P4 Ocr Gateway Revision

Front 1

Electrostatic Charge

Back 1

The charge created through rubbing certain types of insulating material together

Front 2

Attracting and Repelling

Back 2

Opposite charges attract, same charges repel

Front 3

Polythene Rod and Woolen Cloth

(Transfer of Electrons)

Back 3

Electrons move from the cloth to the rod. The rod becomes negatively charged, the cloth becomes positively charged.

Front 4

Acetate Rod and Woolen Cloth

(Transfer of Electrons)

Back 4

Electrons move from the rod to the cloth. Rod becomes positively charged, cloth becomes negative charged.

Front 5

Conductors and Charge

Back 5

Allow charged delocolised electrons to move freely around the positive metal ions

Front 6

Insulators and Charge

Back 6

Don't allow charged electrons to move freely and charge can build up.

Front 7

Electrostatic Shock

Back 7

By coming in contact with a charged material, the charge can quickly be passed onto you, causing an electrostatic shock.

By becoming charged from synthetic clothing or carpet, the charge can then be passed on from you to a conductor, giving you an electrostatic shock in the process.

Front 8

Dangers of Static Electricity

Back 8

-Can cause a spark

-Could lead to an explosion from a spark

-Fossil Fuels in very large tanks can become charged and possibly explode

-Causes lightning when a very large amount of built up energy transfers to the earth very quickly

Front 9

Con's of Static Electricity

Back 9

Attracts dust to TV, Computer and Phone screens when they become charged

Causes synthetic clothing to stick to you

Front 10

Prevention of Dangers

Back 10

Letting the charge pass through a conductor to Earth to stop initial charge build up

Insulating mats, shoes with insulated soles prevent rapid charge flow to the earth

Vehicles containing flammable gases are connected to the earth before unloading

Anti-static liquids to prevent charge build up

Front 11

Spray Painting

Back 11

-Paint particles gain electrons as they pass through the nozzle, making them negatively charged to be attracted by the positively charged car.

-The paint particles repel each other, making finer paint spray.

-The car gets an even coat of paint.

Front 12

Electrostatic Dust Precipitators

Back 12

-Soot in a chimney passes through a charged grid, becoming charged themselves.

-Charged metal plates attract the oppositely charged dust particles.

-When there is too much dist on the plates, they fall into the fireplace, showing the need for replacement

Front 13

Defibrillators

Back 13

-Two electrostatically charged paddles are placed on the patients chest with a direct circuit to the heart between the two of them.

-A high voltage shock is discharged from the paddles to the patient, causing the heart to contract and start beating again.

Front 14

Resistors

To be completed

Back 14

To be completed

Front 15

Earth Wire

Back 15

Green and yellow

If there is a fault and the case becomes live, the current passes through this wire to discharge it.

Front 16

Neutral Wire

Back 16

Blue

Completes the circuit

0 Voltage

Front 17

Live Wire

Back 17

Brown

Provides device with energy

230 Voltage

Front 18

Fuse

Back 18

Has a rating-if the current gets hotter than the rating, the live wire inside the fuse heats up, melts and breaks the circuit.

Front 19

Power Equation `

Back 19

Power = Voltage x Current

Front 20

Circuit Breaker

Back 20

Connected to the live wire and detects tiny changes in the current where there is a fault and breaks the circuit`

Front 21

Oscillations

Back 21

Back and forth, repetitive vibrations in waves

Front 22

Longitudal Waves

Back 22

A series of oscillations parallel to the direction of wave movement

Front 23

Compression of Longitudal Waves

Back 23

When the speaker cones move further out the air is bunched up, causing compression in a region of higher pressure

Front 24

Rarefaction

Back 24

Speaker cone moves back in to create a region of lower pressure

Front 25

Frequency

Back 25

The number of compressions passed per second

Front 26

Transverse Waves Particles

Back 26

Vibrate at right angles to the direction of wave movement.

