Electricity

Question 0

Where is the neutral wire?

Answer 0

Bottom left

Question 1

Where is the live wire?

Answer 1

Bottom right

Question 2

What holds the cable in the plug?

Answer 2

Cable grip

Question 3

Why are the metal parts made of copper or brass?

Answer 3

Good conductors

Question 4

Appliances must be …………………..

Answer 4

Earthed or insulated

Question 5

The live wire alternates between …………

Answer 5

High +ve and -ve voltage

Question 6

What safety precautions should be taken using plugs to avoid hazards and electric shock?

Answer 6

Check for damage to plugs or insulating casing on mains operated devices.
Check cable isn’t frayed, damaged insulation can expose ‘live wires’
Check cables aren’t too long, or more likely to get damaged or trip people up.
No water around electric sockets or mains operated devices.
Never push metal in a socket - solved by using socket covers.

Question 7

What does earthing or fuses do?

Answer 7

Prevent fires and electric shocks by blowing the fuse and cutting off the live supply.

Question 8

What advantages do circuit breakers have?

Answer 8

They break the circuit by opening a switch
Can be easily reset no need to replace
Faster than a fuse

Question 9

What is the equation for electrical power?

Answer 9

Power= Current x voltage

P = I x V

Question 10

What is electrical power?

Answer 10

Rate at which an appliance transfers energy

Question 11

What is the equation of energy transferred?

Answer 11

Energy transferred = Current x voltage x time

E = I x V x t

Question 12

What are resistors?

Answer 12

An electrical current heats the resistor increasing the resistance so less current will flow
Fuses use this to protect circuits

Question 13

What is current?

Answer 13

The rate of flow of charge round a circuit

Question 14

What is voltage?

Answer 14

The driving force that pushes current and the energy transferred per unit charge passed.

Question 15

How do you increase current?

Answer 15

Increase voltage

Decrease resistance

Question 16

What is resistance?

Answer 16

Slows the flow down

Question 17

What is an ammeter?

Answer 17

Measures the current in amps.
Placed in a series circuit
Tells you how many coulombs of charge are passing through the lamps per second.

Question 18

What is a voltmeter?

Answer 18

Measure the voltage in volts
Place in a parallel circuit
Voltage, v1, across the lamp tells you how many joules of energy are being converted to heat and light per coulomb of charge passing through the lamp.
V1 + V2 = V.

Question 19

What is the difference between a.c and d.c supply?

Answer 19

Mains supply - a.c, constantly changing (alternating current)
Battery supply - d.c, (direct current)

Question 20

What is the equation for voltage?

Answer 20

Voltage = Current x resistance

V = I x R

Question 21

What does the I-v graph for a
Metal filament lamp
Wire
Diode

Answer 21

Lamp - curve graph
Wire - straight diagonal
Diode - in the x axis then straight up

Question 22

What are light emitting diodes used for?

Answer 22

Digital clocks
Remote controls
Traffic lights

Question 23

Describe a series circuit?

Answer 23

Everything on one line
Current same everywhere
Voltage is split

Question 24

Describe parallel circuits?

Answer 24

Branches Same voltage Split current

Question 25

What is the equation for charge?

Answer 25

Charge = Current x time Q = I x t

Question 26

Voltage is the ............. Per .................

Answer 26

Energy transferred | Unit charge passed

Question 27

One volt is one joule per .............

Answer 27

Coulomb

Question 28

What is static electricity caused by?

Answer 28

Friction

Question 29

``` What are the units for the following: Ampere Coulomb Joule Ohm Second Volt Watt ```

Answer 29

``` Ampere, A Coulomb, C Joule, J Ohm, ♎️ Second, s Volt, V Watt, W ```

Question 30

Understand the uses of insulation, double insulation, earthing, fuses, and circuit breakers.

Answer 30

Insulation - all mains wiring is double insulated, preventing separate conducts (live, neutral and earth) touching a 'live' (mains voltage) wire. Double insulation - no chance of electric shock from casing. Earthed - earth wire ensures outer casing is held at OV and provides low resistance path for current in the event of a fault. Fuses - fitted in plugs and in consumer unit next to electricity meter. They are ceramic heat proof tubes that melt when the current size is exceeding and so cut off live supply, but need replacing. Circuit breakers - do same job as fuses, breaking live connection. Operated magnetically and may be reset by pressing a button.

Question 31

What does a current in a resistor result in?

Answer 31

The electrical transfer of energy and an increase in temperature.

Question 32

What can lamps and LED's be used for?

Answer 32

To indicate the presence of a current in a circuit.

Question 33

What is the equivalent of 1 volt?

Answer 33

1 volt = 1 joule per coulomb

Question 34

What is electric current in solid metallic conductors? (E.g. Copper, silver, gold - electricity conductors)

Answer 34

A flow of negatively charged electrons.

Question 35

What materials do not conduct electricity?

Answer 35

``` Rubber Glass Plastic Dry wood (Usually non metallic) ```

Question 36

Unlike charges...... Like charges......

Answer 36

Unlike charges attract Like charges repel

Question 37

How are positive and negative electrostatic charges produced on materials?

Answer 37

By the loss and gain of electrons.

Question 38

Describe an experiment to investigate how insulating materials can be charged by friction.

Answer 38

Rub a clear plastic ruler with a dry cloth. Then hover the ruler over small pieces of dry paper, they will be attracted to the ruler. Or you can place the rubbed ruler next to running water, the water should bend towards the ruler.

Question 39

Explain electrostatic phenomena.

Answer 39

In solids the positions of atoms are fixed and therefore the nuclei and protons within them are fixed, but the surrounding electrons can be made to move from place to place under certain conditions.

Question 40

Explain the potential dangers of electrostatic charges / static electricity.

Answer 40

Fuelling tankers - fuel flows out of filler pipe, static builds up, leads to a spark and in dusty, fumy places - boom! Solution - make nozzles out of metal so charge is conducted away instead of building up. Beneficial to have earthing straps between fuel and fuel pipe. Lightning - rain drops and ice bump together in rain clouds, knocking off electrons, leaving top of cloud positively charged and bottom of cloud negatively charged. Creates huge voltage and bog spark.

Question 41

Explain some of the uses of electrostatic charges / static electricity.

Answer 41

Inkjet printers - charging ink droplets in inkjet printers allows droplets to be directed to places on paper by deflecting them between charged plates. They are attracted to plates with opposite charge to them. Photocopiers - image plate is positively charged and an image of what you're copying is projected onto it. Whiter parts of image make light fall on plate. Charged bits attract negatively charged black powder which is transferred onto positively charged paper. Paper is heated so powder sticks.