Static and current Electricity

Question 1

Polythene rod

Answer 1

Gains electrons if a woollen cloth is rubbed on it (becomes negatively charged)

Question 2

A Perspex rod

Answer 2

Looses electrons

Question 3

Earthing

Answer 3

Occurs when a charged object looses its charge to the earth through a conductor

Question 4

Static electricity

Answer 4

A build up of electric charge that can occur on good insulators e.g. Polythene and Perspex rods

Question 5

Current electricity

Answer 5

Is the flow of electric charge

Question 6

Conductors

Answer 6

Are substances which allow electric current to flow through them freely

Question 7

Insulators

Answer 7

Are substances which do not allow electric current to flow through them

Question 8

Closed circuits

Answer 8

A closed circuit is needed for the current to flow, if there is a break in a circuit then the current won’t flow

Question 9

Energy is provided

Answer 9

By a battery or power pack is needed to move the current around the circuit

Question 10

The battery pumps electrons

Answer 10

From its negative and around a circuit

Question 11

The electrons are attracted

Answer 11

Back to the positive end of the battery

Question 12

Potential difference

Answer 12

The difference in electrical pressure between the positive and negative ends of a battery/power pack

Question 13

Whenever there is potential difference

Answer 13

Electricity will flow

Question 14

This potential difference is known as

Answer 14

Voltage and is measured in volts

Question 15

Resistance

Answer 15

Is the opposition to the flow of electrons. The unit is the Ohm and it is measured using a Ohmmeter

Question 16

If a resistor

Answer 16

Is placed in an electric circuit it will slow down the flow of electrons

Question 17

DC

Answer 17

DC goes in one direction only e.g. The current from a battery

Question 18

AC

Answer 18

AC changes very quickly, many times a second

Question 19

Mains supply

Answer 19

The mains supply (the electricity in our homes, supplied by the ESB) is A.C.
It flows at a potential difference of 230 volts

Question 20

The ring circuit

Answer 20

Made of live, neutral, and earth wires

Sockets are tapped off at points along this ring circuit

Question 21

Fuses

Answer 21

Is a safety device that prevents the circuit from overheating
It will melt when it is too hot, breaking the circuit

Question 22

Circuit breakers

Answer 22

Kiss used in the fuse board of the home, and this trips, to stop the flow of current from entering the house
When a fuse blows it has to be replaced, modern houses have circuit breakers which act like a bimetallic strip and simply switch off if the current to ……….

Question 23

Live wire

Answer 23

Is brown and carries most electricity it is connected to the plugs fuse on the right hand side

Question 24

The neutral wire is blue and is connected to the left hand side

Answer 24

is blue and is connected to the left hand side

Question 25

The watt

Answer 25

Is the unit of electrical power

Question 26

The ESB charges a fee for the number of kilowatts (1000 watts) used per hour

Answer 26

kilowatts (1000 watts) used per hour

Question 27

ESB's unit of electricity

Answer 27

is the kilowatt hour (kWh)

Question 28

A kilowatt hour

Answer 28

Is the electrical energy used by a 1kW appliance running for 1 hour

Question 29

Heating effect

Answer 29

Boil water in a kettle, immersion heater, electric cooker, fuse in plug

Question 30

Chemical effect

Answer 30

Electroplating cheap metal with more expensive metal e.g. Silver, electrolysis (splitting) of water, mobile phone battery

Question 31

Magnetic effect

Answer 31

Electromagnet made with a wire wrapped around a nail, electric motor, speakers, circuit breaker in fuse board

Question 32

Electronics

Answer 32

Is the careful and exact control of tiny amounts of electric current

Question 33

A diode

Answer 33

Is a component that will allow current to flow in one direction only If the positive end of a battery is connected to the positive end of a diode the diode is said to be Forward Biased and current can flow If the positive end of the battery is connected to the negative end of the diode it is said to be Reverse Biased and no electricity can flow

Question 34

A diode can be used

Answer 34

To change alternating current into direct current

Question 35

Electronic devices such as radios, tape recorders and calculators

Answer 35

Need low voltage direct current

Question 36

Light Emitting Diodes(LED)

Answer 36

Is a diode that gives out light when a current flows through it

Question 37

Current will only flow when LED

Answer 37

Is forward biased

Question 38

LED's use only tiny currents

Answer 38

So a resistor must be connected in series with it

Question 39

LED's are useful as they are

Answer 39

Cheap, reliable and long lasting and use far less current than other light bulbs

Question 40

Light Dependent Resistor (LDR)

Answer 40

Is a resistor whose resistance depends on light

Question 41

When light falls on a LDR

Answer 41

It's resistance decreases, this low resistance will allow a current through the circuit