dangers and uses of radiation Compare the hazards associated with contamination and irradiation. Understand that suitable precautions must be taken to protect against radiation. Describe the uses of nuclear radiations for exploration of internal organs, and for control or destruction of unwanted tissue. Understand what background radiation is. past exam paper questions and answers at the end of the ppt

4.4.4 Nuclear fission and fusion (physics only) Aims: To understand that a large, unstable nucleus eg. U-235, can be split (the process of fission) by collision with a neutron, and that this process releases energy in the form of kinetic energy of the fission products. To recall that the fission of U-235 produces two daughter nuclei and a small number of neutrons (2-3). To understand that a chain reaction can be set up if the neutrons produced by one fission strike other U-235 nuclei. To understand that nuclear fusion is the joining of two light nuclei to form a heavier nucleus. In this process some of the mass may be converted into the energy of radiation. past exam questions and answers included at the end of ppt

alpha, beta. gamma Aims: To describe the nature of alpha and beta particles and gamma rays and recall that they may be distinguished in terms of penetrating power. To understand that ionising radiations can be detected using a Geiger-Muller detector. past exam paper questions and answers included

4.4.2.2 Nuclear equations Nuclear equations are used to represent radioactive decay. In a nuclear equation an alpha particle may be represented by the symbol: and a beta particle by the symbol: The emission of the different types of nuclear radiation may cause a change in the mass and /or the charge of the nucleus. For example: So alpha decay causes both the mass and charge of the nucleus to decrease. So beta decay does not cause the mass of the nucleus to change but does cause the charge of the nucleus to increase. Students are not required to recall these two examples. Students should be able to use the names and symbols of common nuclei and particles to write balanced equations that show single alpha (α) and beta (β) decay. This is limited to balancing the atomic numbers and mass numbers. The identification of daughter elements from such decays is not required. The emission of a gamma ray does not cause the mass or the charge of the nucleus to change. includes past exam paper questions and answers

4.4.2.3 Half-lives and the random nature of radioactive decay Aims: To understand that the activity of a radioactive source decreases over a period of time and is measured in becquerels. To recall the term ‘half-life’ and understand that it is different for different radioactive isotopes. To use the concept of half-life to carry out simple calculations on activity. past exam question and answers at the end of the ppt

Aims: To describe the structure of an atom in terms of protons, neutrons and electrons and use symbols such as C14 to describe particular nuclei. To understand the terms atomic (proton) number, mass (nucleon) number and isotope. To understand that alpha and beta particles and gamma rays are ionising radiations emitted from unstable nuclei in a random process. Past exam paper questions and answers included at the end of the power point

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