Electricity -Terms and definitions Flashcards
1
Q
I=V/R
A
I = current (A) (V) = voltage (v) R = resistance
Ohm’s law!
2
Q
Voltage and Wattage
A
If an electrical appliance says “220v, 45w” on it, this means that when it’s connected to a voltage of 220v, the power is 45w.
3
Q
Ohm’s Law
A
The current in a circuit on an electrical component, depends on the voltage and resistance.
4
Q
Voltage in a series circuit
A
In a series circuit, voltage SPLITS
5
Q
Power
A
Symbol: P
Unit: Watt (w) or J.s^-1
Power measures how fast energy is transformed (work done).
6
Q
Centripetal Force & Magnetic Field
A
Fc = F Fc = (mv^2)/r F = Bqv thus (mv^2)/r = Bqv
7
Q
Electrical Field Strength
A
Symbol: E
Unit: NxC-1
8
Q
Electrical Charge
A
Symbol: q
Unit: Coulomb (c)
9
Q
Resistance
A
Symbol: R
Unit: Ohm Ω
Resistance is the ability of an electrical component to OPPOSE THE FLOW OF AN ELECTRICAL CURRENT
10
Q
F=BIL
A
F = force (N) B = Magnetic Field Strength (T) I = Current (A) L = effectuve (perpendicular) distance of wire cutting the magnetic field.
11
Q
Conventional Current
A
Always goes from positive to negative.
In reality, it is actually negative electrons going from negative to positive.
12
Q
Resistors in series
A
Rtotal = R1 + R2 + R3…
13
Q
P = *E/t
A
P = power (w) *E = Change in energy (J) t = time (s)
14
Q
V = BLv
A
V = Voltage (v) B = Mgnetic Field Strength (T) L = Length (m) v = Velocity (m/s)
15
Q
dot -Magnetic field
A
Going out of the page
16
Q
Force on Moving Charge in Magnetic Field
A
A charged particle moving inside a magnetic field will experience a force. Use right-hand slap rule.
Force will cause the particle to turn (centripetal force).
Force and Velocity are always at 90°.
NOTE: If charge is negative, thumb should point in opposite direction due to conventional current.
17
Q
Lenz Law
A
The direction of this current/voltage will be such that it will create a force to work against the movement.
18
Q
Parallel circuit
A
When there is more than 1 pathway for electricity to go through
19
Q
F = Bqv
A
F = Force (N) B = Magnetic Field Strength (T) q = charge (c) v = velocity (m/s)
20
Q
v=E/q (=change in)
A
v = Voltage *E = Energy (gained or lost) (J) q = charge (c)
21
Q
Current in a Parallel Circuit
A
In a parallel circuit, the current SPLITS
22
Q
Charge
A
symbol: q
units: coulomb (c)
def
23
Q
F=E.q
A
F = force (N) E = Electrical Field Strength (N.C^-1) q = charge (c)
24
Q
Current in a series circuit
A
In a series circuit, current STAYS THE SAME
25
B = (KI)/d
```
B = Magnetic field strength (T)
I = current (A)
d = distance to current (m)
k = constant number: 2.0x10^-2T.M.A
```
26
Voltage
symbol: V
Is also called the 'potential difference'.
It is the amount of electrical potential energy one coulomb of charge gains or losses across an electrical current.
27
Magnetic Field
Has two poles (North and South). Magnetic field lines travel from NORTH to SOUTH
The lines do not cross eachother
```
Magnetic field strength is represented by the lines.
Small gaps (tight spacing)= strong magnetic field
Large gaps (lose spacing)= weak magnetic field
```
Symbol: B
Unit: T (Tesla)
28
Ammeter
Symbol: A
An ammeter has zero resistance
Because of this, the ammeter goes within the circuit, not attached in parallel.
29
Electromagnet
A solenoid (densely wounded coil of wire) that creates a magnetic field when current is added. Sometimes an iron core is added to strengthen the magnetic field.
30
Series Circuit
When there is only one pathway for electricity to go through
31
P = VI
```
P = Power (w)
V = voltage (v)
I = current (A)
```
32
Current
Symbol: I
| Is how many coulombs of charge pass through a point in 1 second.
33
Voltmeter
Symbol: v
A voltmeter has infinite resistance
Because of this, the voltmeter must go parallel to the circuit, not within it.
34
Positive Charge
In direction of force
35
Negative Charge
Opposite direction of force
36
Resistors in parallel
1/Rtotal = 1/R1 + 1/R2 + 1/R3 ...
37
Faraday's Law
When a wire is moving through a magnetic field, a voltage/current will be induced
38
X -Magnetic field
Going into the page
39
Right-hand slap rule
Thumb: Direction of current
Four Fingers: Direction of magnetic field
Palm (slap): Direction of the force
40
Ep=Eqd
```
Ep = Electrical potential energy (J)
E = Electrical field strength (N.C^-1)
q = charge (c)
d = distance (m)
```
41
P=VI
```
P = power (w)
V = Voltage (v)
I = Current (A)
```
42
E=V/D
```
E = Electrical Field Strength (N.C^-1)
V = voltage (v)
d = distance between two plates (m)
```
43
Voltage in a parallel circuit
In a parallel circuit, the voltage STAYS THE SAME
44
Power
Power measures how fast energy is transformed (work done).
