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AS - N927 Chem/Physics > 12 Electricity > Flashcards

Flashcards in 12 Electricity Deck (39)
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1

Current

Electron flow (I)
How much charge (how many electrons) pass through certain point in circuit per unit time
Quantity measured in Amperes
Body current = ion movement

2

Capacitance

Stored charge
Substance ability to store a charge

3

Inductance

How electricity generated

4

Ohm's Law

I = V / R
Analogous to Q = ΔP/R or BP = CO x SVR

5

Voltage

Electromotive force (EMF) or force that pushes electrons through resistance
Electrical charge potential difference directly proportional to electron flow (electric current)
Driving pressure P1 - P2
Measured in Volts

6

Resistance

Opposition force to electron flow
Flow inversely proportional to resistance
Measured in Ohms

7

Coulomb

Electric charge measure unit
1e¯ = 1.602 x 10^-19
1 Coulomb = 6.24 x 10^18 electrons
1 Coulomb e¯/sec = 1 Amp

8

Ampere

Ampere (Amp) measures current
1 Amp = charge movement carried by 6.24 x 10^18 electrons passing a certain point in 1 second
1 Amp = 1 Coulomb electric charge movement

9

I = V / R

Current = voltage/resistance
E = I x R
Electromotive force (E) = voltage
E = I x Z
Impedance (Z)

10

Impedance

Represented by Z
Resistance to current flow that changes w/ frequency
Power supply frequency at constant 60Hz
Impedance & resistance are interchangeable

High impedance = low current flow
Low impedance = high current flow

11

Watt

Power unit (work/time)
Joules/second
Electrical power measurement
W = V x I

12

Joule

Watt-second = work = energy
Work = mass x acceleration x distance
kg x m/s^2 x m or 1 Joule

13

Work

Force x distance (displacement)
Force = mass x acceleration
Measured in Joules

14

Energy

Kinetic = (mass x velocity^2) / 2
Potential = mass x 9.81m/s^2 x height

15

Power

Measured as Watts in electrical circuit
I x V

16

Conductor

Permits e¯ flow
Current = e¯ flow through conductor

17

Non-Conductors

Insulators
Tightly bound electrons that do not permit e¯ flow
Ex: glass, rubber, plastic, dry wood, pure water

18

DC

Direct current
e¯ flow always in the same direction
Ex: batteries

19

AC

Alternating current
e¯ flow reverses direction (oscillates) at regular intervals
Oscillating frequency measured in cycles per second (Hertz or Hz)
Ex: electric company

20

Capacitance

Substance ability to store a charge

21

Capacitor

Electrical device used to shore electric charge
Basic design - 2 parallel conducting plates separated by insulating layer called dielectric

22

Electromagnetic Field

Force field that consists both electric & magnetic components
Resulting from electric charge motion & containing definite amount electromagnetic energy
Electrons flow through wire induce a magnetic field around
When wire coiled repeatedly around an iron core → amplifies the magnetic field
Dual nature r/t electricity & magnetism
- Where there's an electric current there are also magnetic waves
- Where there are changing magnetic waves there's an electric current
Able to do work

23

Inductance

e¯ flow via wire induce magnetic field surrounding
When wire coiled repeatedly around an iron core this will increase the electromagnetic field to move e¯
Ex: wireless charging

24

Motor

Battery source
Metal bar w/ coiled wire
Fixed magnets
Opposing magnetic fields repel e¯ to rotate the metal bar

25

Generator

No power source
Fixed metal bar w/ coiled wire
EMF moves around wire → inductance
Magnets rotate to power light bulb

26

"Hot" Conductor

Carries the current through the impedance

27

"Neutral" Conductor

Return the current to the source

28

Shock Hazards

Contact external electricity source
AC or DC current
Source - when person becomes part or completes an electric circuit; must contact the electric circuit at 2 points and there must be voltage source causing current to flow

29

Electricity Damage

Current disrupts normal cell electrical function
Or current passing through resistance (body) increases the temperature and can produce a burn
Severity depends on amount of current (Amperes) & contact duration

30

Macroshock

Large amount current
100-300mA V fib