AS &A Level PHYSICS Stephen Pople OXFORD UNIVERSITY PRESS OXFORD UNIVERSITY PRESS Great Clarendon Street, Oxford OX2 6DP Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide in Oxford NewYork Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries © Stephen Pople 2001 The moral rights of the author have been asserted Database right Oxford University Press (maker) First published 2000 Second edition 2001 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organisation. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the above address You must not circulate this book in any other binding or cover and you must impose this same condition on any acquirer British Library Cataloguing in Publication Data Data available ISBN-13: 978-0-19-915078-6 10 9 8 7 6 54 3 Designed and typset in Optima by Hardlines, Charlbury, Oxfordshire UK Printed in Great Britain by Bell & Bain Ltd, Glasgow CONTENTS How to use this book 4 E4 Circular orbits and rotation 72 Specification structures 4 E5 Magnets and currents 74 Pathways 6 E6 Magnetic fields and forces 76 How to revise 8 E7 Electromagnetic induction 78 Success in examinations 9 E8 Charged particles in motion 80 Practical assessment 10 Carrying out investigations 11 HEAT AND GASES Coping with coursework 12 F1 Liquid and gas pressure 82 Key Skills 13 F2 Temperature 84 Answering the question 14 F3 Internal energy, heat, and work 86 F4 The behaviour of gases 88 UNITS AND MEASUREMENTS F5 Atoms and molecules in motion 90 A1 Units and dimensions 18 F6 Kinetic theory 92 A2 Measurements, uncertainties, and graphs 20 F7 Heat transfer 94 MECHANICS ATOMIC, NUCLEAR, AND PARTICLE PHYSICS B1 Motion, mass, and forces 22 G1 The nuclear atom 96 B2 Work, energy, and power 24 G2 Radiation and decay 98 B3 Analysing motion 26 G3 Nuclear energy 100 B4 Vectors 28 G4 Quantum theory 102 B5 Moments and equilibrium 30 G5 Applications of quantum theory 104 B6 Motion and momentum 32 G6 Particle physics- 1 106 B7 Work, energy, and momentum 34 G7 Particle physics-2 108 B8 More motion graphs 36 G8 Particle physics-3 11 0 . Aircraft principles 37 B9 Fluid flow 38 APPLICATIONS AND OPTIONS B10 Cars in motion 40 H1 Astrophysics- 1 112 B11 Circular motion 42 H2 Astrophysics- 2 114 B12 Cycles, oscillations, and SHM 44 H3 Cosmology 116 B13 Energy changes in oscillators 46 H4 Solids, stresses, and strains 118 Forced oscillations and resonance 47 H5 Materials- 1 120 H6 Materials-2 122 WAVES H7 Medical physics- 1 124 C1 Waves and rays 48 H8 Medical physics-2 126 C2 Moving waves 50 H9 Medical physics - 3 128 C3 Combining waves 52 H10 Telecommunications- 1 130 C4 Using mirrors and lenses- 1 54 H11 Telecommunications-2 132 C5 Using mirrors and lenses-2 56 H12 Turning points in physics 134 H13 Energy and the environment- 1 136 ELECTRICITY H14 Energy and the environment-2 138 01 Charges and circuits 58 H15 Earth and atmosphere 140 02 Current and resistance 60 H16 Electronics- 1 142 03 Analysing circuits 62 H17 Electronics-2 144 04 Alternating current 64 Self-assessment questions 146 ELECTRIC, GRAVITATIONAL, AND Self-assessment answers 151 MAGNETIC FIELDS Physical data 154 E1 Electric charges and fields 66 Equations to learn 155 E2 Capacitors and fields 68 Index 157 E3 Gravitation 70 How to use this book • If you are studying for an AS or A level in physics, start here! (If you are not aiming for one of these qualifications, you can use this book as a general reference for physics up to advanced level: there is an index to help you find the topic(s) you require.) • Obtain a copy of the specification you are going to be examined on. Specifications are available from the exam boards' websites: www.aqa.org.uk; www.edexcel.org.uk; www.ocr.org.uk. • With the table below as a starting point, make your own summary of the content of the specification you will be following. • Use the pathways on pages 6 and 7 to help match the material in this book with that required by your specification. • Find out the requirements for any coursework and the dates of your exams and plan your revision accordingly. Page 8 has some helpful advice. • Begin revising! The self-assessment questions on pages 146-151 will help you to check your progress. Note: • This book covers AS and A2 material for all the main specifications and therefore contains some sections that you will not require. • The material in this book is not divided up into AS and A2 because the level required may vary from one specification to another. • If your specification is not listed, most of the material you need will still be included in this book, but you will have to construct your own route through the book. Specification structures This table summarizes the six main AS and A level specifications. Satisfactory assessment in units 1-3 corresponds to an AS level pass. Satisfactory assessment in the AS units 1-3 and the A2 units 4-6 corresponds to an A level pass. In each column are listed the unit names and main subdivisions as given in the specification. The method of assessment in each unit is listed, together with the percentage of marks assigned to the entire AS or A level. Do check your specification for the latest information. AQA Physics A AQA Physics B Edexcel