7 Radioactivity Flashcards
1
Q
Alpha particle
A
- What: 2 protons & 2 neutrons (helium nucleus)
- Charge: +2
- Mass: 4
- Speed: Slow
- Penetration: Paper/Skin
- Ionising: Highly
2
Q
Beta particle
A
- What: single electron
- Charge: -1
- Mass: almost none
- Speed: Fast
- Penetration: Thin metal
- Ionising: Mildly
3
Q
Gamma particle
A
- What: Electromagnetic wave
- Charge: None
- Mass: None
- Speed: Speed of light
- Penetration: Thick lead (reduced by)
- Ionising: Weak
4
Q
Alpha decay
A
A
Initial –>
Z
A - 4
Final +
Z - 2
4
Alpha particle
2
5
Q
Beta minus decay
A
A
Initial –>
Z
A
Final +
Z + 1
0
Electron
-1
6
Q
Beta positive decay
A
A
Initial –>
Z
A
Final +
Z - 1
0
Positron
1
7
Q
Gamma decay
A
- Occurs alongside Alpha or Beta decay
- No change to mass/atomic number
8
Q
Neutron decay
A
A
Initial –>
Z
A - 1
Final +
Z
1
Neutron
0
- Non-ionising
- Causes atoms to become radioactive
9
Q
How to detect radiation
A
With Geiger−Müller detector
10
Q
Background radiation
A
- Small amount of constant radiation that is around us
- Natural sources:
- Cosmic radiation
- Rocks
- Food
- Building materials
- Man-made sources:
- Nuclear bombs
- Nuclear waste
- Medical
11
Q
Irradiation
A
- Object exposed to a radiation source, outside the object
- Object doesn’t become radioactive
- Can be blocked
- Stops as soon as the source is removed
12
Q
Contamination
A
- Radiation source in/on object
- Object will become radioactive
- Can’t be blocked
- Difficult to remove contamination
13
Q
Half-life
A
The average time taken for half of the radioisotopes in a sample to decay.
14
Q
Radioactivity unit
A
- Becquerels (Bq)
- The amount of radiation given out by a substance
- One Becquerel = One particle emitted per second
15
Q
Dangers of radiation
A
Can ionise atoms in living cells –> can cause mutations (mainly cancer)
