Current Electricity

Question 0

The equation to find charge

Answer 0

Charge= current x time

Question 1

Definition of current

Answer 1

The rate of flow of charge

Question 2

Definition of voltage

Answer 2

The driving force that pushes the current round

Question 3

Definition of resistance

Answer 3

Anything in the circuit which slows the flow down

Question 4

Equation to find the resistance

Answer 4

Resistance = voltage

Current

Question 5

What at the rules for current in a series circuit

Answer 5

They are connected in a line
The current can only flow through all or none
If one component is removed it stops

Question 6

What are the rules for parallel circuits

Answer 6

Each component is separately connected
Removing one will not affect it
Used for light switches
It’s all connected in loops

Question 7

What is the graph for a resistor/ wire

Answer 7

The current is proportional to the voltage. Different resistors have different resistances

Question 8

What is the graph for the filament lamp

Answer 8

As the temp increases the resistance increase and curves

Question 9

What is the graph for the diode

Answer 9

Current will only flow through a diode in one direction

Question 10

What is a thermistor

Answer 10

A temperature dependant resistor
Hot conditions, resistance drops
Cool conditions, resistance increases
Used as temperature detector

Question 11

What is a light dependant resistor

Answer 11

A resistor that changes resistance dependant of the amount of light on it
Bright light resistance falls
Darkness resistance increases
Used as a burglar detector

Question 12

What is the unit for resistance

Answer 12

Ohm

Question 13

What is current measured in

Answer 13

Amps

Question 14

What is the difference between the ends of the cell

Answer 14

Potential difference

Question 15

What is current measured with

Answer 15

Ammeter

Only connected in series

Question 16

What is potential difference measured with

Answer 16

A voltmeter

Only connected in parallel

Question 17

Why are metals good conductors

Answer 17

They have delocalised electrons

Question 18

Why are non metals insulators

Answer 18

They have no delocalised charge carriers

Question 19

How are plugs wired correctly

Answer 19

The right coloured wire is connected to each pin and firmly screwed in
No bare wires
The cable grip is lightly fastened over the cable outer layer

Question 20

What must plugs be made of

Answer 20

Metal parts must be made of copper or brass

Cable grip and insulation must be made of rubber or plastic

Question 21

Live wire

Answer 21

brown, alternates between positive and negative voltage of about 230V
electricity normally flows through the live wire and out the neutral wire

Question 22

Neutral wire

Answer 22

Blue, is always at 0V

Question 23

Earth wire

Answer 23

green and yellow, it can never become live beacsue the appliance has no metal parts meaning it is double insulated

Question 24

Plastic as an insulator

Answer 24

stops a current flowing which means you can’t get a shock

Question 25

Fuses

Answer 25

A surge in current melts the fuse which cuts off the live supply preventing an electrical shock and the risk of fire

Question 26

Circuit breakers

Answer 26

an electrical safety device that is used to protect the circuit from damage if too much current flows
When they detect a surge in current in a circuit they break the circuit by opening a switch
It can easily be reset by flicking a switch on the device

Question 27

equation for power in electrical circuits

Answer 27

P= current x voltage

Question 28

equation for energy in electrical circuits

Answer 28

E = current x voltage x time

Question 29

Alternating current

Answer 29

the current is constantly changing direction

eg. UK mains electricty

Question 30

Direct current

Answer 30

The current keeps flowing in the same direction

eg. cells and batteries