Basic Physics Flashcards
1
Q
energy of pos.
A
potential energy
2
Q
energy of motion
A
kinetic
3
Q
energy from chem reaction
A
chem energy
4
Q
energy from movement of e-‘s
A
electrical energy
5
Q
heat energy from movement of atoms
A
thermal energy
6
Q
energy resulting from nucleus of atom
A
nuclear energy
7
Q
energy that is emitted/transferred through matter
A
electromagnetic energy
8
Q
electromagnetic rad that is able to remove an e- from atom
A
ionizing rad
9
Q
how fast an object is moving
A
velocity
10
Q
rate of change of speed per unit of T
A
acceleration
11
Q
force applied on an object over a distance
A
work
12
Q
rate of doing work
A
power
13
Q
power is measured in?
A
watts
14
Q
what contains most of the mass of an atom?
A
nucleus
15
Q
represented by A
A
atomic mass
16
Q
of p+’s plus # of n0’s
A
atomic mass (A)
17
Q
of p+’s in nucleus
A
Z
18
Q
what determines the chem. element?
A
Z
19
Q
atoms w same # of p+’s but diff # of n0’s
A
isotopes
20
Q
force that holds e-‘s in orbit around the nucleus
A
electron-binding energy
21
Q
alpha particles are similar to what? and contain what?
A
He nucleus; 2 p+’s & 2 n0’s
22
Q
what are beta particles?
A
particulate rad that is e- like & emitted from nucleus of radioactive atom
23
Q
a bundle of photon energy is called a?
A
quantum
24
Q
frequency is measured in?
A
Hz
25
c in mi/s?
186,000 mi/s
26
origin of gamma rays?
nucleus of radioactive atoms
27
3 methods of electrification?
friction, contact & induction
28
material that allows the free flow of e-'s
conductor
29
object that prohibits the flow of e-'s
insulator
30
movement of e-'s along a conductor/pathway (electrical circuit)
electrical current
31
electrical current is measured in?
amperes
32
measured in volts; force w which e-'s move in an electrical circuit
electromotive force (EMF)
33
material that may act as an insulator or conductor under diff conditions
semiconductor
34
measured in ohms
electrical resistance
35
Ohm's law
V=IR
36
path along which e-'s flow; may be wired as series/II circuits
electrical circuits
37
representation of e- flow as AC
sine wave
38
what can magnetize a ferromagnetic material, like iron?
magnetic field
39
every magnet has a ______ & a _______
N & S pole
40
a coiled conductor (i.e. wire), through which an electrical current is flowing, has what?
overlapping magnetic fields
41
stacks fo wire coil through which electrical current flows, creating overlapping force field lines; a magnetic field is concentrated through the center of the coil
solenoid
42
solenoid w an Fe core that concentrates the magnetic field
electromagnet
43
process of causing an electrical current to flow in a conductor when it is placed w/in the magnetic field of another conductor
electromagnetic induction
44
opposing V created in a conductor by passing AC through it
self-induction
45
inducing current flow in a secondary coil by varying the current flow through a primary coil
mutual induction
46
device that converts mech. energy to electrical energy; usual output is AC
electrical generator
47
simplest type of current; V (& accompanying current) flow as a sine wave
single-phase, 2-pulse AC
48
3-phase, 6-pulse waveforms contain ____ pulses/sec
360
49
3-phase, 12-pulse waveforms contain ____ pulses/sec
720
50
what produces thousands of Hz's of electricity?
high-frequency generator
51
device that converts electrical energy to mech. energy
electrical motor
52
what requires an AC?
transformer (mutual induction)
53
transformer that +'s V from primary to secondary coil & -'s current in same proportion
step-up transformer
54
what is used in the XR circuit to + the V to the kV level for XR production
step-up transformer
55
transformer that -'s V from primary to secondary coil & +'s current in same proportion
step-down transformer
56
what is used in the filament portion of XR circuit to + current flow to cathode?
step-down transformer
57
transformer that contains an Fe core & a single winding of wire
autotransformer
58
what is used in the XR circuit to provide a small + in V before the step-up transformer
autotransformer
59
kVp settings are made at the?
