Physics (Electrostatics and Magnetism Chapter 4)

fundamental unit of charge

coulomb (C)

electric current

if electric potential (voltage) is applied to objects such as copper wire, then electrons flow along the wire through a conductor and is called a electric current or electricity

resistance?

interferes with the flow of electrons

the electric field points __________ for a negative charge?

inward

the volt is potential energy/unit charge or a?

joule/coulomb (J/C)

repulsion and attraction for magnetism

like poles repel; unlike poles attract, like lines of force repel and unlike lines of force attract

the stronger the magnetic field, the greater the # of

lines of flux or greater flux density

the force fields that are created when magnetic dipoles orient to create a magnet are called?

lines of force, or lines of flux, or magnetic field

materials that have the ability to attract iron are classified as having a strong?

magnetic field

ferromagnetic

material (iron, cobalt and nickel) that is strongly attracted by a magnet and can usually be permanently magnetized by exposure to a magnetic field. these materials have a majority of their dipoles lying in the same direction, thus setting up a natural magnet.

semiconductors

material that under some conditions behaves as a insulator and in other conditions behaves as a conductor, silicon, germanium

the stronger the magnetic field the?

more lines of flux

electric resistance is measured in ?

ohms

when a charged particle is in motion, a magnetic force field _____________ to the motion will be created

perpendicular

A = ?

unit of electric current

what is the unit of electric potential or "potential difference?"

volt

V = ?

voltage

one watt is = to

1A of current flowing through an electric potential of 1V. Power (W) = voltage (V) x current (A).

Distribution

Charges reside on the external surfaces of conductors and equally throughout nonconductors.

Electric charge of a conductor is _____ along the _____ _____ of the surface.

Concentrated, Sharpest Curvature

If an electric potential is applied to objects such as copper wire, then electrons move along the wire. This is called _____ _____ or __________.

Electric Current or Electricity

induction

Electrification by induction is the process of electrical fields acting on one another without contact. ex: rubber ballon sticking to wall and happens because of repulsion and attraction

friction

Electrification by friction occurs when one object is rubbed against another, and, due to differences in the number of electrons available on each, electrons travel from one to the other

contact

Electrification by contact occurs when two objects touch, permitting the transfer of electrons to move from one to the other.

Coulomb's Law

F=K Q₁*Q₂/d², magnitude of force between two charges F = force (newton) Q1 = charge of object 1 (coulomb) Q2 = charge of object 2 (coulomb) d = distance between objects (meters) k = proportionality constant

repulsion-attraction

Like charges repel; unlike charges attract

The Coulomb's law

The force between two charges is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance between them

Concentration

The greatest concentration of charge will be on the surface where the curvature is greatest or sharpest, ex: cattle prod

Magnetic Moment

The proton in a hydrogen nucleus spins on its axis and creates a nuclear magnetic dipole.

ohms law

V=IR V = is the electric potential in volts (V) I = is the electric current is amperes (A) R = is the electric resistance in ohms (also do triangle, V on top and I and R across from each other and underneath V)

Electric potential

a system that possesses potential energy is a system w/ stored energy, such a system has the ability to do work when this energy is released

energy?

ability to do work and can not be created nor destroyed

potential difference?

ability to move a charge; volt

CURRENT in which electrons oscillate back and forth ?

alternating current (AC)

electric current is measured in

amperes (A)

electrification is?

an excess of electrons

insulator

any material that does not allow electron flow, glass, rubber, plastic and air and other earthlike materials

conductor

any substance through which electrons flow, most metals, copper is the best, and water due to salts and impurities it contains

opposite charges?

attract

electric charges associated with an electron and a proton and have the same magnitude but different?

charges

Electrification can be created by? "electrified"

contact, friction, electric induction

the magnitude of the electrostatic force is given by what law?

coulombs law

magnetic fields are?

dipoles

electrons that FLOW in on direction along the conductor, the ELECTRIC CURRENT is called ?

direct current (DC)

1 ampere is = to an?

electric charge of 1 C flowing through a conductor each second

the smallest unit of electric charge is?

electron and proton

the force of attraction b/w unlike charges or repulsion b/w the like charges is attributable to the electric field, it is called

electrostatic force

I = ?

equation symbol for current

R = ?

equation symbol for resistance

magnetic poles

every magnet has 2 poles, a north and south pole and will always have a north and south pole even it cut in half

flux density is determined both by?

