Electricity -Terms and definitions Flashcards Preview

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Flashcards in Electricity -Terms and definitions Deck (97):
1

I=V/R

I = current (A)
(V) = voltage (v)
R = resistance

Ohm's law!

2

Voltage and Wattage

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

Ohm's Law

The current in a circuit on an electrical component, depends on the voltage and resistance.

4

Voltage in a series circuit

In a series circuit, voltage SPLITS

5

Power

Symbol: P
Unit: Watt (w) or J.s^-1
Power measures how fast energy is transformed (work done).

6

Centripetal Force & Magnetic Field

Fc = F
Fc = (mv^2)/r
F = Bqv
thus
(mv^2)/r = Bqv

7

Electrical Field Strength

Symbol: E
Unit: NxC-1

8

Electrical Charge

Symbol: q
Unit: Coulomb (c)

9

Resistance

Symbol: R
Unit: Ohm Ω
Resistance is the ability of an electrical component to OPPOSE THE FLOW OF AN ELECTRICAL CURRENT

10

F=BIL

F = force (N)
B = Magnetic Field Strength (T)
I = Current (A)
L = effectuve (perpendicular) distance of wire cutting the magnetic field.

11

Conventional Current

Always goes from positive to negative.
In reality, it is actually negative electrons going from negative to positive.

12

Resistors in series

Rtotal = R1 + R2 + R3...

13

P = *E/t

P = power (w)
*E = Change in energy (J)
t = time (s)

14

V = BLv

V = Voltage (v)
B = Mgnetic Field Strength (T)
L = Length (m)
v = Velocity (m/s)

15

dot -Magnetic field

Going out of the page

16

Force on Moving Charge in Magnetic Field

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

Lenz Law

The direction of this current/voltage will be such that it will create a force to work against the movement.

18

Parallel circuit

When there is more than 1 pathway for electricity to go through

19

F = Bqv

F = Force (N)
B = Magnetic Field Strength (T)
q = charge (c)
v = velocity (m/s)

20

v=*E/q (*=change in)

v = Voltage
*E = Energy (gained or lost) (J)
q = charge (c)

21

Current in a Parallel Circuit

In a parallel circuit, the current SPLITS

22

Charge

symbol: q
units: coulomb (c)
def

23

F=E.q

F = force (N)
E = Electrical Field Strength (N.C^-1)
q = charge (c)

24

Current in a series circuit

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