Chapter 13 Flashcards

(68 cards)

1
Q

What forms a electrical system?

A

electrical appliances + electrical components

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2
Q

What is a cell and what does it do?

A

what: one battery
do: provide energy to push electric charges around circuit

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3
Q

What does an ammeter measure?

A

measure electric current

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4
Q

What does an voltmeter measure?

A

measure voltage

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5
Q

What does variable resistor (rheostat) do?

A

reduce electric current, increases electric resistance

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6
Q

What is electric current and SI unit?

A
  • It is the rate of flow of electric charges
  • SI unit: ampere (A)

rate- per unit time

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7
Q

When does electricity flow?

A

When there is
- source of electrical energy (battery)
- closed circuit

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8
Q

How does flow of electrical charges affect current?

A

greater flow of electric charges per unit time, larger current

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9
Q

Symbol VS unit of electric current

A

I- is symbol of electric current
A- unit of electric current

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10
Q

Which direction is convection current?

A

Current starting from the positive terminal of the battery and ending at negative terminal of battery (unlike charges attract)

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11
Q

Which direction is electron flow?

A

Starts at negative terminal to ending at positive terminal

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12
Q

How is electric current measured?

A

with ammeter

red- positive black-negative

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13
Q

How is a ammeter connected?

A

IN SERIES (single electrical path thus, same current passing)

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14
Q

What is a series circuit?
3 POINTS

A
  • A single path
  • Current - same
  • One bulb removed, no current flows
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15
Q

What is a parallel circuit?
4 POINTS

A
  • Two/more branches - electrical component in each branch
  • Current- divides and flows through each branch
  • One bulb removed, others remain lit (circuit remains closed)
  • sum of electric current at individual branch equals to total current in circuit
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16
Q

What is electrical conductors?

A

Low resistance to current

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17
Q

What is electrical resistance?

A

ability to slow/oppose current

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18
Q

What is electrical insulators?

A

current cannot flow through (VERY HIGH RESISTANCE)

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19
Q

What is electrical energy converted to?

A

thermal + light energy

any electrical components with resistance will be able to convert electrical potential energy to

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20
Q

What has little to no resistance?
2 POINTS

A
  • ammeter
  • connecting wires

NO convertion of energy when current flows through

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21
Q

Definition 1 and SI unit of potential difference

A
  • work done to drive unit electric charge through the component
  • in simple terms, measurement of the difference in electric energy between two points in a circuit
  • SL unit: voltage (V)
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22
Q

How is a voltmeter connected?

A
  • ONLY IN PARALLEL across bulb (connected in series- no current in the circuit due to its high resistance)
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23
Q

What is work done?

A

process of energy transfer

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24
Q

How is the battery supplied?
(energy conversion)

A

chemical potential energy to electrical potential energy

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25
Potential difference/voltage 2 definition
amount of electrical potential energy that is converted to other forms of energy WHEN electric charges passes through the component
26
Difference between potential/potential difference
**potential**- electrical potential energy that is available to every unit of electrical charge **potential difference** - difference between electrical potential energy when the same unit charge passes through the bulb
27
What does the voltmeter show?
difference in the potential values (HP- LP) | HP - high potential LP -low potential
28
What is the law of conservation of energy?
the difference/decrease in electrical potential energy- amt of energy converted to thermal energy when unit electric charge passes through
29
Whay is an electrical component?
- an obstacle against flow of electrons :( - have resistance
30
How does the resistance affect the current? (relationship)
higher resistance, lower current
31
How is electrical resistance produced?
- As electrons move through the conductor, - they collide with metal ions which are vibrating abt their fixed positions. - these collisions opposes flow of electrons - hence, resistance is produced
32
What is the definition of resistance? (formula as well)
- ratio of voltage across the component to the current flowing through it R=V/I
33
How does the temperature affect the resistance?
higher temperature, higher resistance
34
YOU ARE DOING GREAT
DUH YES
35
What is a resistor/rheostat? 4 POINTS
- conductor that has high resistance - used in circuit to control amount of current - different values of resistances-change settings (move slider along metal rod- change length of wire which current flows) - fixed OR variable ## Footnote current flow through longer length, greater electrical resistance, lower current
36
Use of variable resistor
Thermometer
37
Resistor added in series. Calculate total resistance
- Rt= R1+R2+R3+R4... - increases overall resistance
38
Resistor added in parallel. Calculate total resistance
- 1/Rt = 1/R1 + 1/R2 = 2/R (THEREFORE Rt= R/2 **FLIP!**) - decreases overall resistance
39
What happens when electrical energy is passed through certain chemical solution/liquid?
Chemical change occurs
40
What is the chemical effect of electric current used for?
- Used in extraction of metals - For electroplating an object with a thin layer of metal
41
What is electroplating?
- Repeated cleaning/disinfection of surgical instruments (increase rate of corrosion)
42
What do antimicrobial properties do? (gold and silver contain)
- Destroy harmful microorganisms
42
Why is electroplating useful?
- It minimize damage/lengthen lifespan- clean/safe to use
42
What happens when electrical energy is passed through a heating element?
Electrical energy is converted to thermal energy and sometimes light energy
42
How does a heating element work?
- consists of wire made of high resistance material, that is able to withstand high temperatures ## Footnote nichrome wire, becomes hot when a current flows through
42
What direction does the compass face when there is no current flowing?
North
43
What direction does the compass face when there is current flowing through?
In the direction of the current's magnetic field.
44
When electric charges move what is produced?
There will be magnetic field produced
45
What happens when electric current passes through a magnetic element?
Electromagnet is formed (temporary magnet)
45
How do you increase the strength of electromagnets?
- Increase current-increase battery - Increase number of turns of coils
45
Define power and SI unit :) | **KEEP GOING YOU CAN DO IT! <3
- rate of work done - SI unit: Watts (W) | Rate- per unit time
46
Define work done :)
- energy transfer per unit time
46
SI unit of energy
- Joules (J) - kWh (used to measure electricity in homes)
47
Formula for energy
E= Pt | energy (kWh), power(kWh) and time(H)
48
How do you reduce the consumption of electricity? (common sense :l)
- turn off appliances when not in use - use LED lamp instead of other :)
49
When does electric fire occur?
- large current flows in electric wiring and wire get too hot
50
What is the two main electrical danger?
- electric shock - electric fire
51
When does electric shock occur?
- when a person touches damaged/exposed wire carrying current
52
Can water conduct electricity?
Yes although it is not a good conductor
53
How are frayed and damaged wires formed?
Short circuit- a large current- wires become hot- electric fire when someone touches it- electric shock
53
What is a short circuit?
- A path with very low resistance between two points in a circuit
53
When does overloading occur?
- too many electrical appliances are connected to a main socket (using an electrical adaptor)
54
When does a short circuit occur?
- broken/bare wire touches another wire
55
Why is overloading dangerous?
- a large current flows in the house- causes wire to be too hot - cause fire >:( mom mad >^<
56
Define fuse and use of it :) (go on bbg!)
- fuse is an electric component - protect the electric appliances from overheating due to excessive current.
56
How does circuit breaker work?
- current flow- too large- switch linked to electrical trips and cuts off current- prevent electric shocks
57
2 safety devices in household electrical system
- Fuse - Circuit breaker
58
How does fuse work?
- Due to electrical fault in an appliance, current flows-larger than current rating of its fuse - causes- fuse-melt - fuse- melts- no current can flow - NEED TO REPLACE FUSE IF THAT HAPPENS :)