Rad 121 Chapter 5 Electricity, Magnetism, and Electromagnetism

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x-ray imaging system coverts ____ into ____

electric energy into electromagnetic energy

the study of stationary or fixed electric charges is known as?

electrostatics

what are the five laws of electrostatics?

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

Repulsion/attraction Law:
like charges______
unlike charges_____

repel; attract

force between 2 charges is directly proportional to the product of their charges and inverserly proportional to the square of the distance between them is known as?

Coulombs Law

Charges reside on the external surface of conductors is known as?

Distribution Law

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

sharpest/roughest

process of electric charges being added/subtracted from an object is known as what?

electrifrication

objects rub against one another and electrons travel from one to the other is known as?

friction

two objects touch; electrons move from one object to another is known as?

Contact

Contact causes _______ of charges?

equalization

process of electrical fields acting on one another w/o contact is known as?

Induction

it is the most important method?

induction

induction method used in the operation of _______devices?

electronic

study of electric charges in motion is known as?

electrodynamics

movement of electrons or electricity results from the traveling of ______?

electrons

only _____ charges move along solid conductors

negative

Positive charges are fixed in the ?

nucleus

electrons move from _____ to _____ concentration

highest to lowest

______charge=object with more electrons

Negative

_____charge=object with weaker negative charge or an object with fewer electrons than another object

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

any substance through which electrons flow easliy is known as?

a conductor

Examples of conductors:

1)copper wire
2)aluminium
3)water

materials that resist electron flow is known as?

insulator

good insulators are:

1)rubber
2)plastic
3)glass

materials with the ability to conduct electricity under certain conditions and insulate under other conditions is known as?

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)

all electrons travel in the same direction is what type of current?

Direct

oscillating current is what type of current?

Alternating

Quantity of electrons flowing=

current

quantity is measured in what unit of current?

Ampere = A

x-ray is measured in what unit?

mA

causes number of electrons and x-rays produced to vary is known as what?

mA

force of electron tavel=

electric potential

electric potential exists when the flow of electrons has?

stopped

unit of electric potential is?

volt, V

electric potential determines the speed of electrons that determines penetrability which developes what?

contrast

amount of opposition to current flow is =

resistance or impedance

opposition is measured in

Ohms

unit of resistance is called?

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

electric potential is sometimes called

voltage

unit of electric potential is

volt (V)

V for US household is

110V

Electric power is known as

rate of doing

Electric power is measured in

watts (w)

electric power-Household appliances tend to operate between

500 to 1500w

x-ray machines require kW (electric power)

20 to 150kW

x-ray machines require V (electric potential)

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

what is the Ohms law equation

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

all circuit elements are conected in a line are known as

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

each element has an individual branch is known as

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

whart are some disadvantages to parallel circuits?

current increases, can over head=fire

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

fuse, circuit breaker

metal tab that melts with increased heat is known as?

fuse

pops open and can be reused and reset

circuit breaker

the voltage across the total circuit or any portion of the circuit is equal to the current time the resistance

Ohm's Law

Ohm's Law equation

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

what is the coulomb's law equation?

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

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