P2P10 - Electrical circuits

Question 1

What is current?

Answer 1

The flow (movement) of electric charges.
The flow of electrons.

Question 2

What is current measured in?

Answer 2

Amperes (A)

Question 3

How do you calculate electrical current?

Answer 3

Current = Charge X Time

Question 4

Whats an electrical insulator/conductor

Answer 4

A material that doesn’t/does allow current to pass through

Question 5

Whats an example of electrical insulator?

Answer 5

PLastic/glass

Question 6

Whats an example of electrical conductor?

Answer 6

Metals

Question 7

Why can electrical conductors conduct electricity?

Answer 7

Because there are delocalised electrons

Question 8

What is potential difference?

Answer 8

The difference in the amount of energy that charge carriers have between two points in a circuit.

Question 9

What is PD measured in?

Answer 9

Volts (V)

Question 10

How do we measure PD?

Answer 10

Using a Voltmeter

Question 11

What is the PD of one volt?

Answer 11

The PD is equal to one Joule of energy being used by one Coulomb of charge when it flows between two points in a circuit.

Question 12

What does an ammeter measure?

Answer 12

The flow of current that runs through it

Question 13

What is resistance?

Answer 13

How difficult it is for current to flow through a component.

Question 14

What is resistance measured in?

Answer 14

Ohms

Question 15

What is the size of current affected by?

Answer 15

The resistance
The potential difference

Question 16

Whats the equation for resistance?

Answer 16

Resistance =
Potential difference / Current

Question 17

What happens if the wire in a circuit is longer?

Answer 17

The resistance increases

Question 18

What is Ohms law?

Answer 18

Potential difference =
Currrent X resistance

Question 19

How will stretching a wire affect its resistance?

Answer 19

Resistance will increase

Question 20

What is a diode?

Answer 20

A component that only allows current to flow through it in one direction.

Question 21

What is a Rectifier?

Answer 21

A component that turns an alternating current into a direct current.

Question 22

What is a thermistor?

Answer 22

A thermistor is a component thats resistance changes with its temperature.

Question 23

What effect will increased light intensity have on an LDR?

Answer 23

Decreased resistance

Question 24

In a series circuit, what do resistors do?

Answer 24

Oppose the flow of electric current.
Increase resistance

Question 25

What happens to the current when the wires split in a parallel circuit?

Answer 25

Splits equally throughout the 2 wire branches

Question 26

What is voltage?

Answer 26

A measure of the difference in energy between one part of a circuit and another.

Question 27

What is not split between 2 branches in a parallel circuit?

Answer 27

Voltage

Question 28

In a parallel circuit what is the current through the energy source equal to?

Answer 28

The sum of the currents in the separate branches.

Question 29

What colour stripes does the earth wire have and whats its potential?

Answer 29

Green and yellow 0V

Question 30

What colour is the live wire and whats its potential?

Answer 30

Brown 230V

Question 31

What colour is the neutral wire?

Answer 31

Blue

Question 32

Whats the potential difference across the mains power supply in the UK?

Answer 32

230V

Question 33

What is the National Grid?

Answer 33

The network of cables and transformers that connect power stations with houses and shops in the United Kingdom.

Question 34

What are circuit breakers?

Answer 34

Special devices that switch off the flow of current if the current is higher than a certain value.

Question 35

What are fuses?

Answer 35

Fuses contain a thin wire that melts if the current flowing through an appliance is too high.

Question 36

What is an earth wire?

Answer 36

An earth wire is a low resistance wire that connects the metal case to the ground

Question 37

Why is the live wire dangerous?

Answer 37

- Carries alot of electrical energy - Might still hold potential difference when turned off - High chance of shocking you

Question 38

What is the unit for potential difference?

Answer 38

Volts

Question 39

What is measured using Coulombs?

Answer 39

Charge