Physics Unit 1 Particles, radiation, and quantum Foundation physics (Module 1) Mechanics and radioactivity phenomena (Module 1) 1h 30m written exam on Module 1 (short 1h 20m written exam (short & long 1h 30m written exam on Module 1 (short answer & structured questions) structured questions) structured questions) AS 3S% A 17 .S% AS30% A 1S% AS30% A 1S% Unit 2 Mechanics and molecular kinetic theory Waves and nuclear physics (Module 2) Electricity and thermal physics - (Module2) 1h 30m written exam on Module 2 (short 1h 20m written exam (short & long 1h 30m written exam on Module 2 (short answer & structured questions) structured questions) <I> "2 structured questions) AS 3S% A 17.S% AS30% A 1S% ::s AS30% A 1S% "<' Unit 3 Current electricity and elastic properties of Experimental work (Module 3) Topics solids (Module 3) 2h practical exam One of: 1h 30m written exam on Module 3 (short AS30% A 1S% Astrophysics structured questions) Solid materials AS 2S% A 12.S% Nuclear and particle physics 1h 30m practical exam OR Coursework Medical physics AS 1S% A 7.S% AS 1S% A 7.S% 1h 20m written exam (structured questions) AS20% A 10% 4Sm practical exam AS20% A 10% Unit4 Waves, fields, and nuclear energy Further physics (Module 4) Waves and our Universe (Module4) 1h 30m written exam on Module 1 (short 1h 20m written exam (short & long 1h 30m written exam on Module 4 answer & structured questions) structured questions) (multiple-choice and structured questions) A1S% A 1S% A1S% UnitS Nuclear instability (Module 5) Fields and their applications (Module 5) Fields and forces Options (Module 6) 2h written exam (synoptic assessment: 1h written exam One of: structured questions & comprehension A7.S% - Astrophysics question) 1h 30m practical exam Medical physics A20% A7.S% <I> "2 Applied physics ::s Turning points in physics <N Electronics 1h 30m written exam on Modules S & 6 (structured questions) A 10% 1h 30m practical exam OR Coursework AS% AS% Unit 6 2h written exam on Modules 1-S (structured Experimental work (Module 6) Synthesis synoptic questions) 3h practical exam & synoptic assessment in 2h written exam (synoptic assessment: A20% a practical context passage analysis & long structured A1S% questions) A20% 4 Specification structures Edexcel Physics (Salters Horners) OCR Physics A OCR Physics B (Advancing Physics) Unit 1 Physics at work, rest, and play Forces and motion Physics in action The sound of music 1h 30m written exam Communication Technology in space AS30% A 15% Designer materials Higher, faster, stronger 1h 30m written exam 1h 30m written exam AS 33.4% A 16.7% AS 33.3% A 16.7% - Unit 2 Physics for life Electrons and photons Understanding processes ·c":' Good enough to eat 1h 30m written exam 1h 30m written exam Digging up the past AS 30% A 15% AS 36.6 A 18.3% :I Spare part surgery <V"l 1h 30m written exam AS 33.3% A 16.7% Unit 3 Working with physics Wave properties/experimental skills Physics in practice Two laboratory practical activities and an 1h written exam Coursework out-of-school visit. AS20%A 10% AS 30%A 15% Coursework 1h 30m practical exam OR Coursework AS 33.3% A 16.7% AS20% A10% AS20% A10% Unit4 Moving with physics Forces, fields, and energy Rise and fall of the clockwork Universe Transport on track 1h 30m written exam Models and rules The medium is the message A15% Matter in extremes Probing the heart of matter 1h 20m written exam 1h 30m written exam A 10.8% A 15% Practical investigation Coursework A 7.5% UnitS Physics from creation to collapse Options in physics Field and particle pictures Two-week individual practical project One of: Fields - Coursework Cosmology Fundamental particles ·c":' A 10% Health physics 1h 1Om written exam :I Reach for the stars Materials A 10.8% <N Build or bust? Nuclear and particle physics Research report 1h written exam Telecommunications Coursework A10% 1h 30m written exam A 7.5% A15% Unit6 Exploring physics Unifying concepts in physics/experimental Advances in physics 1h 30m written exam (synoptic questions) skills 1h 30m written exam A15% 1h written exam A15% A10% Coursework A10% 1h 30m practical exam A10% What are ... . . . short-answer questions? These questions will require just a few words or sentences as answers . . . . structured questions? This type of question is broken up into smaller parts. Some parts will ask you to define or show you understand a given term; explain a phenomenon or describe an experiment; plot sketch graphs or obtain information from given graphs; draw labelled diagrams or indicate particular features on a given diagram. Other parts will lead you to the solution of a complex problem by asking you to solve it in stages . .. . comprehension questions? In these questions you will be given a passage (short or extended) on a topic and then tested on your understanding of the topic and the scientific concepts in it. ...d ata-analysis questions? In this type of question you will be given data in a variety of forms: graphs, tables, in text, as a list. You will then be asked to analyse the data to derive new results or information and may be asked to link the results with explanations of the scientific principles involved . . . . synoptic questions? When answering these you will have to apply physics principles or skills in contexts that are likely to be unfamiliar to you. Some questions will require you to show that you understand how different aspects of physics relate to one another or are used to explain different aspects of a particular application. Questions of this type will require you to draw on the knowledge, understanding, and skills developed during your study of the whore course. 