P2

Question 1

What are amps?

Answer 1

The unit of current

Question 2

What are Coulombs?

Answer 2

The unit of charge

Question 3

What is a diode?

Answer 3

A component that only allows current to flow in one direction. They have huge resistance in the reverse direction

Question 4

What is the earth wire and what does it do?

Answer 4

The green and yellow striped safety wire
It prevents an appliance from becoming live

Question 5

What are electric field lines?

Answer 5

Lines representing an electric field that point in the direction in which a positive charge would experience an electric force

Question 6

What is an electrical field?

Answer 6

A region in which charge will experience a non contact, electric force. All charged forces have an electric field around them- it’s stronger the closer to the charge you are

Question 7

What is an electrical current?

Answer 7

The rate of flow of electrical charge- is value is the same at any position in a single closed loop

Question 8

What is electrical work?

Answer 8

When charge flows in a circuit, electrical work is said to be done

Question 9

What is a filament lamp?

Answer 9

Light emitting component that consists of metal filament- the resistance increases as the temperature of the filament increases

Question 10

What does insulation mean?

Answer 10

The coating around power cables that prevent electrocution- they’re colour coded for easy identification

Question 11

What is a LDR?

Answer 11

Light Dependent Resistor- a light sensitive component whose resistance increases as the temperature decreases

Question 12

What is the live wire?

Answer 12

It’s the brown coloured wire that carries the alternating current from the supply in a mains power supply

Question 13

What is the mains electricity frequency and voltage in the UK?

Answer 13

230V
50Hz
(It’s A.C.- alternating current)

Question 14

What is the neutral wire?

Answer 14

The blue coloured wire
It completes the circuit in a mains power supply

Question 15

What is a non contact force?

Answer 15

A force experienced between two separate forces (e.g. gravity)

Question 16

What are ohms?

Answer 16

The unit of resistance

Question 17

What happens to the current and potential difference in a parallel circuit?

Answer 17

Components are connected in parallel- they have the same potential difference across each component. The total current is equal to the sum of currents flowing through each component.

Question 18

What is potential difference?

Answer 18

The product of a component’s resistance and the magnitude of the current flow through it

Question 19

What is the difference between resistance in a parallel circuit compared to resistance in a series circuit?

Answer 19

PARALLEL- total is always less than that the resistor with the least individual value
SERIES- Total resistance is always the sum of all resistances in each individual component

Question 20

What is the current and voltage like in a series circuit?

Answer 20

The components have the same current flowing through them, but they equally share the total potential difference from the supply

Question 21

What are step down transformers?

Answer 21

Devices between the transmission cable and the consumer that LOWER potential difference levels so it’s at a safe and usable level

Question 22

What are step up transformers?

Answer 22

Devices that increase the potential difference generated at power stations so the power transmitted along the transmission cable is higher

Question 23

What is the National Grid?

Answer 23

The network of power stations, transformers and cables that connect consumers to power stations

Question 24

What does a thermistor do?

Answer 24

It’s a temperature dependent component, whose resistance increases as its temperature decreases

Question 25

What is resistance?

Answer 25

How hard it is for the current to flow

Question 26

What is current?

Answer 26

The rate of flow of charge

Question 27

What is direct current?

Answer 27

Current that only flows in one direction

Question 28

What is alternating current?

Answer 28

Where the direction of the current flow continually changes

Question 29

Where are step up transformers used?

Answer 29

They’re used between power stations and power lines

Question 30

Where are step down transformers used?

Answer 30

They’re used between power lines and houses

Question 31

What are power lines?

Answer 31

Lines that transports current at very high voltages (to reduce energy loss) from power stations to houses

Question 32

What happens to the resistance of a thermistor as temperature increases?

Answer 32

The resistance of a thermistor decreases as the temperature increases.

Question 33

What is a potential use for a thermistor?

Answer 33

A thermistor could be used to make a thermostat keep a building at a certain temperature.

Question 34

What happens to the resistance of an LDR as light intensity increases?

Answer 34

The resistance of an LDR decreases as light intensity increases.

Question 35

What is a potential use for an LDR?

Answer 35

An LDR could be used to switch on lights when it gets dark.

Question 36

What is the National Grid made up of?

Answer 36

The National Grid is made up of cables and transformers linking power stations to consumers.

Question 37

What is the purpose of step up transformers in the National Grid?

Answer 37

Step up transformers are used to increase the potential difference for the transmission cables.

Question 38

What is the purpose of step down transformers in the National Grid?

Answer 38

Step down transformers are used to decrease the potential difference for consumers.

Question 39

What type of current does mains electricity supply?

Answer 39

Mains electricity supplies an alternating current.

Question 40

What is the frequency of the mains supply in the UK?

Answer 40

In the UK, the mains supply has a frequency of 50Hz.

Question 41

What is the voltage of the mains supply in the UK?

Answer 41

The mains supply in the UK is about 230 V.