Learner Guide. Cambridge O Level Physics

Learner Guide

Cambridge O Level

Physics

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© Cambridge International Examinations 2015 Version 2.1

Contents

How to use this guide

... 3

Section 1: How will you be tested?

Section 2: Examination advice Section 3: What will be tested? Section 4: What you need to know Section 5: Useful websites

Section 6: Appendices

Section 1:

How will you be tested? ... 5

About the papers

About the theory papers About the practical papers

Section 2:

Examination advice ... 9

General advice

Section 3:

What will be tested? ... 13

Section 4:

What you need to know ... 15

How to use the table

Section 5:

Useful websites

... 43

Section 6:

Appendices ... 45

Symbols, units and defi nitions of physical quantities

How to use this guide

How to use this guide

The guide describes what you need to know about your Cambridge O Level Physics examination.

It will help you to plan your revision programme for the written examinations and will explain what we are looking for in the answers you write. It can also be used to help you to revise by using the tick boxes in Section 4 ‘What you need to know’, to check what you know and which topic areas of physics you have covered.

The guide contains the following sections:

Section 1: How will you be tested?

This section will give you information about the theory and practical examination papers.

Section 2: Examination advice

This section gives you advice to help you do as well as you can. Some of the ideas are general advice and some are based on the common mistakes that candidates make in exams.

Section 3: What will be tested?

This section describes the areas of knowledge, understanding and skills that we will test you on. It is particularly important to realise that most marks are awarded for understanding and skills and only approximately 30% of the total mark is for simple recall.

Section 4: What you need to know

This shows the syllabus content so that you can check: • which topics you need to know about

• details about each topic area in the syllabus • how much of the syllabus you have covered.

Section 5: Useful websites

• some useful websites that you might use.

Section 6: Appendices

This section covers other things you need to know, such as: • symbols, units and defi nitions of physical quantities

How to use this guide

Before you start:

Check with your teacher which practical paper you will be taking (Paper 3 or Paper 4).

Both of these papers are described in Section 1 and Section 3. You only need to read about one of them. The theory papers are the same for everyone and the theory is detailed in Section 2.

Section 1: How will you be tested?

Section 1: How will you be tested?

About the papers

You will be entered for three examination papers: two theory papers and one practical paper. You will take Paper 1 Multiple Choice, Paper 2 Theory and either Paper 3 Practical Test or Paper 4 Alternative to Practical. You need to ask your teacher which practical paper you are taking.

About the theory papers

The table gives you information about the theory papers.

Paper number and type

How long and how many marks?

What’s in the paper? What’s the % of the total examination? Paper 1 Multiple Choice 1 hour (40 marks) 40 multiple-choice questions 27.6 Paper 2 Theory 1¾ hours (75 marks)

Short answer and structured questions 51.7

Here is some more information about each paper.

Paper 1 Multiple Choice

You have to choose one of the four possible answers in each question.

The multiple-choice questions cover the entire syllabus, apart from Section 25 on Electronic Systems.

Paper 2 Theory

All answers are written in the spaces provided on the actual question paper. There are two sections.

Section A contains short structured questions where you may have to write a few words or sentences or make a calculation. You must answer all the questions.

Section B has three longer questions. Each question is worth 15 marks. You must answer two of the three questions, so take your time to read them carefully before choosing which questions to answer.

Section 1: How will you be tested?

About the practical papers

Just over 20 per cent of the marks for Cambridge O Level Physics are for practical work.

You will do one of the practical papers shown in the table, either Paper 3 or Paper 4. Your teacher will tell you which practical paper you will do.

Paper number and type How long and how many marks? What’s invovled? Paper 3 Practical Test 2 hours (30 marks)

You do a practical exam which is supervised by a teacher

Paper 4

Alternative to Practical

1 hour (30 marks)

You answer a written paper about practical work.