20% of the A level marks are allocated to synoptic questions. Specification structures 5 , Pathways The following pathways identify the main sections in the book that relate to the topics required by each specification. Note: • You will not necessarily need all the material that is given in any section. • There may be material in other sections (e.g. applications) that you need to know. • You should identify the relevant material by referring to the specification you are following. • If this is your own copy of the book, highlight all the relevant topics throughout the book. AQA Physics A AQA Physics B Edexcel Physics B (Salters Horners) The Edexcel Salters Horners course structure is thematic. Concepts are covered as they are required for explanations within a given theme. It is therefore not possible to summarize the content in the same way as the other specifications. If you are following this course you should: • use the index and the Salters Horners specification to link the learning outcomes required to the pages on which the topics appear • note the sections where relevant information appears as you cover them in the modules • highlight the relevant material if this copy of the book is your own property. 6 Pathways Edexcel Specification A OCR Physics A OCR Physics B (Advancing Physics) Pathways 7 How to revise FIND A QUIET CORNER Find the conditions in which you c~n revise most efficiently. Many people think they can revise in a noisy busy atmosphere T~ere is no one method of revising which works for everyone. -most cannot! Any distraction lowers concentration. Revising It 1s therefore 1mportant to discover the approach that suits you in front of a television doesn't generally work! best. The following rules may serve as general guidelines. GIVE YOURSELF PLENTY OF TIME Leaving everything until the last minute reduces your chances of success. Work will become more stressful, which will reduce your concentration. There are very few people who can revise everything 'the night before' and still do well in an examination the next day. KEEP TRACK Use checklists and the relevant examination board specification to keep track of your progress. The Pathways and Specification Outlines in the previous section will help. Mark off topics you PLAN YOUR REVISION TIMETABLE have revised and feel confident with. Concentrate your revision You need to plan you revision timetable some weeks before the on things you are less happy with. examination and make sure that your time is shared suitably between all your subjects. MAKESHORTNOTES,USECOLOURS Once you have done this, follow it-don't be side-tracked. Revision is often more effective when you do something active Stick your timetable somewhere prominent where you will rather than simply reading material. As you read through your keep seeing it-or better still put several around your home! notes and textbooks make brief notes on key ideas. If this book is your own property you could highlight the parts of pages that are relevant to the specification you are following. Concentrate on understanding the ideas rather than just memorizing the facts. PRACTISE ANSWERING QUESTIONS As you finish each topic, try answering some questions. There are some in this book to help you (see pages 146-151). You should also use questions from past papers. At first you may need to refer to notes or textbooks. As you gain confidence you will be able to attempt questions unaided, just as you will in the exam. ADJUST YOUR LIFESTYLE RELAX Make sure that any paid employment and leisure activities Concentrated revision is very hard work. It is as important to allow you adequate time to revise. There is often a great give yourself time to relax as it is to work. Build some leisure temptation to increase the time spent in paid employment time into your revision timetable. when it is available. This can interfere with a revision timetable and make you too tired to revise thoroughly. Consider carefully GIVE YOURSELF A BREAK whether the short-term gains of paid employment are preferable When you are working, work for about an hour and then take a to the long-term rewards of examination success. short tea or coffee break for 15 to 20 minutes. Then go back to another productive revision period. 