Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
82 Cards in this Set
- Front
- Back
|
Primary function of an X-ray imaging system
|
To convert electric energy into electromagnetic energy
|
|
|
Conversion that takes place in an X-ray tube
|
Most of the electric energy is transformed into heat & some of it into x-rays
|
|
|
Matter has _______ and ______ ______ and may also have ______ ______.
|
Mass
Energy equivalence Electric charge |
|
|
Protons are _____ inside the nucleus
|
Fixed
Not free to move |
|
|
An Electron has __?___
|
1 Unit of negative charge
|
|
|
A proton has __?__
|
1 unit of positive charge
|
|
|
Electric charges associated with an electron and a proton have _?_
|
The same maginitude but opposite signs
|
|
|
The total net charge of all matter in the universe -
|
Neutral
|
|
|
Removal of the outer-shell electrons
|
Electrification
|
|
|
Removal of the outer-shell electrons electrifies the substance from which they are removed and results in __?__
|
Static electricity
|
|
|
3 ways electrification occurs;
|
Contact
Friction Induction |
|
|
an object is said to be electrified if __?__
|
It has too few or too many electrons
|
|
|
Fundamental unit of electric charge is __?__
|
Coulomb (C)
|
|
|
1 (C) coulomb = _?_
|
6.3 x 10(18) electron charges
|
|
|
A measure of the quantity of electrostatic charge
|
mAs
|
|
|
4 general laws of electrostatics
|
1) Unlike charges attract /
like charges repel 2) The electrostatic force is directly proportional to the product of the electrostatic charges & inversely proportional to the square of the distance between them (Coulomb's Law) 3) Charges reside on the external surface of solid conductors & are equally distributed throughout non-conductors 4) The electric charge of a conductor is concentrated along the sharpest curvature of its surface |
|
|
The force of attraction between unlike charges or repulsion between like charges is due to __?__
|
The electric field
|
|
|
Electrostatic field is also referred to as __?__
|
Electrostatic force
|
|
|
Electric charges have __?__
|
Potential energy
|
|
|
The unit of electric potential is __?__
|
The Volt (v)
|
|
|
The movement of electrons is __?__
|
work
|
|
|
Electric potential is somtimes termed __?__
|
Electromotive force (EMF)
or Voltage |
|
|
The EMF (electromotive force) for homes is __?__
|
120 v
|
|
|
The EMF (electromotive force) for X-ray machines is __?__
|
240 v
|
|
|
In an X-Ray tube EMF is measure in __?__
|
kV
|
|
|
The study of electric charges in motion is __?__
|
Electrodynamics
|
|
|
Electrodynamics is recognized as __?__
|
Electricity
|
|
|
The flow of electrons
|
Electric Current
|
|
|
Electrons move from ______ to _______.
|
High concentration to low concentration
|
|
|
Electric current goes from _____ to ____ poles while electron flow actually goes from ______ to ______ poles.
|
Electric current flow = positive to negative
Electron flow = negative to positive |
|
|
Electric current flows
|
positive to negative
|
|
|
Electron flow goes
|
from negative to positive
|
|
|
A conductor
|
Any substance through which electrons flow easily
|
|
|
An insulator
|
Any material that does not allow the electron flow
|
|
|
4 electrical states of matter;
|
Super conductor
Conductor Semi conductor Insulator |
|
|
Ohm's law
|
IR = V
|
|
|
Electrostatics
|
The science of stationary electric charges
|
|
|
The smallest units of electric charge
|
The electron
|
|
|
An abnormal state relieved by providing some other object from which excess electrons can be transferred -
|
Electrifications
|
|
|
Electrification occurs because __?__
|
Because of the movement of negative electric charges
|
|
|
Positive electric charges -
|
Do not move
|
|
|
The earth is called an _____ _____ since it behaves as a huge reservoir for stray electric charges
|
electric ground
|
|
|
Series Circuit Rules
|
I(t) = I(1) = I(2) = I(3)
R(t) = R(1) + R(2) + R(3) V(t) = V(1) + V(2) + V(3) |
|
|
Parallel Circuit Rules
|
V(t) = V(1) = V(2) = V(3)
I(t) = I(1) + I(2) + I(3) 1/R(t)= 1/R(1) + 1/R(2) + 1/R(3) |
|
|
Superconductor
|
A material that offers no resistance to electron flow
|
|
|
Semiconductor
|
A material that can behave as an insulator or can act as a conductor
|
|
|
The smallest unit of electric charge ________
|
An electron
|
|
|
What is the unit of current?
|
Ampere (Amp)
|
|
|
Current in the X-ray tube is __?__
|
mA
|
|
|
An electric current is __?__
|
The flow of electrons
|
|
|
The force or electrical pressure that produces electron movement and current flow
|
Voltage
|
|
|
What measures the electrical potential that causes electrons to flow in a conductor
|
Voltage
|
|
|
One kilovolt is equal to _________ volts
|
1000
or 10(3) volts |
|
|
Electrical potential is measured in __?__ and is sometimes called the _______
|
Volts
EMF |
|
|
The filament of an x-ray tube is supplied with a __________
|
High current (2-5 amperes)
|
|
|
The X-ray tube is supplied with a _______________
|
Lower current
25mA to 2500 mA |
|
|
Voltages of _________ to ______ are used in x-ray circuits
|
20,000 to 120,000 V
or 20 to 120 kV |
|
|
The opposition to current flow
|
Resistance
|
|
|
A longer wire has ??
|
More resistence
|
|
|
Larger diameter wire has _______ resistence
|
Less resistence
|
|
|
A smaller diameter wire has ______ resistence
|
More resistence - because there is less area for current flow
|
|
|
Ohm's Law states
|
That the voltage across the total circuit or any portion of the circuit is equal to the current multiplied by the resistence
|
|
|
Example of an Insulator
|
Rubber
Glass |
|
|
Example of a semiconductor
|
Silicon
Germanuim |
|
|
Example of a conductor
|
Copper
Aluminum |
|
|
Example of a superconductor
|
Niobium
Titanium |
|
|
The property of some materials to exhibit no resistance below a critical temperature is called
|
Superconductivity
|
|
|
Electric potential is measured in ___?___
|
Volts (V)
|
|
|
Electric resistance is measured in ___?___
|
Ohms
|
|
|
In a series circuit
|
All circuit elements are connected in a line along the same conductor
|
|
|
A parallel circuit contains elements that are .......
|
Connected at their ends rather than lying in a line along a conductor.
|
|
|
Electric energy is supplied to the X-ray imaging system in the form of .......
|
Well-controlled electric current
|
|
|
Electric energy is transformed into _________, and some of it into __________.
|
Heat
X-rays |
|
|
Power loss formula
|
P = I(2)R
|
|
|
Power is measured in ????
|
Watts or Kilowatts
|
|
|
Power equation
|
P = IV
|
|
|
Power describes ????
|
The amount of work done
or Amount of energy used per second |
|
|
Electric Power is _________
|
The rate of energy use
|
|
|
The US standard AC electric current has a frequency of ???
|
60 cycles per second
or 60 Hz per second |
|
|
One AC cycle consists of _______
|
One half positive current flow and one half negative current flow
|
|
|
Alternating current (AC)
|
Electrons which oscillate back and forth
|
|
|
Direct Current (DC)
|
Electrons which flow in one direction along the conductor
|
