Notes on the different types of radioactivity (alpha, beta & gamma) and their uses in industry.

  • Created by: Hollie
  • Created on: 23-06-11 16:47

Nuclear Radiation

Atoms always contain:

  • Protons (+)
  • Neutrons (+-)
  • Electrons (-)

Atoms always have the same number of protons however isotopes have different numbers of neutrons

A radioactive substance always contains an unstable nuclei - they emit radiation and turn into other elements

Radioactive decay is a random process - it is not effected by external conditions

1 of 7

Alpha Radiation

Alpha is a helium nucleus made up of 2 protons and 2 neutrons

The particles are quite large which results in lots of collisions - this means they cannot penetrate far into a material

Stopped by:

  • Human skin
  • Paper
  • Few centimetres of air

Aplha particles are most dangerous if they are in the body - they are strongly ionising

Because of their positive charge they are deflected by electric and magnetic fields

2 of 7

Beta Radiation

A beta particle is a high speed electron found in the nucleus.

The particles are a lot smaller than alpha particles resulting in less collisions - this makes them less ionising and more penetrating

Stopped by:

  • Thin sheet of aluminium
  • Few metres of air

Beta particles have a negative charge

They are deflected by electric and magnetic fields oppositely to alpha particles

3 of 7

Gamma Radiation

Gamma radiation has a very short wavelength and is emitted from the nucleus.

As gamma rays are electromagnetic waves, they will travel a long time before colliding with an atom - not very ionising and very penetrating.

Stopped by:

  • Thick piece of lead ( few centimetres)
  • Several metres of concrete
  • Unlimited range of air

Gamma rays are not deflected by electric or magnetic fields.

4 of 7

Effects of Radiation on the Body

The danger of a radiaactive substance on the body depends on whether the radiation is in or outside of the body.

Inside the Body

  • Alpha is most dangerous - it is easily absorbed by the cells
  • Beta & Gamma aren't very dangerous - they are unlikely to be absorbed and would usually pass straight through the cells

Outside the Body

  • Alpha isn't very dangerous - it is unlikely to reach cells inside the body
  • Beta & Gamma are most dangerous - both are very penetrating so can penetrate the skin and damage the inside of cells.
5 of 7

Using Radiation in Industry

Radiation plays a big part in industry - depending upon its half life and the type of radiation it gives outs.

Examples include:

  • Smoke detectors (alpha)
  • Mearugin the thickness of materials, e.g. paper (beta)
  • Tracers for medical diagnosis (gamma/beta)
  • Sterilising medical treatment (gamma)
  • Killing cancer cells (gamma)

The half life of these radiations are very important. For example, medical tracers need a half life of only a few hours so that the radiation is not exposed to the body for too long.

6 of 7

Half- Life

The radioactivity of a material decreases gradually over time till it falls to nearly zero.

The idea of half life is used to measure how quickly this radioactivity decreases.

Definitions for half life:

The time in which it takes for the count rate of a substance to fall to half its initial value

The time it takes for the number of nuclei in an isotope to halve.

Example - a substance drops from 20 counts per minute to 10 counts in 15 days. The half life therefore is 15 days.

7 of 7





Miss KHP


A wonderful set of revision cards of radioactivity. They can be used for all exam boards as they are a nice and simple and will help you understand it. You may decide to add them to your own revision cards and so this will save you time.



Very useful :)

Jack Baynes





Extremely helpful!!!



Students have been struggling to work as efficiently as they did in traditional classes ever since there was a rapid switch to online classes and the introduction of technology in the classroom. Even if taking classes online has some benefits, there are some drawbacks as well. To pass the class, however, one must attend all of the lectures and take the Online Course For Me. Thus, get in touch with us on Take My Class for the greatest exam help online to get high marks. We provide everything you require to help you pass your online classes with the highest grades. Let's get going immediately.

Katie's cat


my cat disapproves with miss khp

Similar Physics resources:

See all Physics resources »See all Radioactivity resources »