P2 Electricity

Question 1

What does a fixed resistor do

Answer 1

Limits the current in a circuit

Question 2

What does a variable resistor do

Answer 2

Allows the current in a circuit to be varied

Question 3

What does a thermistor do ?

Answer 3

Allows the current depending on the temperture

Question 4

What does a fuse do ?

Answer 4

A fuse is designed to melt and break the circuit if the current is too great

Question 5

What does a cell do

Answer 5

It pushes the elctrons around a complete circuit

Question 6

What does a switch do

Answer 6

A switch enables you to break and complete a circuit , so turn on and off

Question 7

What does a bulb do

Answer 7

A bulb emits light when current passes through it

Question 8

What does a diode do ?

Answer 8

A diode allowes current through in only one direction.

Question 9

What does a LED do ?

Answer 9

Emits light when the current passes through it

Question 10

What does a LDR do ?

Answer 10

Decreases in resistance as light intensity increases

Question 11

What does an ammeter do ?

Answer 11

Used to measure the elctric current ( amps )

Question 12

What does a voltmeter do ?

Answer 12

Used to measure the electric potential difference

Question 13

What is electric current

Answer 13

A flow of electrical charge

Question 14

Current is measured in

Answer 14

Amperes

Question 15

Charge is measured in

Answer 15

Coulombs

Question 16

What is the potential difference

Answer 16

It is the “driving force “ that pushes charge around the ciruit

Question 17

What ia resistance

Answer 17

Anything that slows down the charge

Question 18

Formula linking charge flow, current and time

Answer 18

Charge flow = current x time

Question 19

The greater the resistance acroos a component the

Answer 19

Smaller the current that flows

Question 20

What are ohmic conductors

Answer 20

Components with a fixed resistance ( resistance won’t change with current )

Question 21

Examples of ohmic conductors

Answer 21

Wires and resistors

Question 22

Some components however do have changing

Answer 22

Resistance

Question 23

Example of components with changing resistance

Answer 23

Filament lamp or a diode

Question 24

The resistance increases with

Answer 24

Temperature

Question 25

What is an IV characteristic

Answer 25

A graph showing how the current flowing through a component changes as the potential difference across it changes

Question 26

Where are thermistors used ?

Answer 26

Used in car engines and central heating thermostats

Question 27

Where is a LDDR use ?

Answer 27

Automatic night light or outdoor lighting.

Question 28

In a series circuit the components are all connected

Answer 28

In a line between the ends of the power supply.

Question 29

In a series circuit if you remove one component then

Answer 29

The circuit is broken, so all components stop working

Question 30

In a series circuit the total potential difference is shared

Answer 30

Between all of the components

Question 31

In a series circuit if you dd all the potential difference of each component you will get the

Answer 31

Potential difference of the power supply

Question 32

Inna series circuit the total resistance of two components is found by

Answer 32

Adding up their resistance