Physics Module 4

Question 0

How is static caused?

Answer 0

2 insulating materials rub together, electrons are scraped off leaving one positive (lack of electrons) and one negative (gained electrons)

Question 1

What is static electricity?

Answer 1

Build up of static caused by friction

Question 2

What happens if enough charge builds up?

Answer 2

Sparks/shocks

Question 3

How can you discharge a charged conductor?

Answer 3

Connect it to an earth wire with a metal strap. Electrons flow down the strap if negative, up if the charge is positive. This is earthing.

Question 4

What are ions?

Answer 4

Charged atoms/molecules

Question 5

Explain paper rollers

Answer 5

As paper drags over rollers, static builds up, spark, which can cause explosions

Question 6

What does earthing do?

Answer 6

Provide easy route for charges to travel to the ground so no charge builds up which can cause shocks

Question 7

What do anti-static sprays/cloths do?

Answer 7

Make the surface of a charged object conductive so they can carry the charge away

Question 8

What is a current?

Answer 8

A flow of electrical charge around a circuit

Question 9

What is voltage?

Answer 9

Driving force that pushes current round

Question 10

What does resistance do?

Answer 10

Slow down the flow

Question 11

What happens if you increase the voltage?

Answer 11

More current flows

Question 12

What happens if you increase the resistance?

Answer 12

Less current flows

Question 13

What is the purpose of the wire and the circuit breakers?

Answer 13

They break a circuit if there’s a fault

Question 14

Give a use of static electricity

Answer 14

Paint sprayers-charged gun, charged paint, drops repel, object attracts, fine spray,even,no waste.
Defibrillators, dust precipitators-smoke particles reach grid with high voltage and negative charge, particles attracted to metal plates, when heavy enough, fall to bottom.

Question 15

What is a variable resistor?

Answer 15

A resistor where the resistance can be changed.

Question 16

What happens when you turn the resistance up?

Answer 16

The current drops

Question 17

What happens when you turn the resistance down?

Answer 17

Current increases

Question 18

What does a longer wire do to the resistance?

Answer 18

More resistance, less current

Question 19

What happens to the resistance if the wire is thinner?

Answer 19

More resistance, less current

Question 20

What is the equation for resistance?

Answer 20

Resistance= voltage/current

Question 21

What is potential difference?

Answer 21

Same as voltage

Question 22

What does ammeter measure?

Answer 22

Current

Question 23

What does the brown wire do in a plug?

Answer 23

It’s a live wire that carries voltage

Question 24

What does the blue wire in a plug do?

Answer 24

It's a neutral wire, electricity flows out through it

Question 25

What does the earth wire do?

Answer 25

For safety

Question 26

What is double insulation?

Answer 26

A plastic casing over the plug

Question 27

What fuse rate do you need?

Answer 27

Slightly higher than the current, too high and won't blow the current if a fault develops

Question 28

What wave is ultrasound?

Answer 28

Longitudinal

Question 29

Give a use of ultrasound

Answer 29

Breaking down kidney stones- high energy waves turn it into particles/ body scanning, waves pass through body, some reflected, detected at different depths

Question 30

What's better, X-ray or ultrasound?

Answer 30

Ultrasound safer, can see soft tissue

Question 31

What is radioactivity made of?

Answer 31

Atoms with unstable nuclei

Question 32

What does decay give out?

Answer 32

Alpha, beta, gamma

Question 33

Explain alpha

Answer 33

Helium nucleus, mass 4, charge +2, 2 protons, 2 neutrons

Question 34

Explain beta particles

Answer 34

Fast moving electron, no mass, charge of -1

Question 35

What happens to an equation when a nucleus emits alpha?

Answer 35

Top number -4, bottom number -2

Question 36

What happens to an equation when a nucleus emits beta?

Answer 36

Top number 0, bottom number +1

Question 37

When does ionisation occur?

Answer 37

When particles gain/lose electrons

Question 38

Why do alpha particles make good ionizers?

Answer 38

Large and easy to collide with, highly charged to remove electrons from atoms

Question 39

What does radiation cause?

Answer 39

Cause cells to multiply cancer

Question 40

What is the most dangerous radiation outside the body?

Answer 40

Beta and gamma

Question 41

What kind of Waves are X-rays and gamma rays?

Answer 41

Electromagnetic waves

Question 42

How are gamma rays released?

Answer 42

Released from unstable atomic nuclei when they decay

Question 43

How are X-rays produced?

Answer 43

Firing high speed electrons at a heavy metal

Question 44

What are some uses of radiation and background radiation?

Answer 44

Tracers in industry to find leaks- gamma, short half life, detectable

Question 45

How do smoke detectors work?

Answer 45

Weak alpha source placed in, causes ionisation of air particles, which cues a flow of current, if a fires smoke particles hit by alpha particles, less ionisation of air particles, reduced current, alarm

Question 46

Where does background radiation come from?

Answer 46

Unstable isotopes (air, rocks) space (cosmic rays) human activity, waste

Question 47

Why does radioactivity decrease over time?

Answer 47

More unstable nuclei decay

Question 48

What is half life?

Answer 48

Time taken for half of the radioactive nuclei to decay

Question 49

What does a short half life mean?

Answer 49

Radioactivity falls quickly, lots of nuclei decay in a short time

Question 50

Give a medical use of radiation

Answer 50

Radiotherapy-treatment of cancer using gamma rays, focused on tumour with wide beam rotated around patient so less exposure to normal cells. Tracers in medicine-beta/gamma, short half life Sterilisation of tools- gamma, better than heat, won't melt plastic

Question 51

What is a use of radioactive dating?

Answer 51

Can date rocks, measure amount of radioactive isotope, and knowing half life, you can find the age

Question 52

Where is carbon 14 found?

Answer 52

In living things, when they die they stop exchanging gases with the air outside, carbon 14 is trapped inside, and decays with a half life is 5730 years

Question 53

Explain uranium isotopes

Answer 53

They have long half lives, when they decay they produce stable isotopes of lead

Question 54

What is nuclear fission?

Answer 54

Splitting of uranium atoms

Question 55

How does nuclear fission work?

Answer 55

A nuclear reactor, causes a chain reaction or uranium and plutonium atoms split and release heat energy

Question 56

How does uranium 235 work?

Answer 56

Used in some reactors, it's stable but needs to be unstable to split, so slow moving electrons are fired at the atom. A neutron joins to create u236 which is unstable and splits to form 2 smaller nuclei, which release energy and fast moving neutrons, which cause a chain reaction

Question 57

What are nuclear bombs?

Answer 57

Out of control chain reactions

Question 58

How do control rods control chain reactions?

Answer 58

Free neutrons start a fission reaction, neutrons collide with uranium, split which raises the temperature. They limit the rate of fission by absorbing excess neutrons and keep the reaction in control.

Question 59

What is nuclear fusion?

Answer 59

Joining of small atomic nuclei, 2 small nuclei combine to make a large nucleus

Question 60

What are the conditions needed for fusion?

Answer 60

High temperatures and pressures

Question 61

Why are fusion reactors hard to build?

Answer 61

Materials can't take the heat needed

Question 62

Give am example of am experimental reactor

Answer 62

JET- Joint European Torus

Question 63

What bombs do fusion reactions happen in?

Answer 63

Hydrogen/H bombs

Question 64

What is cold fusion?

Answer 64

Nuclear fusion at room temperature