MACMILLAN MASTER SERIES

Transcription

1 MASTERING PHYSICS

2 MACMILLAN MASTER SERIES Banking Basic Management Biology British Politics Business Communication Business Microcomputing Chemistry COBOL Programming Commerce Computer Programming Computers Data Processing Economics Electronics English Grammar English Language English Literature Financial Accounting French French 2 German Hairdressing Italian Keyboarding Marketing Mathematics Modern British History Modern World History Nutrition Office Practice Pascal Programming Physics Principles of Accounts Spanish Spanish 2 Statistics Statistics with your Microcomputer Study Skills Typewriting Skills Word Processing

3 MASTERING PHYSICS THIRD EDITION H. J.P. KEIGHLEY F. R. McKIM A. CLARK M. J. HARRISON M MACMILLAN

4 Text H. J.P. Keighley, F. R. McKim, A. Clark and M. J. Harrison, 1982, 1984, 1986 Figures The Macmillan Press Ltd 1982, 1984, 1986 All rights reserved. No reproduction, copy or transmission of this publication may be made without written permission. No paragraph of this publication may be reproduced, copied or transmitted save with written permission or in accordance with the provisions of the Copyright Act 1956 (as amended). Any person who does any unauthorised act in relation to this publication may be liable to criminal prosecution and civil claims for damages. First edition 1982 Reprinted 1982, 1983 Revised edition 1984 Third edition 1986 Published by MACMILLAN EDUCATION LTD Houndmllls, Basingstoke, Hants RG21 2XS and London Companies and representatives throughout the world Typeset by TecSet Ltd, Sutton, Surrey ISBN DOI / ISBN (ebook)

5 CONTENTS Preface to the First Edmon Preface to the Revised Edition Preface to the Third Edition Acknowledgements xiii xiv XV xvi I. MECHANICS 1 Fundamental concepts 1.1 Length Metric prefixes Force Measurement of force Load-extension graphs Mass Weight Measuring time Volume Measuring volume Density Air density 10 2 Pressure 2.1 The concept of pressure Pressure in liquids The pressure due to a column of liquid Upthrust Measuring pressure Atmospheric pressure A simple barometer The aneroid barometer Airliners and spacesuits 22 3 Vectors 3.1 Addition of physical quantities An experiment on addition of forces 24 4 Motion 4.1 Definition of terms Newton's frrst law of motion Newton's second law of motion 31

6 CONTENTS 4.4 The unit of force, the newton Newton's third law of motion Momentum and impulse Conservation of momentum Rocket and jet motors Acceleration in free fall Frictional forces in solids The importance of friction Uniformly accelerated motion Motion graphs 42 5 Levers and centres of 5.1 Levers in everyday life 44 gravity 5.2 An experiment to investigate the turning effect of a force Centre of gravity Determining the position of the centre of gravity Stability Couples 50 6 Work, energy and power 6.1 Some definitions Various forms of energy Electrical energy Kinetic energy (KE) Potential energy (PE) Conservation of energy Heat energy Energy conversion in a power station Power The energy crisis 59 7 Machines 7.1 Introduction An experiment with pulleys The inclined plane Levers 65 II. HEAT AND MOLECULAR STRUCTURE 8 Heat energy 8.1 Introduction Frictional heating Specific heat capacity Specific heat capacity by an electrical method A basic equation 72

7 8.6 Different specific heat capacities 72 9 Expansion 9.1 Demonstration of expansion Large forces involved in the expansion of a solid Expansion - friend or foe? linear expansivity Bimetallic strip Calibration of a mercury thermometer The clinical thermometer Molecular explanation of expansion Propertiesof~sand 10.1 The molecular theory of molecular structwe matter Molecules in solids Molecules in liquids The size of a molecule Molecules in gases Diffusion Brownian movement Boyle's law for a gas at constant temperature Gas pressure law at constant volume Charles' law for a gas at constant pressure The kinetic theory for gases The transfer of heat enew 11.1 Introduction Conduction An explanation of conduction Convection Radiation Reflection and refraction of radiation Emitters and absorbers of radiation The vacuum flask Heat problems in supersonic aircraft and satellites The greenhouse effect Hot water and central heating 103 vii

8 CONTENTS 12 Change of state 12.1 Latent heat 105 III. WAVE MOTION, LIGHT AND SOUND 12.2 Measuring specific latent heat When a liquid evaporates, it cools Distinction between 108 evaporation and boiling 12.5 The body's cooling system and refrigerators An increase in pressure lowers the melting point The binding of snowballs A decrease in pressure lowers the boiling point Pressure cookers Waves 13.1 Introduction Describing waves Transverse waves Longitudinal waves Observing and measuring 118 travelling waves 13.6 The wave equation Wave velocity Energy in waves Properties of travelling waves Standing waves Reflections and shadows 14.1 Rays of light Laws of regular reflection The image in a plane mirror Uses of plane mirrors Diffuse reflection Shadows Refraction 15.1 Introduction Refraction at an air-glass interface Refractive indices The reversibility of a ray of light Internal reflections 145

