Year 11 topic - electricity

Question 1

what is electrical current

Answer 1

the flow of electrical charge

Question 2

what is current measured in?

Answer 2

amps

Question 3

what is electric charge measured in?

Answer 3

coloumbs

Question 4

what is resistance

Answer 4

the measure of how it resists the flow of charge

Question 5

what is resistance measured in

Answer 5

ohms

Question 6

what is potential difference

Answer 6

the difference in electrical potential from one point in a circuit to another

Question 7

what is voltage measured in

Answer 7

volts

Question 8

what is the equation for potential difference

Answer 8

V=IR

Question 9

equations for charge

Answer 9

Q=It (charge = current x time)

Question 10

equation for power in circuits

Answer 10

power = potential difference x current

Question 11

What does an IV graph look like for a resisitor

Answer 11

a straight line through 0,0

Question 12

Whats the iv graph for a filament bulb

Answer 12

increases but curves (like an s shape)

Question 13

whats the iv graph for a diode

Answer 13

up at one point but then 0 for the rest (only lets electric flow one way)

Question 14

What is static charge

Answer 14

When insulating materials such as cloth and plastic are rubbed against eachother and the mats become electrically charged

Question 15

What particles are moved by the friction from one material to the other

Answer 15

Electrons

Question 16

How does an electric shock occur

Answer 16

When charge increases so does potential energy up to point a spark can jump across a gap to any conductor near

Question 17

Properties of an electrostatic force

Answer 17

Non contact force, forces of attraction and repulsion

Question 18

What kind are represented by the arrows

Answer 18

Positively charged ions

Question 19

What do the closeness of the arrows represent

Answer 19

The amount of charge

Question 20

Current and voltage rules for series circuits

Answer 20

Current = same everywhere 
Voltage = shared between components

Question 21

Voltage and current in a parallel

Answer 21

Current = splits on each path
Voltage = same on every path

Question 22

How to get positive and negative values on an IV graph

Answer 22

Switch citecuit wires around as that changes direction of the current

Question 23

Explain a direct current

Answer 23

Potential diff= always pos or negative

Current supplied by cells in batteries

Question 24

Explain an alternating current

Answer 24

Potential diff= alternates between negative and positive current also alternates
Current used in mains electricity

Question 25

What does mains electricity use

Answer 25

Three core cable

Question 26

Name the three wires in the three core cable

Answer 26

Live wire, neutral wire and earth wire

Question 27

What colours are each wire from the three core cable

Answer 27

Earth = green Neutral = blue Live wire = brown

Question 28

What potential difference is mains electricity in the UK

Answer 28

230V

Question 29

Each wire of the mains electricity carries a different __________ potential

Answer 29

Electrical

Question 30

What happens to the resistance of a thermistor as the temp increases

Answer 30

Resistance decreases

Question 31

What happens t the resistance of a Light dependant resistor as light intensity increases

Answer 31

Resistance drecreases

Question 32

What type of current is supplied by cells and batteries

Answer 32

A direct current

Question 33

What current is used in mains electricity

Answer 33

Alternating current

Question 34

What does the neutral wire do

Answer 34

Completes the circuit

Question 35

What does the live wire do

Answer 35

Carries the alternating potential from the supply

Question 36

Why does the earth wire do

Answer 36

Safety stops exterior of an appliance becoming live

Question 37

What is the national grid

Answer 37

A system of cables and transformers linking power stations to homes and businesses

Question 38

What does the power station do

Answer 38

Transfers the energy supply into electrical energy

Question 39

What do step up transformers do

Answer 39

Increase the potential difference from the power station to the transmission cables makes transmission more efficient as reduced current and therefore the heating effect

Question 40

Step down transformer do

Answer 40

Reduce the voltage from the transmission cables to a mich lower value for domestic use

Question 41

What is the purpose of a variable resistor

Answer 41

To adjust the resistance of the circuit and change the voltage across the components