autotransformer
60
process of changing AC to DC
rectification
61
what keeps the incoming V adjusted to the proper value of 220 V?
line voltage compensator
62
3 conditions necessary for XR production
1. e- source, 2. e- acceleration, 3. sudden stop of e- against target material
63
what is aka the variable transformer?
autotransformer
64
what is the source for selecting kVp?
autotransformer
65
secondary turns are selected by the tech using the?
kVp selector
66
what boosts the V to the kVp selected?
high-V step-up transformer
67
________ in the XR circuit indicates the V that is selected
prereading voltmeter
68
where is the pre reading voltmeter located?
btw the autotransformer & the high-voltage step-up transformer
69
what is used to regulate the duration of XR exposure?
timer
70
where is the mAs timer located?
after the secondary coil of the high-voltage step-up transformer
71
what measures the total tube current?
mAs timer
72
what provides the safest tube current in the shortest T possible?
mAs timer
73
what is microprocessor controlled and contained in most rad equipment?
electronic timer
74
what is used to provide consistency of rad quality
auto exposure control (AEC)
75
AEC relies on positioning skills bc?
the part must be accurately positioned over ionization sensors
76
what consists of a flat ionization chamber btw the pt & IR?
AEC
77
the level of ionization is ______ proportional to the density that will appear on the img
directly
78
what 2 things does the backup timer protect?
the pt from overexposure, and the tube from overheating
79
what is the shortest T w an AEC?
1 ms (0.001 sec)
80
modern generator that takes advtg of extremely short T capabilities & tube heat-loading potential
falling load generator
81
w falling load generator, XR tube current starts @ the ____ level possible for the 1st portion of the exposure
highest
82
falling load generators always use what to obtain a given mAs?
the shortest T possible
83
disadvantage of falling load generator?
exams where long exposure T's needed (orthostatic breathing)
84
what determines how much the V is stepped up?
turns ratio
85
the greater the turns ratio, the ____ the resulting kV (step-up transformer)
higher
86
formula for turns ratio?
Ns/Np
87
XR tube requires _____ to operate properly
DC
88
solid-state semiconductor diodes are what?
rectifiers (convert AC to DC)
89
rectifiers consist of?
silicon-based n-type & p-type semiconductors
90
where is the rectifier located?
btw the step-up transformer & the XR tube
91
single-phase results in what % voltage ripple?
100%
92
how many diodes provides full-wave rectification for single-phase generators?
4
93
how many diodes provides full-wave rectification for three-phase generators?
6 or 12 diodes
94
when 3-phase current is used, voltage ______________ during exposure
never drops to 0
95
voltage ripple for 3-phase, 6-pulse?
13%
96
voltage ripple for 3-phase, 12-pulse?
4%
97
voltage ripple for high-frequency?
1%
98
how much voltage is actually used in a 3-phase, 12-pulse generator?
96% of kVp set
99
which waveforms produce higher average photon energy?
3-phase, full-wave rectified waveforms (35% higher for 3-phase, 6-pulse & 41% higher for 3-phase, 12-pulse)
100
what measures the tube current?
mA meter
101
where is mA meter located?
btw rectifier & XR tube
102
mA control provides V from autotransformer to?
step-down transformer
103
what -'s V & +'s current to heat the filament?
step-down transformer
104
what is the neg electrode in the XR tube?
cathode
105
cathode contains how many filaments?
2 (sm & lg)
106
over time, what leads to tube failure?
filaments vaporize & coat the inner surface of XR tube w tungsten
107
what is it called when during an XR exposure, 1 filament is heated to a level that causes e-'s to be "boiled off" to prepare for XR production
thermionic emission
108
what surrounds the filaments in the cathode?
the focusing cup
109
the focusing cup has what applied to concentrate the e-'s boiling off the filaments into a narrow stream toward target?
neg. charge
110
what is the pos. electrode in the XR tube?
anode
111
rotation of the anode target allows greater what?
heat dissipation
112
e-'s strike the target on the?
focal track/spot
113
focal track/spot is beveled, producing the?
target angle
114
the larger the actual focal spot, the greater the _____ _____
heat capacity
115
the smaller the effective focal spot, the greater the?
