Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics GCSE > Radioactivity > Flashcards

Radioactivity Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards GCSE Religious Studies - Edexcel Route A flashcards AP® Physics flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Geography - AQA flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route B flashcards
1
Q

Relative atomic mass of an electron

A

1/1836

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do radioactive substances give out nuclear radiation?

A

They contain unstable nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Two features of radioactive decay

A
  1. Random: no one can predict which unstable nucleus is going to decay and when
  2. Spontaneous: can’t be switched off or increased, completely unaffected by physical conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does radioactive decay compare to popping popcorn?

A

Popping popcorn is random but it can be controlled (turning the fire lower/higher etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Two ways to detect radiation

A
  1. Geiger-Müller tube

2. Photographic film

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does a Geiger-Müller tube work?

A

Radiation enters tube ⮕ ionises the gas
Ions attracted to electrodes ⮕ produce current ⮕ results in a voltage pulse
Each voltage pulse is counted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does photographic film work?

A

It goes darker when it absorbs radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Natural sources of background radiation

A
  1. Radon gas from the ground
  2. Food & drink (bananas, Brazil nuts)
  3. Cosmic rays (esp. at high altitudes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Artificial sources of background radiation

A
  1. Medical: cancer treatments

2. Nuclear power and weapons test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which is heavier: alpha or beta radiation?

A

Alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is alpha radiation?

A

2 protons and 2 neutrons (a Helium nucleus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do alpha particles do in an electric field?

A

Deflect toward the negative plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do alpha particles do in a magnetic field?

A

Deflects the opposite direction to beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the range of alpha particles in air?

A

3-5 cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can alpha particles be stopped by?

A

Paper, skin, few cm of air (not very penetrating)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How ionising are alpha particles?

A

Very: most ionising type of radiation!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do ionising substances do?

A

Make ions by removing electrons or breaking up molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do beta particles do in an electric field?

A

Deflect towards the positive plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do beta particles do in a magnetic field?

A

Deflect in the opposite direction to alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the range of beta particles in air?

A

15-100 cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can beta particles be stopped by?

A

3-5 mm aluminium (thin metal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do gamma rays do in an electric field?

A

Not deflected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do gamma rays do in a magnetic field?

A

Not deflected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Range of gamma radiation in air

A

Many km

25
Q

What can gamma radiation be stopped by?

A

3-5 cm lead

3-5 m concrete

26
Q

How does beta decay work?

A

Neutron turns into a proton and release the electron (which is the beta particle)

27
Q

Half life definition

A

The average time taken for half the radioactive nuclei in a sample to decay

28
Q

What is the unit for count rate?

A

Becquerels (Bq)

Counts per second

29
Q

Dangers of ionising radiation

A
  1. Can cause mutations in living organisms

2. Can damage cells & tissue

30
Q

Contamination

A

When the radioactive source is on/in the object (mixing)
•A contaminated object will be radioactive for as long as the source is on/in it
• Once an object is contaminated the radiation can’t be blocked from it
• Can be very difficult to remove all of the contamination

31
Q

Irradiation

A

When an object is EXPOSED to a source of radiation OUTSIDE THE OBJECT
• Doesn’t cause the object to become radioactive
• Can be blocked with suitable shielding
• Stops as soon as the source is removed

32
Q

Isotopes

A

Atoms with the same number of protons but different number of neutrons

33
Q

Is it possible to have gamma radiation emitted only?

A

NO!

34
Q

What happens when radiation (beta/gamma) enter the body?

A

Collides with molecules in cells ⮕ collisions cause ionisation ⮕ damages/destroys molecules

35
Q

What is background radiation?

A

Radiation that is always present around us in the environment

36
Q

Measuring radiation practical

A
  1. Use GM tube and counter to measure background radiation over a 1 minute period
  2. Repeat 3 times & calculate an average
  3. Place radioactive source FIXED DISTANCE away from tube, take reading over another 1 minute interval
  4. Take absorbers (paper, different thicknesses of aluminium & lead), place them between source & tube one at a time & take readings over a 1 minute interval
  5. If count over the interval falls to background levels, all the radiation has been absorbed
37
Q

Safety precautions during radiation practical

A
  1. Radioactive sources should be kept in a lead-lined box when not in use
  2. Only picked up using long-handled tongs/forceps
  3. Don’t point them at anyone, keep a safe distance from them
38
Q

Another name for atomic number

A

Proton number

39
Q

Another name for mass number

A

Nucleon number

40
Q

Uses of radiation

A
  1. Smoke detectors
  2. Medical tracers
  3. Treating cancer (radiotherapy)
  4. Sterilising food & equipment
  5. Thickness gauges
  6. Carbon dating
41
Q

How do smoke detectors work?

A
  1. Detector contains radioactive isotope emitting alpha particles
  2. Alpha particles ionise air inside detector: small current can flow
  3. Smoke enters detector, alpha particles absorbed, current no longer flows: triggers alarm
42
Q

How do thickness gauges work?

A
  1. Direct beta source through the stuff being made (e.g. paper)
  2. Put detector on other side connected to a control unit
  3. When detected radiation level changes, paper is coming out too thick/thin
43
Q

How do medical tracers work?

A
  • Added to blood to check blood flow around the body & search for clots
  • Usually beta or gamma source with a short half life
44
Q

Process of nuclear fission

A
  1. Uranium nucleus gets hit by slow moving neutron which gets absorbed
  2. Nucleus becomes unstable
  3. Splits into two daughter nuclei and two or three other neutrons
  4. Energy is released as well
45
Q

Does the neutron being absorbed in nuclear fission have to be fast or slow?

A

SLOW!

Only when it’s slow can it get absorbed by the uranium nucleus

46
Q

What type of energy is released in nuclear fission?

A

Kinetic

47
Q

How does fission lead to a chain reaction?

A

Nucleus splits, releasing two/three neutrons which are absorbed by different uranium nuclei, causing a chain reaction

48
Q

What does the moderator do?

A

Moderates (i.e. slows down) the speed of neutrons so that they can collide with the uranium nuclei at the correct speed.

49
Q

Examples of moderators

A

Water (best & simplest), graphite

50
Q

What do control rods do?

A

Absorb neutrons/stops neutrons from causing further fission

Primarily a safety feature

51
Q

Lowering control rods…

A

Absorbs more neutrons, reducing speed of reaction

52
Q

Raising control rods…

A

Absorbs less neutrons and increases speed of reaction

53
Q

What are control rods typically made of?

A

Boron

54
Q

What is shielding made of?

A

Thick concrete

55
Q

What does shielding do?

A

Absorbs ionising radiation and neutrons, both of which could cause damage to body tissue

56
Q

How can ‘low-level’/slightly radioactive waste be disposed?

A

Burying it in secure landfill sites

57
Q

How is high-level waste disposed?

A

Sealed into glass blocks which are then sealed into metal canisters (thick shielding), then buried deep underground

58
Q

Precautions for sites for disposing radioactive waste

A
  1. Geologically stable (not prone to earthquakes). Big movements in rock could disturb canisters and allow radioactive material to leak out
  2. Not near groundwater/water sources

Physics GCSE (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions