Electricity and Magnetism Flashcards
1
Q
Anything that occupies space and has mass
A
Matter
2
Q
no two things can occupy the same space at the same time
A
Law of Impenetrability
3
Q
a substance which cannot be reduced to a simpler substance by chemical means
A
Element
4
Q
a substance that resulted when two or more elements chemically combine
A
Compound
5
Q
a combination of non-chemically combined elements, can be separated through physical means
A
Mixture
6
Q
smallest particle of an element that retains the characteristics of that element
A
Atom
7
Q
composed of neutron and proton
A
nucleus
8
Q
another name for proton and neutron
A
nucleon
9
Q
charge of an up quark
A
+2/3
10
Q
charge of a down quark
A
-1/3
11
Q
what is the quark composition of proton?
A
2 Up
1 Down
12
Q
what is the quark composition of electron?
A
3 Down
13
Q
a chemical combination of two or more atoms. smallest unit of a compound
A
molecule
14
Q
process by which an atom loses or gains an electron
A
Ionization
15
Q
an atom that gained an electron
A
anion
16
Q
an atom that lost an electron
A
cation
17
Q
an electron removed from its valence shell due to the application of ionization energy
A
free electron
18
Q
what are the classifications of materials based on electrical conductivity
A
conductor, semiconductor, insulator
19
Q
what is in between the conduction and valence band?
A
forbidden band, band gap, energy gap
20
Q
energy gap of conductors?
A
0eV
21
Q
energy gap of semiconductors?
A
1eV
22
Q
energy gap of insulators?
A
5eV
23
Q
what is the conduction band?
A
the energy range that allows electron to roam freely within the material
24
Q
what is the valence band?
A
the energy band where electrons do not have enough energy to detach and roam freely
25
what is the band gap?
the energy that an electron needs to detach itself from the atom to roam freely
from valence to conduction
26
how can a good conductor conduct current?
by having a single valence electron, since they only have a single valence electron, the energy needed to create a "flow" is small
27
a good semiconductor has how many valence electrons?
4 valence electrons
28
how can a good insulator prevent the flow of electrons?
insulators are materials that are almost stable, they have 7 valence electrons, 1 electron away from a stable valence of 8. This 7 makes them reactive, but since there are 7 valence electrons, more energy is required to start a flow with these materials as the medium.
they can still conduct, but at higher energies
29
refers to a set of physical phenomena that is associated with the presence of electric charge
Electricity
30
deals with phenomenon caused by the attraction and repulsion of stationary charge
Electrostatic
31
First law of Electrostatics
opposite charges attract, while similar charges repel each other
32
Second law of Electrostatics
Coulomb's First Law - Electrostatic Force is directly proportional to Q1 and Q2
Coulomb's Second Law - Electrostatic Force is inversely proportional to the square of the distance between the 2 charges
33
SI and CGS unit of Electrostatic Force
SI: Newton
CGS: Dyne
34
Newton to Dyne conversion
1N = 1x10^5 dynes
35
Charge to Electrostatic Unit
1C = 3x10^9 ESU
36
Force per unit of positive charge
can be felt by a stationary charge in a given location within the field
Electric field
37
units of electric field
V/m, F/c, J/cm
38
due to the ionization of an electron which has an unpredictable path
Random drift
39
direction of migration of a free electron due to the potential difference
Directed Drift
40
types of contact electrification
Frictional electrification (triboelectric effect), conduction electrification, induction electrification
41
a type of contact electrification where some materials become electrically charged after they come into contact with another material through friction
frictional electrification or triboelectric effect
42
electric charge on a material's surface due to friction
static charge
43
body can store ______ volts as you walk across a carpet
30,000
44
resistance of resistors decreases as the frequency increases due to parasitic capacitances
Boella effect
45
increase in resistance as frequency increases due to the ac current congested on the conductor's surface
Skin effect
46
expulsion of magnetic fields from superconductors as they are cooled down below a critical point
Meissner effect
47
any directional movement of electric charges
Electric current
48
energy needed to move a charge
Potential Difference
49
current flowing through an area
Current Density
50
property of a material to oppose or limit the flow of current or charge
Resistance
51
factors that affect resistance
- resistivity
- length
- area
- temperature
52
in conductors, resistance increases, when temperature _______. why?
increases, positive thermal coefficient
directly proportional
resistance increase as temp increases
53
in semiconductors, resistance increases, when temperature _______. why?
decreases, negative thermal coefficient
indirectly proportional
resistance decrease as temperature increases
54
room temperature in electronics
25 degrees Celsius
55
best conductor
silver
56
number-size relation ship in american wire gauge standard
lower the number, higher the cross sectional area
57
ohm's law states that?
current is directly proportional to the voltage and inversely proportional to the resistance
58
ability of a system to store energy through electric fields
capacitance
59
ability of a system to store energy through magnetic field
inductance
60
property of an electrical circuit to resist the change in voltage?
capacitance
61
property of an electrical circuit to resist the change in current?
inductance
62
reciprocal of capacitance? unit?
electance, daraf
63
composed of two parallel plates with a dielectric in between
capacitor
64
composed of wires coiled around a core like a solenoid
inductor
65
factors that affect inductance?
number of turns
number of coil winding layers
permeability
length
cross sectional area
66
property shared by neighboring inductors that either increases or decreases the total inductance of a circuit (inductors in a series)
mutual induction
67
induced current is always _______ with the inducing current
opposite
68
another name for induced current?
Eddy current
69
phenomenon whereby a substance attracts pieces of iron
magnetism
70
SI and CGS units of magnetomotive force
Ampere-turn
Gilberts
71
SI and CGS units of magnetic field intensity
Ampere-turn per meter
Oersted
72
SI and CGS units of magnetic flux
Weber
Maxwell
73
SI and CGS units of magnetic flux density or magnetic field
Tesla
Gauss
74
lagging effect in a material's magnetic field and the magnetizing force that induced the magnetic field?
Hysteresis
75
measure of the resistance of a ferromagnetic material to becoming demagnetized
Coercivity
76
a measure of a material's ability to retain a certain level of magnetization after an external magnetic field is removed
Retentivity
77
78
ability of a material to allow magnetic flux to flow through it
permeability
79
ability of a material to allow electric field to flow through it
permittivity
80
ability of a material to resist the flow of magnetic flux
reluctance
81
types of magnetic materiala?
ferromagnetic
paramagnetic
diamagnetic
82
type of magnetic material whose relative permeability is much greater than 1
ferromagnetic material
83
type of magnetic material that has a weak magnetic attraction, relative permeability is slightly greater than 1
paramagnetic material
84
type of magnetic material that has no net magnetic moment, permeability is slightly less than 1
diamagnetic material
85
non-metals that exhibit magnetic properties
ferrimagnetic material
86
field that focuses on the relationship between electricity and magnetism
electromagnetism
87
faraday's first law?
emf is induced whenever the magnetic field changes
88
faraday's second law?
emf in a coil is equal to the negative rate of change of the magnetic flux through the coil, multiplied by the number of turns (N) in the coil
89
law which states that the induced current is always opposite of the inducing current
Lenz' Law