img sharpness
116
glass envelope has a vacuum so e-'s from filament don't what?
collide w atoms of gas
117
what is in the glass envelope that allows XRs to escape?
tube window
118
indicates the kVp that will flow through the XR tube during exposure
pre-reading voltmeter
119
regulates duration of XR exposure
timer
120
what is placed btw pt & IR
AEC
121
what provides extremely short exposure T's by taking advtg of tube heat-loading potential
falling load generator
122
what is the high-V transformer?
step-up
123
what contains the filaments, the source of e-'s for exposure
cathode
124
what consists of the rotor & exposure button
exposure switch
125
what encases tube , Al lined w Pb?
tube housing
126
which wavelengths are more penetrating?
short
127
what removes long wavelength rays?
beam filtration
128
calculation of the total heat produced during an XR exposure
heat units
129
digi-fluoro usually eliminates what?
postprocedure "overhead" img's
130
smallest particle of an element that retains it's characteristics of the element?
atom
131
in digi-fluoro, the img must be turned into digital form by what device?
analog-to-digital converter
132
XRs travel in bundles of energy called
photons
133
atomic mass?
p+'s plus # n0's
134
what's used to ensure consistency of rad quality from one exposure to the next?
AEC
135
when a predetermined level of ionization reaches ionization chamber, the machine?
terminates exposure
136
what type of XR machine uses a continually decreasing mA for the shortest T's possible?
falling load generator
137
what type of current is needed for proper operation of XR tube?
DC
138
outer shell of an atom can contain no more than 8 e-'s
octet rule
139
He nuclei & beta particles are examples of?
particulate radiation
140
electromagnetic radiation travels in ______ along _______
waves; straight path
141
speed that XRs travel?
speed of light, 186,000 miles/second
142
waves of rad are called
sine waves
143
distance from peak to peak of sine wave
wavelength
144
of waves passing a point per unit T
frequency
145
wavelength & frequency are ______ proportional
inversely
146
XR beam changes as it travels through the pt is called
attenuation
147
I of rad is inversely proportional to the square of D btw the rad source & pt
inverse square law
148
as rad strikes matter the energy is transferred to the atoms according to?
the law of conservation of energy
149
a ____________ always surrounds an electrical charge in motion
magnetic field
150
current flows back and forth in
AC
151
what allows the free flow of e-'s?
conductors
152
unit of potential diff
volt
153
path of electrical current
circuit
154
process of causing an electrical current to flow in a conductor when it is placed in the magnetic field of another conductor?
electromagnetic induction
155
self-induction is used in the operation of what?
autotransformer
156
strength of the magnetic field in a transformer is increased by
coiling the wires & letting their magnetic fields overlap
157
electricity is supplied to the imaging dept by a
generator
158
electricity provided to the rad dept.
60 Hz AC
159
electricity provided to the rad dept. operates at
120 pulses per sec
160
primary advtg of 3-phase power is that
V never drops to 0
161
a variable transformer that is used to select kVp for the XR circuit is?
autotransformer
162
what transformer boosts the V to kV?
step-up
163
V in XR machine kept constant by
line voltage compensator
164
where does thermionic emission occur?
cathode
165
what device is pre-reading?
kVp meter
166
which device is electronic, w increments of 0.001 sec?
timer
167
what changes AC to DC?
rectifier
168
what is surrounded by a negatively charged focusing cup
filament
169
what is composed of solid-state, silicon-based diodes?
rectifier
170
what's located in the XR circuit btw the high-voltage transformer & the XR tube?
rectifier
171
what measures tube current?
mA meter?