8 How to revise Success in examinations KEYWORDS How you respond to a question can be helped by studying the following, which are the more common key words used in EXAMINATION TECHNIQUE examination questions. The following are some points to note when taking an examination. Name: The answer is usually a technical term consisting of one • Read the question carefully. Make sure you understand or two words. exactly what is required. • If you find that you are unable to do a part of a question, do not List: You need to write down a number of points (often a single give up. The next part may be easier and may provide a clue to word) with no elaboration. what you might have done in the part you found difficult. Define: The answer is a formal meaning of a particular term. • Note the number of marks per question as a guide to the depth of response needed (see below). What is meant by ... ? This is often used instead of 'define'. • Underline or note the key words that tell you what is State: The answer is a concise word or phrase with no required (see opposite). elaboration. • Underline or note data as you read the question. • Structure your answers carefully. Describe: The answer is a description of an effect, experiment, • Show all steps in calculations. Include equations you use and or (e.g.) graph shape. No explanations are required. show the substitution of data. Remember to work in Sl units. Suggest: In your answer you will need to use your knowledge • Make sure your answers are to suitable significant figures and understanding of topics in the specification to deduce or (usually 2 or 3) and include a unit. explain an effect that may be in a novel context. There may be • Consider whether the magnitude of a numerical answer is no single correct answer to the question. reasonable for the context. If it is not, check your working. • Draw diagrams and graphs carefully. Calculate: A numerical answer is to be obtained, usually from • Read data from graphs carefully; note scales and prefixes data given in the question. Remember to give your answer to a on axes. suitable number of significant figures and give a unit. • Keep your eye on the clock but don't panic. Determine: Often used instead of 'calculate'. You may need to • If you have time at the end, use it. Check that your obtain data from graphs, tables, or measurements. descriptions and explanations make sense. Consider whether there is anything you could add to an explanation or Explain: The answer will be extended prose. You will need to description. Repeat calculations to ensure that you have use your knowledge and understanding of scientific not made a mistake. phenomena or theories to elaborate on a statement that has been made in the question or earlier in your answer. A question DEPTH OF RESPONSE often asks you to 'state and explain ... '. Look at the marks allocated to the question. Justify: Similar to 'explain'. You will have made a statement This is usually a good guide to the depth of the answer and now have to provide a reason for giving that statement. required. It also gives you an idea how long to spend on the question. If there are 60 marks available in a 90 minute exam, Draw: Simply draw a diagram. If labelling or a scale drawing is your 1 mark should be earned in 1.5 minutes. needed, yo"u will usually be asked for this, but it is sensible to provide labelling even if it is not asked for. Explanations and descriptions Sketch: This usually relates to a graph. You need to draw the If a 4 mark question requires an explanation or description, you general shape of the graph on labelled axes. You should include will need to make four distinct relevant points. enough quantitative detail to show relevant intercepts and/or You should note, however, that simply mentioning the four whether the graph is exponential or some inverse function, points will not necessarily earn full marks. The points need to for example. be made in a coherent way that makes sense and fits the context and demands of the questions. Plot: The answer will be an accurate plot of a graph on graph paper. Often it is followed by a question asking you to Calculations 'determine some quantity from the graph' or to 'explain its In calculation questions marks will be awarded for method and shape'. the final answer. Estimate: You may need to use your knowledge and/or your experience to deduce the magnitude of some quantities to arrive In a 3 mark calculation question you may obtain all three marks at the order of magnitude for some other quantity defined in if the final answer is correct, even if you show no working. the question. However, you should always show your working because • sometimes the working is a requirement for full marks Discuss: This will require an extended response in which you • if you make an error in the calculation you cannot gain any demonstrate your knowledge and understanding of a given topic. method marks unless you have shown your working. Show that: You will have been given either a set of data and a final value (that may be approximate) or an algebraic equation. In general in a 3 mark calculation you earn You need to show clearly all basic equations that you use and 1 mark for quoting a relevant equation or using a suitable all the steps that lead to the final answer. method 1 mark for correct substitution of data or some progress REVISION NOTE toward the final answer In your revision remember to 1 mark for a correct final answer given to suitable significant • learn the formulae that are not on your formula sheet figures with a correct unit. • make sure that you know what is represented by all the symbols in equations on