9 ix 15.6 Some applications of total internal reflection Real and apparent depths Thin lenses and cwved 16.1 Action of a lens 151 mirrors 16.2 Optical centre and focal point The power of a lens Measuring the focal length of a converging lens Images produced by lenses The action of a curved mirror The principal focus and focal length Uses of lenses and mirrors Optical instruments 17.1 The pinhole camera The camera with a lens The slide projector A radio telescope The electromagnetic 18.1 Visible light 164 spectrum 18.2 Detectors of light The extended spectrum Colour addition Colour subtraction Coloured objects seen in coloured lights Sound 19.1 Introduction Measurement of the frequency of sound waves Measuring the velocity of sound in air by an echo method Diffraction and interference of sound waves The pitch, loudness and quality of a musical note Absorption of sound waves Resonance 178

10 CONTENTS IV. ELECTRICITY, ATOMIC AND NUCLEAR PHYSICS 20 Magnetism 20.1 Properties of magnets The test for magnetism Making a magnet Induced magnetism Properties of soft iron and steel Magnetic fields Electrons and electron 21.1 Charging by friction 189 beams 21.2 Positive and negative charge Protons and electrons Charging by induction Ionisation Lightning and lightning conductors The cathode ray oscilloscope Electric circuits 22.1 Electric current Electric potential difference (voltage) Series and parallel circuits Current in series and parallel circuits Potential difference in series and parallel circuits Electrical resistance Combination of resistors The potential divider circuit Capacitors Magnetic effects of an 23.1 The magnetic field produced electric current by an electric current The magnetic field produced 23.3 by a solenoid Force on a current-carrying 216 conductor in a magnetic 217 field 23.4 The electric motor The moving-coil loudspeaker Energy and power from 24.1 Electrical power and energy 224 electrical sources 24.2 The mains supply Domestic wiring 226

11 24.4 Electrical connection to the mains supply The earth lead The kilowatt-hour Electromagnetic induction 25.1 Introduction The size of the induced e.m.f The direction of the induced current The alternating-current generator The direct-current generator An induced e.m.f. due to a changing current The transformer Step-up and step down transformers The efficiency of a transformer The distribution of electrical energy Radioactivity and the 26.1 The spark counter 244 atom 26.2 The Geiger-Miiller tube The diffusion cloud chamber The properties of the ionising radiations emitted from radioactive substances The nature of a, {3 and r radiation The mechanism of radioactive emissions Radioactive sources Radioactive decay Safety precautions and uses Nuclear Fission Electronics 27.1 Introduction The diode Bridge rectifier circuit Smoothing the output from a bridge rectifier A low voltage power supply LEDs, LDRs and thermistors 260 xi

12 CONTENTS 27.7 The transistor Using transistors Logic gates Combining logic gates The bistable An operational amplifier Operational amplifier as a switch 277 Questions 281 Answers to Questions 324 Index 328

13 xiii PREFACE TO THE FIRST EDITION The book aims to provide a concise, easily readable treatment of all the essential principles contained in 0-level physics courses. We have tried to present them with a directness and simplicity that will enable students to achieve maximum comprehension in the shortest possible time. Many diagrams have been included in the text as these are a great help in understanding physics and are especially useful in revision. Important laws and definitions are set in italic type. Sl units have been used throughout. Marlborough, 1982 H. J. P.K. F.R.McK. A. c. M.J.H.

14 xiv PREFACE TO THE REVISED EDITION In this edition we have added some worked examples and provided a.nswers to the questions at the end of the book. We have also extended one or two sections to provide more comprehensive coverage of the many different 0-level syllabuses, and have made a few minor changes in the text to improve its clarity. Marlborough, 1983 H.J.P.K. F. R. McK. A. C. M.J.H.

15 XV PREFACE TO THE THIRD EDITION We have changed the contents to bring the text into line with the proposed GCSE syllabuses. In particular, we have added a chapter on electronics, deleted topics such as electrolysis and most of the work on curved mirrors. We have added further worked examples and taken the, opportunity to make other changes in order to make the book as helpful as possible to students studying for GCSE. Marlborough, 1986 H.J.P.K. F. R. McK. A. C. M.J.H.

16 xvi ACKNOWLEDGEMENTS We gratefully acknowledge the following for supplying photographs which we have used to illustrate the part-title pages of the book: Part I The Columbia space shuttle being launched at Cape Canaveral (courtesy Space Frontiers Ltd). Part II The European Space Agency's European communications satellite (courtesy British Aerospace). Part III Approach and runway lights as seen from the flight deck of an aircraft (courtesy British Aerospace). Part IV The lights of Piccadilly Circus (courtesy United Kingdom Atomic Energy Authority). We are also grateful to Rex Fearures Ltd. for permission to reproduce the cover picture of Halley's Comet taken by the space probe Giotto. The European Space Agency used many physics laws and principles to get the space probe on course, to take the pictures and to transmit them back to Earth.