1. 1

2. X C 2 Mass Number A Atomic Number Z 14 6
Z = number of protons
A = number of nucleons
N = A – Z = number of neutrons C 14 6
Also known as Carbon-14 , this element has 6 protons and 8 neutrons.

3. 3 time=0 1 half-life 2 half-lives 3 half-lives
t= years 5730x2=11,460yrs 5730x3=17,190yrs
m= x1/2= 64 g 64x1/2= 32 g 32x1/2= 16 g
Mass of Carbon-14, grams
Time, years

4. 4 Amount = (Initial Amount) = A0 2no of half-lives 2n
where n is the number of half-lives
Eg. How much radioactive material will there be after 30 days if you start with 1000g and the half-life is 6 days?
n = 5 A = A0/2n
A0 = = 1000/25
= 1000/32
= g
No of half-lives = total time/half-life
= 30/6
= 5

5. X Y  5 Alpha Decay,  A Z A-4 Z-2 4 2 proton neutron Alpha particle
Daughter nucleus X A Z Y
A-4
Z-2  4 2

6. 6
proton
Neutron
Electron
Beta Decay, 
Beta particle
Daughter nucleus X A Z
Z+1  -1
1 neutron becomes 1 proton and 1 electron

7. 7
proton
neutron
Gamma Decay, 
Gamma ray X* A Z  X

8. 8

9. 9 Normal Material Normal Molecule Affected Molecule Alpha radiation
Gamma radiation
Gamma ray still travelling

10. 10 Absorbed = energy absorbed Dose mass of body Unit is the Gray, Gy
Each person absorbs 20 J of ionising radiation
Mass = 60kg mass = 25kg
Absorbed = energy absorbed
Dose mass of body
Unit is the Gray, Gy
AD = En/mass
= 20/60
= 0.33 Gy
AD = En/mass
= 20/25
= 0.8 Gy

11. 11 DE = AD x QF Dose Equivalent = absorbed dose x quality factor
Unit is the Sievert, Sv
DE = AD x QF
Radiation Quality Factor
Alpha 20
Neutrons 5
Beta 1
Gamma 1
For example, an absorbed dose of 0.33 Gy has a dose equivalent of:
DE = AD x QF
= 0.33 x for beta particles
= 0.33 Sv
DE = AD x QF
= 0.33 x 20 for alpha particles
= 6.6 Sv

12. Duration of dose equivalent (acute/chronic)12
Dose equivalent (mSv)
Duration of dose equivalent (acute/chronic)
Effect
15000
acute and chronic
Fatal effects in all cases
10000
Likely immediate fatal illness
2000
Threshold for immediate, fatal radiation sickness
1000
chronic
Increased likelihood of later development of cancer
acute
Threshold for immediate, non-fatal radiation sickness
100
Increasing likelihood of cancer 50
Maximum annual dose for any worker.
Lowest dose at which cancers may be caused in adults 20
Average limit per year for workers in the nuclear industry, uranium and mineral sands miners, and medical workers