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

Perspex Rod

Answer 2

Loses electrons if it is rubbed by a woollen cloth (becomes positively charged)

Question 3

Unlike charges

Answer 3

Attract each other

Question 4

Like charges

Answer 4

Repel each other

Question 5

Earthing

Answer 5

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

Question 6

Static Electricity

Answer 6

Is a build up of electric charge that can occur on good insulators e.g. Polythene and Perspex Rods

Question 7

An Electric Current

Answer 7

Is a flow of electric charge (electrons)

Question 8

Conductors

Answer 8

Are substances which allow electric current to flow through them freely

Question 9

Insulators

Answer 9

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

Question 10

A Closed Circuit

Answer 10

Is needed for the current to flow, if there is a break in a circuit then the current won’t flow. -> the electric energy can’t get through.

Question 11

Energy provided…

Answer 11

…by a battery or power pack, it is needed to move the current around the circuit

Question 12

The battery pumps electrons

Answer 12

From its negative end around a circuit

Question 13

The electrons are attracted

Answer 13

Back to the positive end of the battery

Question 14

Potential Difference

Answer 14

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

Question 15

Whenever there is a potential difference

Answer 15

Electricity will flow

Question 16

This potential difference is known as..

Answer 16

Voltage and is measured in volts

Question 17

Resistance

Answer 17

Is the opposite to the flow of electrons. The unit is Ohm, and it is measured using an Ohmmeter

Question 18

If a resistor

Answer 18

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

Question 19

Ohm’s Law

Answer 19

Ohm’s law states that voltage is directly proportional to current.

Question 20

DC

Answer 20

Direct current goes in one way only e.g the current from a battery.

Question 21

AC

Answer 21

Alternating current changes very quickly, many times a second.

Question 22

Mains Supply

Answer 22

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 23

The ring circuit

Answer 23

All households have a ring circuit made of love, neutral and earth wires.
Sockets are tapped off at points along this ring circuit.

Question 24

Fuse

Answer 24

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

Question 25

Circuit breakers

Answer 25

Are used in the fuse board of the home, and this trips, to stop the flow of current from entering the house.

Question 26

Live wire

Answer 26

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

Question 27

Neutral wire

Answer 27

Is blue and is connected to the left hand side.

Question 28

Earth wire

Answer 28

Is a safety wire, no electricity flows in the earth wire unless the appliance it is attached to becomes "live" eg a toaster, in this case the earth wire would carry the current to the earth instead of you electrocuting yourself should you touch the toaster.

Question 29

Watt

Answer 29

The Watt (W) is the unit of electrical power

Question 30

ESB charges a fee for the number of

Answer 30

Kilowatts (1000 watts) used per hour

Question 31

ESB's unit of electricity is

Answer 31

The kilowatt hour (KWh)

Question 32

Kilowatt hour

Answer 32

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

Question 33

Heating effect

Answer 33

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

Question 34

Chemical effect

Answer 34

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

Question 35

Magnetic effect

Answer 35

Electromagnet made with a wire wrapped around a nail, electric motor, speakers, circuit breaker I'm fuse board.

Question 36

Electronics

Answer 36

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

Question 37

Diode

Answer 37

A diode is a component that will allow current to flow in one direction only

Question 38

Forward Biased

Answer 38

If the positive end of the battery is connected to the positive end of a diode the diode is said to be "forward biased" and current can flow.

Question 39

Reverse Biased

Answer 39

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 40

A diode can be used

Answer 40

Change alternating current into direct current

Question 41

Electronic devices such as radios, tape recorders and calculators

Answer 41

Need low voltage direct current. They work off the main ESB supply which is a high voltage alternating current because they have an adaptor built into them. The adaptor has a transformer which reduces the voltage and a diode which changes the current from a.c to d.c

Question 42

Light emitting diode

Answer 42

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

Question 43

Current will only flow when LED

Answer 43

Is forward biased

Question 44

LED's use only tiny currents so

Answer 44

A resistor must be connected in series with it

Question 45

LED's are useful as they are

Answer 45

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

Question 46

Light Dependent Resistor

Answer 46

It is a resistor whose resistance depends on light

Question 47

When light falls on an LDR

Answer 47

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