Here is some more detail about the practical papers. If you are unsure of anything, ask your teacher. EITHER

Paper 3 Practical Test

You do a practical exam, which is supervised by a teacher. You will carry out four short experiments. Section A contains three short questions and lasts 1 hour. Section B contains one question that takes 1 hour.

You are given instructions, which enable you to carry out the experiments. You will take readings and record them in a table. You need to use a sensible number of fi gures and give the unit in the heading. You will usually draw a graph and make some conclusions, commenting upon accuracy and on how to improve the experiment.

You may be asked to use the following techniques, amongst others: • recording current and potential difference and drawing circuit diagrams • ray tracing and drawing ray diagrams

• measuring temperature

• balancing (centre of mass and moments) • stretching of springs

• timing of oscillations.

Your experience of practical work during the course should enable you to handle the apparatus. Your teacher will be able to give you more examples and explain how to take readings and analyse the data.

Section 1: How will you be tested?

Paper 4 Alternative to Practical

This is a written paper, testing the same skills as Paper 3. There are usually four questions which test practical procedures in the physics laboratory.

You may be asked to:

• record readings from diagrams of apparatus, e.g. reading current from an ammeter • answer questions on the arrangement of apparatus

• complete tables of data

• draw conclusions from information

• answer questions about experimental data • plot a graph from a table of readings • interpret information from graphs • draw ray diagrams

• identify sources of error and suggest improvements in the experiment • suggest suitable apparatus for investigations.

You will need to do plenty of practical work during the course in order to score a good mark on this paper in the examination.

Section 2: Examination advice

Section 2: Examination advice

This section highlights some common mistakes made by candidates. They are collected under various subheadings to help you when you revise a particular topic.

General advice

• Thorough and careful revision is the best way to prepare for a physics examination.

• Make your revision productive by making it interesting and fun. Make notes, revision cards or mind maps. Revision should be an active process, i.e. you should be ‘doing things’, not just sitting and reading a book.

• Don’t try to learn it all in one go! Take regular breaks and review what you have learnt regularly.

• Learning equations is essential; put them on small pieces of paper and stick them somewhere you will see them every morning.

• Revise with a friend so you can test each other or try explaining the physics of a topic to a friend – as if you were a teacher!

• Working through past paper questions is the best way to complete your revision. This helps you to know the type and style of questions to expect in the examination.

• Try timed questions so you can learn to answer quickly. • Get your answers checked so you know you are correct!

• In Cambridge O Level Physics examinations you have to be able to complete a variety of tasks; always read the question carefully to make sure you have understood what you are expected to do.

Spelling

• The spelling of technical terms is important, so make sure your writing is legible as well as spelt correctly.

• Some words are very similar, such as refl ection and refraction, fi ssion and fusion. If we cannot tell which one you have written, then you will lose the mark. Make a list of technical terms and defi nitions in each section of the syllabus, checking the spellings carefully.

Descriptive answers

In descriptive answers, you should:

• Check the number of marks available and make sure you give suffi cient points. • Plan your answer fi rst so that you don’t repeat yourself or contradict yourself.

• Read your answer through carefully afterwards to check you have not missed out important words. • Read the question again to check you have answered the question asked.

• Use sketches and diagrams wherever you can to help your explanation.

• Add labels when referring to a diagram, e.g. point X, so that you can refer to it easily in your explanation. This can save many words and much confusion.

Section 2: Examination advice

Numerical answers

In numerical answers, you should:

• Quote any formulae you are going to use and show clearly all the steps in your working. It may be tempting to use your calculator and just write down the answer, but if you write down one fi gure wrongly then you may lose all the marks for the calculation. If we can see the formula and the numbers you have used then you will lose only a little credit. Some questions ask for a formula to be quoted; even if you get the right answer, failure to quote the formula will lose you a mark.

• Check the units are consistent, e.g. if the distance is given in km and the speed in m/s, then you must convert the km to m.

• Be careful when you are converting minutes and seconds: 1 minute 30 seconds is not 1.3 minutes and 150 seconds is not 1.5 minutes. These are common mistakes, so always double check any conversion of units of time.