Symbol: P
Unit: Watt (W) or J/s
-The brightness of a lamp is dependant on its power. Bigger power = brighter lamp.
-The heat of a heater dependant on power.
Bigger power = heat up faster.
45
Right-hand Grab Rule
(To find the direction of the magnetic field around a wire/coil)
1. Thumb = direction of current
2. 4 fingers = curl in the direction of the magnetic field lines
3. GRAB
46
P=ΔE/t
```
P = Power (W)
ΔE = Change in energy (J)
t = time (s)
1W = 1 J/s
```
47
Faraday's Law
When a wire is moving through a magnetic field, a voltage/current will be induced.
48
Lenz Law
The direction of this current/voltage will be such that it will create a force to work against the movement.
49
V=BLv
```
V = Voltage (v)
B = Magnetic Field Strength (T)
L = Length (cm)
v = velocity (m/s)
```
50
Attraction of Electric Charges
Unlike charges give negative potential energy (attractive force). uUnlike charges attract one another.
51
Charging by Conduction
Charging an object by allowing it to come into contact with an object that already has an electrical charge.
52
Charging by Friction
Two objects rub together and one becomes positivley charged and the other becomes negativley charged
53
Charging by Induction
Charging and object without direct contact (proximity to nearby object charges neutral object)
54
Conductors
Materials that allow electric charges to flow through them easily
55
Coulomb
Unit used to measure quantity of electric charge
56
Current
A flow of electric through a conductor
57
Current Electricity
The continuous flow of electrons through a conductor
58
Direct current
An electrical current that always moves in one direction
59
Electric circuit
Consists of a voltage source and a continuous conducting path for a current to follow
60
Electric current
The flow of electric charge electric field force field produced by an electrical charge
61
Electrical Field
The field around charged particles that exerts a force on other charged particles
62
Electrical Field lines
A map of an electric field representing the direction of the force that a positive charge would experience
63
Electric flux
The product of a surface area and the component of the electric field perpendicular to the surface
64
Electric generator
A mechanical device that uses wire loops rotating in a magnetic field to generate electricity
65
Electric Potential
The difference in electrical charge between two points in a circuit expressed in volts (aka potential difference)
66
Electrical potential energy
Potential energy due to the position of charge near or other charges
67
Electrical conductors
Materials that have electrons that are free to move throughout the material; for example, metals
68
Electrical energy
A form of energy from electromagnetic interactions
69
Electrical Force
A fundamental force that results from the interaction of electrical charge
70
Electrical insulators
Electrical nonconductors, or materials that obstruct the flow of electric current
71
Electrical resistance
The property of opposing or reducing electric current
72
Electrolyte
Water solution of ionic substances that conducts an electric current
73
Electromagnet
A magnet formed by a solenoid that can be turned on and off by turning the current on and off
74
Electromagnetic force
One of four fundamental forces; the force of attraction or repulsion between two charge particles
75
Electromagnetic induction
Process in which current is induced by moving a loop of wire in a magnetic field or by changing the magnetic field
76
Electron current
Opposite to conventional current; electron current flows from the negative terminal to the positive terminal
77
Electrostatic charge
An accumulated electric charge on an object from a surplus or deficiency of electrons
78
Magnetic Dipole
Magnet with two poles (North & South); all magnets are dipoles; cutting one in half creates two dipoles
79
Magnetic Field Lines
Invisible lines that map out the magnetic field around a magnet
80
Magnetic Flux
The lines of force surrounding a permanent magnet or moving charged particle
81
Magnetic Forces
Forces that may attract or repel without touching
82
Ferromagnetic Materials
Iron, cobalt, nickel
83
Magnetic Poles
The ends, or sides, of a magnet about which the force of magnetic attraction seems to be concentrated
84
Magnetic Reversal
The flipping of polarity of the earth's magnetic field
85
Magnetism
The force of repulsion (pushing) or attraction (pulling) between poles of magnets
86
Negative electric charge
One of the two types of electric charge; repels other negative charges and attracts positive charges
87
Ohm
Unit of resistance equivalent to volts/amps
88
Ohm's Law
The lat that states that resistance is equal to voltage divided by current (R=VI)
89
Positive Electric charge
One of the two types of electric charge; repels other positive charges and attracts negative charges
90
Power
The rate of doing work is called power
91
Power dissipated by a Resistor
P=IV=I^2R=V^2/R
92
Repulsion of Electric Charges
Like charges give positive potential energy (repulsive force). Like charges repel one another.
93
Resistance
A material's opposition to the flow of electric current, measured in ohms
94
Resistors
Objects that allow charge to flow at a reduced rate (change into heat or light)
95
Solenoid
A cylindrical coil of wire that becomes electromagnetic when a current runs through it
96
Superconductors
Some materials in which, under certain conditions, the electrical resistance approaches zero
97
Voltage drop
The electrical potential difference across a resistor or other part of a circuit that consumes power
