Forces and Fields/Magnetism

Question 1

Electrostatics

Answer 1

the study of charges not in motion

Question 2

Law of Conservation of Charge

Answer 2

the net amount of electric charge produced in any process is zero. you cannot create or destroy charges

Question 3

what is an ion

Answer 3

an atom that has lost or gained electrons

Question 4

conductivity

Answer 4

a way of describing how easily charges move through a material

Question 5

insulators

Answer 5

charges do not move easily. (most materials besides metals (plastic, glass, rubber))

Question 6

conductors

Answer 6

charges move easily, they are free moving. most metals

Question 7

separation of charge (polarization)

Answer 7

movement of electrons in an neutral object where one side becomes positive and the other side becomes negative.

Question 8

charging by friction

Answer 8

rubbing two materials together, causing electrons to transfer from one material to the other. some materials hold electrons better than others. results in oppositely charged objects

Question 9

charging by induction

Answer 9

when a charged object comes close enough to induce a charge (no contact), causing a redistribution/separation of charges. results in oppositely charged objects

Question 10

charging by conduction

Answer 10

when a charged object comes in contact with another and electrons transfer from one to the other. charges are shared this results in identically charged objects

Question 11

grounding

Answer 11

the process of connecting a charged object to the earth which will cause the grounded object to neutralize in terms of charge.

Question 12

electroscope

Answer 12

an instrument used to detect the presence and nature of a charge. the more the leaves diverge, the greater the charge

Question 13

Coulomb’s Law

Answer 13

describes the electrostatic force between two charged objects in relation to the distance between them. Fe = (kq1q2) / r^2

Question 14

What did Coulomb use to study the relationship between distance and charge?

Answer 14

a torsion balance apparatus

Question 15

Fields

Answer 15

arc spheres of influence and cause an ‘action at a distance’. number of field lines indicate strength

Question 16

vector fields

Answer 16

have specific directions as well as magnitude

Question 17

Electric Fields

Answer 17

radiate away from positive charge and towards negative charge.

Question 18

test charge

Answer 18

the mathematically perfect charge that could be brought near another charge (source charge) to measure the source charge’s electric field.

Question 19

potential difference

Answer 19

the work required to move a charge between two points in an electric field

Question 20

current

Answer 20

the flow rate of an electric charge

Question 21

What was Millikan’s experiment

Answer 21

he used the the electric field created by two parallel plates to determine the charge of an electron (the oil drop experiment)

Question 22

how did Millikan’s oil drop experiment work

Answer 22

he dropped oil droplets between two charged plates. the positive ones would accelerate down, towards the negative plate, the negative ones would fall enough for Fe=Fg

Question 23

can causing by induction cause permanent charge changes?

Answer 23

yes. if an something neutral is grounded and a positive rod is brought near it, the electrons in the object and more electrons from the ground will move towards the positive rod. when the ground is removed, there are more electrons than there where before.

Question 24

who developed the idea of field lines?

Answer 24

Michael Faraday

Question 25

how can work be done in an electrical system

Answer 25

pull opposite charges apart or push like charges together

Question 26

what does a cathode ray tube do

Answer 26

it uses electric fields to accelerate electrons (aka electron gun)

Question 27

cathode is connected to

Answer 27

negative terminal

Question 28

anode in connected to

Answer 28

positive terminal

Question 29

which metals experience noticeable net force in a magnetic field?

Answer 29

iron, copper, nickel

Question 30

what are magnetic fields caused by

Answer 30

moving charges

Question 31

what causes magnets

Answer 31

electrons spinning, causing magnetic fields

Question 32

what are domains

Answer 32

small magnets inside magnets.

Question 33

which direction do magnetic field lines point?

Answer 33

towards south and away form north

Question 34

what did Hans Christian Oersted discover?

Answer 34

electrons moving in the form of current also produce electric fields

Question 35

First Hand Rule (for straight conductors)

Answer 35

determines direction of magnetic field. Thumb - charge direction, Curled Fingers = magnetic field direction

Question 36

what does looping a current-carrying wire do

Answer 36

it increases the magnetic field

Question 37

solenoid

Answer 37

a coil of wire

Question 38

the shape of the magnetic field of a solenoid is

Answer 38

similar to that of a bar magnet

Question 39

more loops in a solenoid

Answer 39

increases field strength

Question 40

Second Hand Rule (for coils)

Answer 40

determines direction of magnetic field caused by a current-carrying coil. Curled Fingers = direction of current flow, Thumb = direction of North magnetic pole

Question 41

Third Hand Rule (for moving charges in magnetic field)

Answer 41

determines the direction of the force acting on a charged particle as it moves through an external magnetic field. Thumb = direction of charge motion, Fingers = magnetic field direction, Palm = direction of force on particle.

Question 42

What happens to neutral objects in electric or magnetic fields?

Answer 42

they are not deflected

Question 43

moving charges are known as

Answer 43

electric current

Question 44

what direction do electrons flow

Answer 44

from negative to positive

Question 45

if the conductor is levitated in the magnetic field

Answer 45

Fm = Fg

Question 46

What kind of force does magnetic force act like

Answer 46

centripetal force (center-seeking) (Fm=Fc)

Question 47

what is a mass spectrometer

Answer 47

a device that determines the charge to mass ratio of ions

Question 48

Generator effect (Induction)

Answer 48

a wire that is forced to move through a magnetic field produces a current. the current produced it's own magnetic field that opposes the original magnetic field.

Question 49

Galvanometer

Answer 49

device that measures current and it's direction

Question 50

Three ways to induce a current

Answer 50

1. Move a conductor near a magnet 2. Move a magnet near a conductor 3. change the strength of the magnetic field

Question 51

Lenz's Law

Answer 51

the direction of an induced current will cause a magnetic field that opposes the charge in the external field that is causing the induced current. uses conservation of energy.

Question 52

Motor effect

Answer 52

current carrying wire in a magnetic field will experience a force causing the wire to turn

Question 53

How do you tell which direction electric field lines are in?

Answer 53

the direction a positive charge would move (towards negative and away from positive)

Question 54

what is the net electric field?

Answer 54

the sum of all the individual fields

Question 55

magnetic fields are produced by

Answer 55

moving charges

Question 56

where does a compass needle point on a wire

Answer 56

it is deflected perpendicular to the current carrying wire. it shows the direction of the magnetic field

Question 57

the direction of the current flow affects the

Answer 57

direction of the magnetic field

Question 58

are electric and magnetic positive and negative the same phenomena

Answer 58

no. positive and negative charges are NOT attracted to or repelled from north and south poles