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69 Cards in this Set
 Front
 Back
Primary Funciton of Xray imaging system is to ..

convert electrical energy into electromagnetic energy (conversion of electric current into xrays)


Smallest unit of Positive Charge

Protons


Smallest unit of negative charge

Electrons


Electrons are free to move between

Orbits and Atoms


Electricity concerns the distribution and movement of ...

electrons


Electricity (electric charge) comes in units that are

either positive or negative in charge


Free to move from one atom to another.

Electrons


Fixed in the nucleus and cannot move around.

Protons


The study of stationary electric charges

Electrostatics


Charges at rest

Electrostatics


Laws of Electrostatics

RepulsionAttraction
Inverse Square Law Distribution Concentration Movement 

Unlike Charges

Attract


Like Charges

Repel


Force between two charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them

COULOMB LAW (inverse square law)


Charges reside on external surface of conductors (an attempt to repel from each other)

Distribution


Electric charge DISTRIBUTION is ... throughout or on the surface of conductors

UNIFORM


The greatest CONCENTRATION of charges will gather at the ....

sharpest area of curvature


Only .... charges move along solid conductors

Negative


Adding or removing electrons

Electrification


Electrification created by

Friction,
Contact, Induction 

Occurs when one object is rubbed on another (rub feet on wool rug) (Combining hair during winter)

Friction


Occurs when two objects touch (permits electrons to move from one object to another

Contact


Electrification by contact

Static Discharge


Resevoir for straty electric charges .. electric ground

Earth


unit of electric charge

Coulomb (1C = 6.3x10)


When an electric potential is applied to a copper wire, electrons move along the wire creating an electric current or ....

Electricity


Quantity of electrons flowing

Current (I)


Force with which electrons travel

Potential Difference (V) Voltage


Opposition to currtent flow

Impedance or Resistance (R)


Direction of electron travel

AC / DC


Electrons move from areas of .. concentration to .... concentration

High to Low


Current flow requires an ... of charge between two points

IMBALANCE


Flow of electrons through a conductor or semiconductor is known as

CURRENT


A current is produced whenever charges are ...

in motion (electrons are moving)


Quantity of electrons flowing

Ampere
1 ampere (A)= 1 coulomb/second) 

Electric charges have ... energy to do work

Potential (stored energy)


Force that drives the electrons

Electrical Potential


Unit of Electrical Potential

Volt


Electrical Potential is called the

Voltage


The higher the ... the greater the ... to do work

Voltage, Potential


Electromotive Force (EMF)

the force or strength of electron flow; also known as potential difference (V)


EMF used to do work

Voltage


Residential voltage is

110 V


Xray imaging systems require how much voltage?

220 V


The unit of potential difference EMF (V)

Joule/Coulomb (J/C)


Difference in charge between 2 points required to make charges (electrons) move.

Voltage
(Greater voltages make charges (electrons) move faster. 

Opposition to the flow of current through a conducting path

Electrical Resistance


All materials have varying degress of resistance, depending on ...

strength of electrical bonds


Resistance is measured in

Ohms


The symbol for Ohms

R


Eletrical resistance is dependent on what 4 things?

Materials conductivity
Length Diameter Temperature 

Any substance through which electrons flow easily.
Touching results in shoch 
Conductors


Any material that dose not allow electron flow
Touching does not result in shock 
Insulators


Copper
Aluminum Water 
Conductors


Rubber
Glass Porcelain 
Insulators


Material that under some circumstances behaves as an insulator and in other conditions behaves as a conductor

Semiconductors


Silicon
Germanium 
Semiconductors


Dependent on configuartion of atom's valence band, conduction band

Materials Conductivity


How is length related to resistance?

Directly related


How is diameter related to resistance?

Inversely related


How is temperature related to resistance?

Directly related; Increased atomic motion due to increased temperatrue prevents electrons from flowing freely.


Under normal conditions, to have a current flow theough a circuit path there must be:

a voltage and a complete path


The voltage across the total circuit or any portion of the circuit is equal to the current times the resistanct

Ohm's Law


V = IR
V = Voltage (volts) I = Current (amps) R = Resistance (ohms) 
Ohm's Law


V = IR
I = V/R R = V/I 
Ohm's Law


Measured in Watts

Electric Power


Xray imaging systems require ... of electric power

20  150 kw


... determines how much work a circuit can do

Watts


P = IV
P = I(squared)R 
Power formula based on Ohm's Law
