# Rad 121 Chapter 5 Electricity, Magnetism, and Electromagnetism

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### x-ray imaging system coverts ____ into ____

electric energy into electromagnetic energy

electrostatics

### what are the five laws of electrostatics?

1)concentration
2)distribution
3)attration/repulsion
4)inverse square law
5) movement

repel; attract

Coulombs Law

Distribution Law

### Concentration Law: greatest distribution of charges on surface on ________ curve?

sharpest/roughest

electrifrication

friction

Contact

equalization

Induction

induction

electronic

electrodynamics

electrons

negative

nucleus

### electrons move from _____ to _____ concentration

highest to lowest

Negative

positive

### electric current travels from _____ to _____ poles

postive to negative

### electric /electron flow travels from ____ to ____ poles

negative to positive

### electric current occurs in:

1)vacuum (x-ray tube)
2)neon gas
3) inonic solutions & metals

a conductor

1)copper wire
2)aluminium
3)water

insulator

1)rubber
2)plastic
3)glass

semiconductors

### Two examples of semiconductors are:

silicon and germanium

### allows electrons to flow freely w/no resistance below certain temperatures is known as?

superconductivity

### superconductivity works with what kind of temepratures?

very cold (liquid nitrogen)

### two examples of superconductivity is?

noibiun and titanium wire which are used in MRI

### Nature of electron flow is?

1)direction of electron travel
2)quantity of electrons flowing
3)force of electron travel
4)opposition to current flow

### what are the two currents for direction of electron flow?

Direct current (DC)
Alternating current (AC)

Direct

Alternating

current

Ampere = A

mA

mA

### force of electron tavel=

electric potential

stopped

volt, V

contrast

### amount of opposition to current flow is =

resistance or impedance

Ohms

Ohm

### what are the 3 factors that impede the flow of electrons?

1)Length of the conductor
2)crosssectional diameter of the conductor
3)temperature of the conductor

### Length of the conductor-as length doubles, resistance does what? and has what proportional relationship?

doubles, directly

### crosssectional diameter of the conductor-as diameter doubles, resistance does what? and has what type of relationship

halved, inversely

### temperature of the conductor-

causes increase or decreases of resistance depending on conductor, insulator or semiconductor

voltage

volt (V)

110V

rate of doing

watts (w)

500 to 1500w

20 to 150kW

220V

### Ohm's law is a interrelationship of

current, potential, and resistance

### for Ohms law voltage across the total circuit is equal to the

current x resistance

V=IR

### V=

electric potential in volts

### I=

current in amperes

### R=

resistance in ohms

### electric power formula

P=current x voltage

### formed by controlling the resistance in the closed path of a conductor is known as?

electric circuits

series circuit

### what are some advantages to series circuits?

cheap, easy to fix, repair, replace. greater potential difference=greater total voltage. current remains the same

### what are some disadvantages to series circuits?

all resistances have to be operable. failure of one=the whole supply. resistance increases

parallel circuit

### what are some advantages to parallel circuits?

elements can operate at lower voltage bc voltage doesnt change. failure of one element doesnt interrupt the other . resistance goes down

### what are 2 safeguards that break the circuit before a dangerous temeprature is reached?

fuse, circuit breaker

fuse

circuit breaker

Ohm's Law

V=IR
I=V/R
R=V/I

### semiconductor

A material that when combined with some other material can be turned into an insulator or a conductor.

### conductor

a substance that readily conducts e.g. electricity and heat

### insulator

a material that does not allow heat or electrons to move through it easily

F=k Q^AQ^B/d^2

Example: