Electrical Systems

Question 1

What are electrical cells

Answer 1

Portable source of electricity

Question 2

Wat do electrical cells contain

Answer 2

Chemical Potential energy which is converted to electrical energy and then different types of energy

Question 3

What is an electrical circuit

Answer 3

Path along which electrical currents move, formed by electrical components joined together

Question 4

What is a closed circuit

Answer 4

Electrical components joined together without any gap creating a complete pathway for electrical current to flow through

Question 5

What is open circuit

Answer 5

Electrical components joined with a gap between creating incomplete path way for electrical current to flow

Question 6

What is an electrical current

Answer 6

Flow of electric charges

Question 7

How to measure electrical current

Answer 7

Ammeter

Question 8

How to connect ammeter to a circuit

Answer 8

Positive terminal of ammeter to positive terminal of the electrical cell

Question 9

How does conventional current flow + what does it carry

Answer 9

Charge carriers are positive charges

Flows from positive to negative end of terminal

Question 10

What is electron flow and what does it carry

Answer 10

Carries electrons

From negative to positive terminal of battery

Question 11

What is potential difference

Answer 11

Aka voltage

Amount of work done to drive a unit charge through the component

Question 12

How to measure potential difference

Answer 12

Using voltmeter

Question 13

How to connect voltmeter

Answer 13

Connect in parallel to appliance

Question 14

What is electrical resistance

Answer 14

Measurement of how much the component opposed the flow of electrical current

Question 15

SI unit of resistance and relationship

Answer 15

SI unit: ohm

The higher the electrical resistance, the harder it is for current to flow through causing current flow to be lower

Question 16

How does high/low resistance affect the bulb?

Answer 16

High resistance
Lesser current flow
Dull bulb

Lower resistance
More current flow
Bright bulb

Question 17

Do insulators and conductors have electrical resistance? [ tell me about special conductors too ]

Answer 17

Yes

Insulator like rubber plastic = vv high resistance = lesser current flow through

Conductor like copper = low resistance = more current flow through

TAKE NOTE: conductors like tungsten and in chrome are special and have vv high resistance

Question 18

What is a resistor

Answer 18

Electrical devices managing flow of current through circuit via controlling resistance in circuit

Question 19

What are fixed resistors

Answer 19

Resistor of known value which cannot be changed

Question 20

What are variable resistors

Answer 20

Aka rheostats

They vary the resistance in a circuit

Question 21

Tell me about the arrangement of one resistor in series

Answer 21

In series there is only one pathway for electrical current to flow through so one resistor in series will cause more hindrance and lesser current to flow through making bulb dimmer

Question 22

Tell me about the arrangement of two resistor in parallel

Answer 22

Parallel circuit have more than one pathway for electrical current to flow through causing lesser hindrance despite 2 resistors letting larger current flow through to shine the bulb brighter

Question 23

What is a series circuit

Answer 23

Circuit with only one pathway for electrical current to flow trough

If there is a gap circuit will be incomplete due to one pathway only causing circuit unit to become open

Question 24

What is a parallel circuit

Answer 24

It is a circuit it’s more than one pathway for current to flow through

Allows circuit to still be complete even if one bulb blows due to more than one pathway for electrical current to flow through

Question 25

What happens when a variable resistor slider is moved to the left

Answer 25

Lesser coils for electrical current to flow through | Lesser hindrance to occur | Larger electrical current flows through | Brighter appliance

Question 26

What happens when a variable resistor slider is moved to the right

Answer 26

More could for electrical current to flow through | More resistance and hindrance | Smaller electrical current flows through | Duller appliance

Question 27

What is a heating element

Answer 27

Something that can heat up rapidly when an electrical current passes through them

Question 28

Is nichrome a heating element?

Answer 28

Yes as it has high resistance and can withstand very high temperatures

Question 29

What is tungsten wire

Answer 29

Used insight bulbs due to high resistance and melting point of 2500.C

Question 30

What is damaged insulation and its impact

Answer 30

Insulating material that has been worn it causing conducting wires to be exposed Can cause electrical shocks

Question 31

Why are overheated cables bad and what are its 2 causes

Answer 31

Bad because it can cause electrical fires Caused by 1. Overloaded sockets causing unusually large currents to pass through them 2. Us of inappropriately thin wires

Question 32

Why does electricity love water?

Answer 32

Water contains impurities that create a conducting path for electrical current to flow through. It also has low resistance

Question 33

What are circuit breakers

Answer 33

1. Switch off electrical supply in a circuit when an unusually large current passes through circuit 2. Protects appliances form damage/fires 3. CONNECTED TO LIVE WIRE

Question 34

What are fuses?

Answer 34

Shor thin wire which cuts off electrical supply in a circuit when unusually large current threatens to pass but fuse needs to be replaced after it blows

Question 35

What rating should fuses be

Answer 35

Fuse rating should always be SLIGHTLY HIGHER THAN ELECTRICAL APPLIANCE

Question 36

Why cant fuse rating be equal to appliance rating

Answer 36

If appliance rating is 5 and fuse rating is 5 the electrical current being passed through the fuse is the maximum it can hold causing fuse to melt a little bit every time current passes before fully melting after a while and blowing

Question 37

Why cant fuse rating be too high?

Answer 37

It may cause really high current to flow through appliance even if appliance cannot handle it as the fuse can causing appliance to be damaged or fires to occur

Question 38

What is a live wire

Answer 38

Colour: brown Connected to high voltage and delivers current to appliance Fitted to fuse circuit breakers and switches

Question 39

What is a neutral wire

Answer 39

Colour: blue Completes circuit by providing return pathway for current It is always at *zero voltage*

Question 40

What are earth wires

Answer 40

Colour: blue and green Connected to metal casing of appliance to prevent user from shocks Low resistance Sends unusually large currents to the ground instead of person

Question 41

What is special about a three pin plug

Answer 41

- has a cartridge fuse to protect appliance during electrical fault - earth wire protects user from electrical shocks in event of electrical faults which turn appliance live

Question 42

What is special about double insulation

Answer 42

It has NO EARTH WIRE Double layer of insulating materials which protects conducting wires and users from electrical shocks

Question 43

What is the power of an appliance?

Answer 43

Amount of electrical energy used for conversion to other forms of energy per unit time

Question 44

SI unit of electricity

Answer 44

Watt 1000W = 1KW [ kilowatt ]

Question 45

How is using a more energy efficient appliance good?

Answer 45

More energy efficient = reduced electrical consumption