your formula sheet. Errors carried forward If you make a mistake in a cakulation and need to use this incorrect answer in a subsequent part of the question, you can still gain full marks. Do not give up if you think you have gone wrong. Press on using the data you have. Success in examinations 9 Practical assessment PRACTICAL SKILLS There are four basic skill areas: Your practical skills will be assessed at both AS and A level. Planning Make sure you know how your practical skills are going to Implementing be assessed. Analysing You may be assessed by Evaluating • coursework The same skills are assessed in both practical examinations • practical examination and coursework. The method of assessment will depend on the specification you are following and the choice of your school/college. You may be required to take GENERAL ASSESSMENT CRITERIA • two practical examinations (one at AS and one at A level) You will be assessed on your ability to • two coursework assessments • identify what is to be investigated • one practical examination and one coursework assessment. • devise a hypothesis or theory of the expected outcome • devise a suitable experiment, use appropriate resources, PRACTISING THE SKILLS and plan the procedure Whichever assessment type is used, you need to learn and • carry out the experiment or research practise the skills during your course. • describe precisely what you have done • present your data or information in an appropriate way Specific skills • draw conclusions from your results or other data You will learn specific skills associated with particular topics as • evaluate the uncertainties in your experiment a natural part of your learning during the course. Make sure • evaluate the success or otherwise of the experiment and that you have hands-on experience of all the apparatus that is suggest how it might have been improved. used. You need to have a good theoretical background of the topics on your course so that you can • devise a sensible hypothesis GENERAL SKILLS • identify all variables in an experiment The general skills you need to practise are • control variables • the accurate reporting of experimental procedures • choose suitable magnitudes for variables • presentation of data in tables (possibly using spreadsheets) • select and use apparatus correctly and safely • graph drawing (possibly using IT software) • tackle analysis confidently • analysis of graphical and other data • make judgements about the outcome. • critical evaluation of experiments PRACTICAL EXAMINATION Carrying out experiments The form of the examination varies from one examination board When making observations and tabulating data remember to to another, so make sure you know what your board requires you • consider carefully the range and intervals at which you make to do. Questions generally fall into three types which fit broadly your observations into the following categories: • consider the accuracy to which it is reasonable to quote your You may be required to observations (how many significant figures are reasonable) • examine a novel situation, create a hypothesis, consider • repeat all readings and remember to average variables, and design an experiment to test the hypothesis • be consistent when quoting data • examine a situation, analyse data that may be given to you, • tabulate all data (including repeats and averages) and evaluate the experiment that led to the data remembering to give units for all columns • obtain and analyse data in an experiment which has been • make sure figures are not ambiguous. devised by the examination board. When deriving data remember to In any experiment you may be required to determine • work out an appropriate unit uncertainties in raw data, derived data, and the final result. • make sure that the precision is consistent with your raw data. Designing experiments and making hypotheses When drawing graphs remember to Remember that you can only gain marks for what you write, so • choose a suitable scale that uses the graph paper fully take nothing for granted. Be thorough. A description that is too • label the axes with quantity and unit long is better than one that leaves out important detail. • mark plotted points carefully with a cross using a sharp pencil Remember to • draw the best straight line or curve through the points so that • use your knowledge of AS and A level physics to support the points are scattered evenly about the line. your reasoning • give quantitative reasoning wherever possible When analysing data remember to • draw clear labelled diagrams of apparatus • use a large gradient triangle in graph analysis to improve • provide full details of measurements made, equipment used, accuracy and experimental procedures • set out your working so that it can be followed easily • be prepared to state the obvious. • ensure that any quantitative result is quoted to an accuracy that is consisted with your data and analysis methods A good test of a sufficiently detailed account is to ask yourself • include a unit for any result you obtain. whether it would be possible to do the experiment you describe without needing any further infomation. 10 Practical assessment