OCR A-Level Physics B H557
Planning
Implementing
Analysis
Evaluation
Practical Skills
Use of Apparatus and Techniques
Fundamental Data Analysis
Imaging and Signalling
Sensing
Mechanical Properties of Materials
Waves and Quantum Behaviour
Space, Time and Motion
Creating Models
Out Into Space
Our Place in the Universe
Matter: Very Simple
Matter: Hot or Cold
Electromagnetism
Charge and Field
Probing Deep Into Matter
Ionising Radiation and Risk
Ionising Radiation and Risk
The nature of ionising radiations
- 3 things to know
- Components 01, 02 and 03
Overview
Recall questions on ionisation, the nature, charge and mass of alpha, beta-minus and gamma radiation, their ionising power, absorbers and ranges, why gamma is never fully absorbed, deflection in a magnetic field, the spread of beta energies, beta-plus radiation, and gamma emission after alpha or beta decay.
What you need to know
Answer each one before you reveal it.
How do alpha, beta and gamma radiation behave in a magnetic field?
What is meant by ionisation?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is meant by ionisation?
Model answer
Ionisation is the removal of one or more electrons from a neutral atom or molecule, leaving it as a charged ion.
- 2
What is an alpha particle?
Model answer
An alpha particle is a helium nucleus, consisting of two protons and two neutrons, with a charge of +2e and a mass of about 4 u.
- 3
What is a beta-minus particle?
Model answer
A beta-minus particle is a fast-moving electron emitted from the nucleus when a neutron changes into a proton.
- 4
What is a gamma ray?
Model answer
A gamma ray is a high-energy photon of electromagnetic radiation emitted when a nucleus loses excess energy, and it carries no charge and no mass.
- 5
Rank alpha, beta and gamma radiation in order of ionising power, and explain the order.
Model answer
Alpha is the most ionising, then beta, then gamma, because the alpha particle carries twice the charge of a beta particle and moves comparatively slowly, so it interacts strongly with the electrons it passes.
- 6
State the absorber needed to stop each of alpha, beta and gamma radiation.
Model answer
Alpha radiation is stopped by a sheet of paper or a few centimetres of air, beta radiation by a few millimetres of aluminium, and gamma radiation is only reduced, needing several centimetres of lead to cut it substantially.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Ionising Radiation and Risk, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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