Physics - Radiation

What is radiation emitted by

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.