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grade 9 all science notes > Current electricity > Flashcards

Current electricity Flashcards

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1
Q

current electricity

A

controlled flow of electrons through a conductor
a steady flow between two objects
used to power devices

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2
Q

electric circuit

A

continuous path where electrons can flow

includes: energy source, load, wires, sometimes a switch

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3
Q

energy source

A

could be small and portable like a battery

or large like a generating station

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4
Q

load

A

something on a circuit that converts electrical energy to another form of energy
ex: lightbulb= electrical energy- light energy

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5
Q

switch

A

controls the flow of the electrons by opening or closing the path

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6
Q

wires

A

joins all parts together creating a pathway that has to be full circle
copper/ aluminum,

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7
Q

electrical energy

A

energy provided by the flow of electrons in a circuit
measured in joules
makes devised work

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8
Q

sources of electrical energy

A

can be a better which gives small amounts or

electric generating systems which gives large amounts from wires to your home

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9
Q

electric cells

A

a device that converts chemical energy to electrical energy and is portable
is consists of two electrodes (a negative and a positive)
and a electrolyte that is the source for electrons
the electrons leave the negative side (repelled) and go in the positive side (attract)

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10
Q

primary cells

A

electric cell that can only be used once because the chemical reactions they produce cannot be reversible
they cannot recharge

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11
Q

secondary cells

A

electric cells that can be recharged and used multiple times
like how you can recharge batteries
and reverse the chemical reactions

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12
Q

fuel cells

A

kind of electric cell where a continuous supply of chemicals is pumped as the cell operates
waste products are removed
and they can operate longer

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13
Q

direct current

A

flow of electrons in one direction around the circuit
produced by a cell
powers portable electric devices

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14
Q

alternating current

A

flow of electrons alternates direction in a electric circuit, goes back and forth
works in a generator not a cell
distributing energy over long distances

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15
Q

generating electricity

A

electrical generator takes energy produced by a non electrical source and converts it to electrical energy
uses one type of energy to make another

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16
Q

how does a generator work

A

external evergy– turns turbine– turns a coil witha magnet on it– send electrons up the coil– electricity– wires–homes

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17
Q

sir Micheal Faraday

A

invented the generator

providing a constant flow of electrons

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18
Q

generating current energy

A

to run a current you need elecctrical energy which uses generators
generators need a external energy source
can be moving water steam or wind

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19
Q

moving water
pro
con

A 
hydroelectric generation 
-falling water turns the turbines 
- comes from rivers, lakes, waterfalls, dams 
-180 in Canada 
PRO- no air or water pollution 
CON- (dams) changes the ecology of a area 
migration of fish is disrupted 
flooding 
expensive, money for taxpayers
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20
Q

tidal generation

A

uses moving water- tidal energy= energy from moving ocean water to turn turbines
twice a day
renewable

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21
Q

thermal generation

A

heating water to produce steam

steam turns turbines

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22
Q

fossil fuels- steam

A

it is energy stored in dead cells
can be burned to create steam non renewable
OLD WAY coal= pollution, CO2 heats up the earth, mercury, acid precipitation, smog
NEW WAY gas= cleaner less C02 not a lot left

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23
Q

radioactive materials= steam

A

uranium is put in a reactor and when the nucleus collide with uranium it creates nuclear fission
the nucleus break creating energy to heat water to create steam
non renewable
must be mined creating pollution and habitat loss
puts high temperature water back in lakes
radioactive waste can cause cancer
expensive/ dangerous

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24
Q

biomass=steam

A

using biological material to to burned to cream steam
renewable
may not be enough for the energy we need

25
Q

geothermal energy

A

taking energy from deep i n the earths crust and bringing it up with pipes to be burned to create steam
renewable
no pollution
hard to get and expensive to build

26
Q

wind

A

use a wind turbine connected to a generator
maintenance costs are cheaper
wind is free
turbines can be closer to homes with less wires
no pollution

27
Q

light

A

device can convert light into electrical energy
ex sun
PRO renewable, no pollution, lasts a lot of years
CON little pollution, only 30% effective, expensive, not immediate

28
Q

electrical power

A

rate at which electrical energy is produced

measured in Watts (iW=1j/second)

29
Q

killowatt hour

A

unit measures energy usage

1000 times more than a Watt hour

30
Q

efficiency

A

comparison of output vs input in a percentage

31
Q

cost

A

wattage/1000= KWh x hours used in one day x price x days used

32
Q

power

A

voltage x current

33
Q

wires into house

A

BLACK- hot 120v in and out
RED- hot 120v in and out
WHITE- neutral to the ground

34
Q

service panel

A

breaker box with all the wires inside it with a total voltage of 240
electricity goes through it

35
Q

circuit breaker def

A

connects all series circuits in one spot

has many switches

36
Q

neutral wire

A

goes to the ground to protect from electrocution

the small hole at the bottom on the plug

37
Q

3 prong plugs

A

has 3 areas for the electricity to go

one goes to ground to stop death

38
Q

how circuit breakers help

A

opens the circuit if the current is too high
so that it doesn’t explode or cause a fire it just stops
reusable usually 15 amps

39
Q

fuses

A

same as circuit breakers just not reusable

40
Q

ground fault circuit interpreter

A

detects problems with the ground wire and if its too much it turns off the breaker
used near water

41
Q

polarized plugs

A

the fact that plugs have different sizes to make it so energy can only flow through one
it reduces the risk of shock

42
Q

resistance

A

the flow of current measured in Ohms
when the voltage is high it means the current is also high
volts/ ampere
the total resistance of a circuit is the sum of the resistance of all the load

43
Q

current

A

the measure of that flow rate of electric charge in a circuit
the current is the same at all points in the circuit
uses an ampere to find out the current
the symbol is I
measured in amperes
the unit symbol is A or coulombs/second

44
Q

voltage

A

also called potential difference
measured the difference in electrical potential energy between two points in a circuit
has to be in parallel to what it is measuring
measured in voltage
the voltage of a battery would be a measure of how much force it gives the current

45
Q

_______________

A

wire symbol

46
Q

____!________

j !

A

connected wire (dot)

47
Q

_______/_______

/

A

not connected wire (no dot)

48
Q

’/

A

cell

49
Q

’/’/

A

battery

50
Q

ammeter

A

a A with a circle around it

51
Q

/]/]/]/]/]/

A

resistor

52
Q

./ .

A

open switch

53
Q

_.__.__

A

closed switch

54
Q

light bulb

A

circle with an X or a cursive e

55
Q

motor

A

circle with an M

56
Q

series circuit

A

there is only one path for the electrons to flow and all the loads are connected in that circuit

57
Q

parallel

A

a circuit with more than one pathway for the electrons to flow
loads can be on different paths

58
Q

Charge

A

Measured in coulombs
Q is the symbol
the amount of power emitted

59
Q

Ohms law

A

formula. that says that
resistor’s current =resistor’s voltage/ resistance
which shows the voltage drop of the resistor,

grade 9 all science notes (8 decks)

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