field strength and by the are in which the lines of flux are located

inverse square law for magnetism

force b/w 2 magnetic fields is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance b/w them......as an object gets further away, the influencing field decreases b/c of the increased area it affects

matter

has mass, takes up space and has energy equivalence

the electric ground (Earth)

hold and acts as a reservoir for stray electric charges; in this capacity it is called an electric ground

superconductivity

is the property of some materials to exhibit no resistance below a critical temp (niobium and titanium)...electric current exists without voltage

uniformly strong magnetic field is referred to as a ?

magnet

groups of atoms w/ this net magnetic field are know as?

magnetic dipoles or magnetic domains

diamagnetic

materials, such as beryllium, bismuth and lead, are actually weakly REPELLED by all magnetic fields, including both North and South poles. water is slightly diamagnetic.

paramagnetic

materials, such as platinum and aluminum, have low permeability and weak ATTRACTION magnetic fields. only slight majority of dipoles in the same direction. MRI are usually paramagnetic

nonmagnetic

materials, such as wood, glass, rubber and plastic and NOT affected by magnetic fields and cannot be magnetized. (electrons in this material do not have the ability to freely orient themselves to external magnetic lines of force)

atoms having a significant # of electrons w/ their magnetic moments in the same direction, especially when the outer shells are involved, will exhibit a ?

net magnetic field in a distinct direction

with electrified copper wire, excess electrons are distributed on the ___________ ____________?

outer surface

the electric field points __________ for a positive charge?

outward

ease with which a material can be magnetized?

permeability

increasing electric resistance results in a ?

reduced electric current

positive charges?

repel

5 laws of electrostatics?

repulsion-attraction, the inverse square law, distribution, concentration, movement

electric circuit?

resistance is controlled, current flows in a closed path

ability of a material to stay magnetized

retentivity

magnetism is fundamental property of ?

some forms of matter

lines of force always flow _________ to __________ w/in the magnet and never intersect?

south to north

spin magnetic movement

spinning of an individual electron

magnetic poles are induced through the?

temporary orientation of the dipoles

SI unit for magnetic flux density? British unit?

tesla (T), British unit=gauss (G)

inverse square relationship

the electrostatic force is very strong when objects are close but decrease rapidly as objects separate

ohms law meaning

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

What is the primary function of an x-ray machine?

to convert kinetic or electric energy to electromagnetic energy

when you cut a magnet in half you get?

two smaller sized magnets with north and south poles

Electric charge distribution is _____ throughout or on the surface.

uniform

omega sign = ?

unit of resistance "ohm"

electric potential

voltage

electric power is measured in

watts (W)

SI unit for magnetic flux?

weber (Wb)

magnetic induction

when a non-magnetized iron bar is brought w/in the lines of force of a strong magnet, the dipoles will temporarily align themselves w/ the lines of the force passing through the iron bar. If the bar is removed from the field after a short while, the dipoles will return to their random orientation, thus leaving the bar unmagnetized.

electric charges have potential energy b/c

when positioned close to each other, like electric chargers have electric potential energy b/c they can do work when they fly apart

electric circuits

when the resistance is controlled and the conductor is made into a closed path, the result is an electric circuit

electric charges have potential energy b/c they have the ability to do ?

work

electrodynamics

"electricity," study of electric charges in motion

the ampere is proportional to the _______ of electrons flowing in the electric circuit?

#

dipoles

-NO smallest unit of magnetism -magnetic field that always has 2 poles, north and south

magnetism?

-difficult to detect and measure -cannot sense magnetism -any charged particle has a magnetic field associated with it (in motion) -ELECTROMAGNETIC RADIATION CARRIES BOTH AN ELECTRIC AND A MAGNETIC FIELD AS IT TRAVELS THROUGH SPACE

magnetic field lines?

-leave from the north pole and enter the south pole -lines are imaginary, but may be demonstrated with a magnet and iron fillings

magnetic force

-magnetic force is proportional to the product of the magnetic pole strengths and inversely proportional to the square of the distance between them; ex: if the distance between two bar magnets is halved, the magnetic force increases by four times

1 V =

1 joule/coulomb

laws governing magnetism

1) repulsion and attraction 2) inverse square law 3)magnetic poles

1 (C) = ?

6.3 x10^18 electron charges

C/s =?

Ampere

lines of force always flow from _________ to _______ outside the magnet and never intersect?

North to south

Movement

Only negative charges move along solid conductors.

electric power

P = IV (formula) P = power in watts I = current in amperes V= electric potential in volts