Front 27

Longitudal Waves Particles

Back 27

Vibrate from side to side, closer together at a compression and further apart at rarefaction

Front 28

An increase in frequency....

Back 28

increases particle movement, causing them to vibrate more rapidly

Front 29

An increase in sound...

Back 29

causes particles to vibrate with a greater amplitude

Front 30

Ultrasound Waves

Back 30

Sound waves above the human hearing range=20 000Hz

High frequency and short wavelengths

Front 31

Ultrasound Scans

Back 31

-Ultrasound waves are beamed inside the body

-Waves reflect from different layers of the body

-Waves return at different times, depending on the layer of the body

-A computer processes the information and builds up an image of the inside of the body.

Front 32

Ultrasound Scans Pro's

Back 32

Don't damage living cells

Produce very clear images of soft tissue

Can be used for scanning the heart, liver and unborn babies

Front 33

X-Rays Con's

Back 33

Penetrating

Harmful to living cells at high levels

Hard to see any soft tissue

Front 34

Uses of Ultrasound Waves

Back 34

Monitoring blood flow

Scanning unborn babies

Breaking up Kidney Stones-Ultrasound is directed at the stones causing them to vibrate at a high frequency and break into small pieces passable through the patients urine

Front 35

Radioactive Decay

Back 35

Occurs when unstable nuclei break down they release one of three types of ionising radiation

Front 36

Alpha

Back 36

Very Ionising

Positive Charge

Attract electrons away from an atom

Greatest mass and charge

Front 37

Beta

Back 37

Negative Charge

Repel atoms away from an atom

Front 38

Gamma

Back 38

High frequency electromagnetic wave

Not very ionising

Very penetrating

Travels far

Front 39

The activity of a radioactive substance is the number of.....

Back 39

Radioactive decays per second

Front 40

Ionising Radiation in a Spark Chamber

Back 40

When ionising radiation passes through a gas in a spark chamber, it ionises it by taking some of the electrons from the neutral atoms, making them positive.

An electrical current (A spark) passes through the chamber

Front 41

Radioactivity and Time

Back 41

Activity in a radioactive substance gradually decreases over time

Front 42

Half-Life

Back 42

The amount of time a radioactive substance takes for activity in it to half

Front 43

Atomic Number

Back 43

Number of Protons and Electrons in an atom

Front 44

Mass Number

Back 44

The total number of Protons and Neutrons in an atom

Front 45

Radioactive Decay's Effects on a Nucleus

Back 45

Changes the atomic number and therefore the mass number

Front 46

An Alpha Particle is a Helium Nucleus, meaning that after a nucleus breaks down from an Alpha Particle......

Back 46

It's Mass Number drops by four and it's Atomic Number drops by two

A new element is formed with the atomic number change

Front 47

Beta Decay

Back 47

A neutron breaks into a proton and a beta particle

Atomic number goes up by one, mass number stays the same

A new element is formed with the atomic number change

Front 48

Gamma Decay

Back 48

Nucleus emits a high frequency electromagnetic wave with no mass or charge

Atom stays the same

Front 49

Background Radiation

Back 49

Radiation around us on a day to day basis

Front 50

Background Radiation Sources

Back 50

Hospitals

Nuclear weapon testing

Nuclear power

Radioactive decay in rocks

Less than 15% is man-made

Front 51

Alpha Radiation in Smoke Alarms

Back 51

When smoke enters the alarm it stops the alpha particles from ionising the air, causing the alarm to sound

Front 52

Radioactive Tracers Uses

Back 52

Map out the path of underground pipes

Track how material is dispersed upon entering a water supply

Finding blockages and cracks in pipes

Medical Uses

Front 53

Radiation in Finding Leaks

Back 53

Radiation can be added to an underground pipe, if there is a blockage or leak, the radiation past it will fail, letting the tracker above ground know where the leak is

