What is radiation emitted by
Unstable nuclei
Why do nuclei emit radiation
to reduce their energy and become more stable
How many types of radiation are there
3
Name the three types of radiation
alpha, beta, gamma
Alpha charge
Positive/2+
Gamma charge
0/neutral
Beta charge
1-/negative
Alpha mass
Largest out of the three
Beta mass
In the middle, much smaller than alpha
Gamma mass
No mass
Alpha range
few cm (5)
Beta range in air
20-30cm
Gamma range in air
infinite
Alpha radiation
2 protons and 2 neutrons (Helium nucleus)
Beta radiation
high energy fast moving electron
Gamma radiation
Electromagnetic wave
Alpha blocked by
Paper or a few cm of air
Beta blocked by
few mm aluminium
Gamma blocked by
few cm lead
Activity
The amount of nuclear decays per second
Activity unit
Becquerels (Bq)
Activity equation
A=N/t
Background radiation
Radiation present in everyday situations
Sources of background radiation
radon gas from the ground, food and drink, buildings, cosmic rays, medical and nuclear power-plants
Half life
length of time required for half of the radioactive atoms in a sample to decay`
Absorbed does
D=Energy/Mass
Absorbed does unit
Grays Gy
Equivalent does
D x weighting factor
Equivalent unit
Sv
Equivalent does rate
Amount fo ed absorbed each second
EDR equation
H. = H/t
Uses of radiation
smoke detectors, thickness control, sterilising, radioactive dating, radioactive tracers, checking welds, and cancer treatment
Nuclear fission
A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
Chain reaction
A series of reactions in which the product or by-product of the reaction initiates further reaction.
Nuclear fusion
a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
Average background radiation fo public
2.2 MSV
EDR unit
Sv/s
Effective does limit for piblic
1 mSv
effective does limit for radiatino worker
20mSv
what is ionisation
the addition or removal of one or more electrons from an atom turning it into an ion with a positive or negative charge.