172
what spins @ 3300 or 10,000 rpm?
anode
173
what device uses max heat storage ability of the tube to deliver mAs?
falling load generator
174
source of bream's & char. XR's
anode
175
most commonly used AEC?
ionization chamber
176
what is turned by a rotor?
anode
177
activating the rotor
reduce tube life
178
when making an exposure, the tech should...
activate the rotor & exposure switch in one contin. motion
179
thermionic emission causes?
e-'s to boil off filament
180
the e- stream passes from cathode to anode bc of ______ passing through the XR tube
current
181
heat is produced in XR tube as?
e-'s interact w target material
182
most of the energy conversion in XR tube produces?
heat
183
XRs are produced as incident e-'s interact w target atoms by a process called
bremsstrahlung
184
XRs are produced as incident e-'s interact w inner shell e-'s in target atoms by a process called
characteristic
185
percentage of energy in XR tube that is converted into XRs
1%
186
what can ionize matter/gas & affect film emulsion
XRs
187
the XR beam is ______/______ (consisting of many diff energies/wavelengths)
heterogenous/polyenergetic
188
XR emission spectrum consists of:
discrete (char. XRs) & contin. (brems XRs)
189
primary purpose of filtration
rad protection
190
total filtration is no less than
2.5 mm Al equivalent
191
what makes up inherent filtration?
glass envelope, tube housing, oil
192
what makes up added filtration?
Al
193
what produces pulsating DC w 120 pulses per sec & 100% ripple
single-phase, full-wave rectification
194
what produces DC w 13% ripple?
3-phase, 6-pulse
195
what produces DC w 4% ripple?
3-phase, 12-pulse
196
when changing from single-phase to 3-phase, 6-pulse the avg photon energy increase?
35%
197
when changing from single-phase to 3-phase, 12-pulse the avg photon energy increase?
41%
198
marks on focal track/spot of anode from bombardment of e-'s
pitting
199
what states that electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance btw them
Coulomb's law
200
what states that energy of a photon is directly proportional to its frequency
Planck's Quantum Theory
201
what can be created by friction, contact, or induction?
electrification
202
no resistance to e- flow below a critical temp (titanium, niobium)
superconductor
203
any substance through which e-'s flow easily; variable resistance; obey Ohm's law; requires V (copper, Al)
conductor
204
material that under some circumstances behave as insulator and in others a conductor; basis for computers (silicon, germanium)
semiconductor
205
does not allow e- flow; extremely high resistance (plastic, rubber, glass)
insulator
206
relationship btw electric resistance & electric current?
inversely
207
Ohm's law
V=IR (I is current in amps)
208
unit of current
ampere (A)
209
unit of power
watts (W)
210
formula for power?
power (W) = V x current (A)
| P=IV, or P=IIR
211
formula for total resistance in a series circuit
Rt = R1 + R2 + R3
212
formula for total resistance in a II circuit
1/Rt = 1/R1 + 1/R2 + 1/R3
213
lines of magnetic field are always
closed loops
214
ability of material to attract lines of magnetic field intensity
magnetic permeability
215
degree to which material can be magnetized
magnetic susceptibility
216
very slightly attracted to a magnet & ar loosely influenced by an external magnetic field; weakly attracted to both poles of a magnetic field
paramagnetic materials (MRI contrast)
217
weakly repelled by either magnetic pole; cannot be artificially magnetized; not attracted to magnet
diamagnetic materials (water, plastic)
218
strongly attracted by a magnet; usually can be permanently magnetized by exposure to a magnetic field
ferromagnetic materials (iron, nickel, cobalt, alnico)
219
lines of magnetic filed leave ____ pole and enter _____ pole
N to S
220
transform mechanical energy into electrical energy
electric generators
221
transform electrical energy into mechanical energy
electric motors
222
states that an electric current is induced in a circuit if some part of that circuit is in a changing magnetic field (no current is induced if the magnetic field is not moving)
Faraday's Law
223
magnitude of induced current depends on what 4 factors
strength & speed of magnetic field, # of turns in the conductor & angle of conductor to magnetic field
224
energy dissipated by resistance in the wire used to wind a coil is called
copper loss
225
magnetic friction in the core due to changing magnetic field
hysteresis loss
226
power loss due to electric currents induced in the core
eddy current loss
227
how many types of transformer loss?
3 (copper, hysteresis, eddy current)
228
2nd law of electromagnetism thats states that the induced current flows in a direction such that it opposes the action that induces it
Lenz's Law
229
if an atom loses an e-, it becomes a?
pos. ion
230
largest source of natural enviro rad?
radon
231
radon is produced by the natural decay of
Uranium
232
XR's discovered on?
Nov. 8 1895
233
most common hip break is
femur neck
234
cecum located in
RLQ