Front 54

Radioactive Dating

Back 54

The amount of radioactive atoms in ancient materials can determine the age of that substance

Front 55

Carbon Dating

Back 55

Process of determining the age of a substance by how much Carbon 14 it contains, or decays over a certain period of time

Front 56

X-Rays and Gamma Rays

Back 56

-Ionising

-Type of electromagnetic wave

-Travel very fast and through vacuums like space

-High frequencies and short wavelengths

Front 57

X-Rays

Back 57

Produced by fast moving electrons fired at metal targets in the machine

Very high voltages are needed to accelerate electrons to a high enough speed to produce x-rays when they smash into the plate

Used by radiographer

Front 58

Controlling X-Rays and Gamma Rays

Back 58

X-Rays are easier to control as only the machine needs to be switched off to stop them.

A nucleus cannot be stopped from emitting gamma rays

A higher voltage in an x-ray machine will create shorter, more penetrating rays.

Front 59

Radioisotopes

Back 59

A radioactive version of a normally stable element

Front 60

Sterilisation

Back 60

Using Gamma Rays to sterilise medical equipment

Front 61

Gamma Knife

Back 61

A machine used to direct a wide beam of low intensity gamma rays into the body to kill cancerous cells.

Front 62

Con's of Using Gamma Ray's in Medical Treatments

Back 62

Can cause harm to cells and tissue surrounding the tumor so the amount added has to be limited.

Front 63

Radioactive Medical Tracers

Back 63

-A sample of radioactive atoms with a very short half life are injected into the body.

-When the source has spread throughout the body, camera's monitor the radiation leaving the body.

-A blockage or tear within organs can be detected with a change in the radiation emitted.

Front 64

Nuclear Fission

Back 64

-A nucleus absorbs an extra neutron, making it unbalanced and causing it to spin and distort and two or three neutrons are released, fissioning with other atoms

-It splits into two smaller nuclei

-Energy is released to power the generator

Front 65

Radioactive Waste in Nuclear Reactors

Back 65

Uranium is usually used as fuel. Nuclei in Uranium split into two smaller nuclei, which are very radioactive and often make up the waste from nuclear reactors.

Dismantling a Nuclear Reactor is hard because of the excessive radioactive waste.

Front 66

Submarine and Aircrafts Powered by Nuclear Reactors

Back 66

Generate electricity, power the engines, provide fresh water and oxygen

Front 67

Chain Reaction

Back 67

Neutrons released from one fission cause other atoms to go through nuclear fission

Front 68

Nuclear Reactors and Chain Reactions

Back 68

Carefully controlled process, steady-one fission will lead to only one more and one more etc

Front 69

Nuclear Weapons and Chain Reactions

Back 69

Explosive as the amount of fissions are not controlled, releasing masses of energy

One fission will lead to three more, then nine etc

Front 70

Control Rods

Back 70

Used in reactors to absorb neutrons, controlling the amount that split other atoms

Front 71

Nuclear Fusion

Back 71

Joining two hydrogen Nuclei to form one Helium Nuclei

As atomic nuclei are positively charged they need to be travelling extremely fast to fuse. Hard to recreate on earth

Front 72

Nuclear Fusion in Stars and Bombs

Back 72

Isotopes of hydrogen are fused together to produce helium, in the process releasing lots of energy. In bombs and stars conditions are hot enough to give enough energy to the nuclei so they can fuse.

Front 73

Pro's of Nuclear Fusion

Back 73

No carbon dioxide production

No radioactive waste is created

Front 74

Hydrogen Bomb

Back 74

An uncontrollable chain nuclear fission explosion is used to create the high temperatures needed for nuclear fusion between hydrogen atoms.

Core of Uranium and Plutonium.

Front 75

Cold Fusion

Back 75

In 1989, scientists claimed to have reached fusion at room temperature.

Data could not be used to recreate the experiment, so many scientists now believe that the results were false originally.