode side is the electrode ethat is
positive side of tube
greater the charge impacts force how?
greater the force of the e-
rotor is the portion that
rotates and is made up of copper and molybdenum
focal spot
limited area of target receives e- at any given spot
larger filament =
larger focal spot
smaller filament =
smaller focal spot
the effective focal spot size is _____ than actual focal spot size
less
actual size of focal spot is going to appear
smaller than it actually is
actual focal spot size
area struck by e- at any given instance during exposure
smaller focal size/smaller filament increases
resolution
magnitude of induced current depends on
- Strength of magnetic field
- Velocity magnetic field moving past conductor
- Angle of conductor to magnetic field
- Number of turns in the conductor
in a transformer the primary coil is connected to what and creates what?
connected to an AC source creating an expanding and collapsing electromagnetic field.
what happens in the primary coil vs secondary coil?
primary coil: creates a expanding/collapsing electromagnetic field.
Secondary creates: induced current