• State the answer clearly at the end.

• Give your answer as a decimal to an appropriate number of signifi cant fi gures. Don’t leave your answer as a fraction unless specifi cally asked to do so.

• Check that you have given the unit of your fi nal answer.

• Look at your fi nal answer and see that it is reasonable. If you have calculated the cost of using an electrical appliance such as a kettle for a few minutes and found it to be hundreds of dollars, then check the powers of ten in your calculation.

Graphs

Plotting graphs can be tested in Papers 2, 3 or 4. When drawing graphs, you should:

• Remember to label the axes with both quantity (e.g. distance or d) and unit (e.g. metres or m). Then write it as distance/metres or even just d/m.

• Make sure the axes are the correct way round. You are usually told, for example, to plot distance on the

x-axis, so make sure you know that x is the horizontal axis!

• Make the scales go up in sensible amounts, i.e. 0, 5, 10… or 0, 2, 4… but not 0, 3, 6… or 0, 7, 14… • Make sure that the plotted points fi ll at least half the graph paper. This means if you can double the

scale and still plot all the points then you should double the scale.

• Check if you have been told to start the scales from the origin. If not, then think carefully about where to start the axes.

• When you are told to start the axes from a certain point (e.g. x = 1, y = 20) you must do so. You will lose a mark if you use a different point (e.g. the origin).

• Use a sharp pencil to plot the points and draw the line.

• Plot the points carefully. It is best to use small neat crosses. Every point will be checked by the examiner, and you will lose the mark if any are wrongly plotted.

• Draw either a straight line or a smooth curve. In physics we never join the dots! • Your line may not go through all the points – especially in the practical papers.

• Remember that a best fi t line (curve or straight) should have some points above and some points below the line.

Section 2: Examination advice

When taking readings from a graph, you should:

• Draw a large triangle when measuring the gradient of a line. It must be at least half the length of the line. Top tip: draw a triangle the full size of the graph! It is best to show the numbers on the sides of the triangle when fi nding the gradient.

• Always use points on the line, not your plotted points, when calculating the gradient.

• Draw a tangent to fi nd the gradient of a curve. Make sure it is at the right place on the curve. Again, use a large triangle.

• Make sure you read the scales correctly when reading a value from a graph. It may be that they are in mA rather than A or km rather than m.

When describing the shape of a graph, remember that:

• directly proportional means a straight line through the origin. There are two ways to check if quantities are directly proportional: – doubling one quantity will cause the other to double

– dividing one by the other will give the same result

i.e. if two quantities F and L are directly proportional then if you fi nd several values of F/L they should be the same

• if the straight line does not go through the origin, then it is just called a linear graph • inverse relationship means increasing one quantity will cause the other to decrease • if doubling one quantity causes the other to halve, then they are inversely proportional.

This can also be checked by:

– multiplying the two quantities together will give the same result

i.e. if two quantities F and L are inversely proportional then if you fi nd several values of F × L they should be the same.

Section 3: What will be tested?

Section 3: What will be tested?

We test you on three assessment objectives:

AO1 your knowledge (what you remember) and understanding (how you use what you know and apply it to unfamiliar situations)

AO2 how you handle information and solve problems AO3 your experimental skills

The theory papers test AO1 and AO2.

You should note that approximately 65% of the marks are for AO1 and of these only about half of these are for simple recall.

The practical papers test AO3.

The table shows you the range of skills you should try to develop.

Assessment objective

What this means Whatyou need to be able to do

AO1

Knowledge with understanding

remembering facts and applying these facts to new situations

• Use scientifi c ideas, facts and laws

• Know the meaning of scientifi c terms, e.g. centre of mass

• Know equations and defi nitions

• Use simple equations, e.g. speed = distance/time • Know about apparatus and how it works

• Know about symbols, quantities (e.g. mass and weight) and units (e.g. kg and N)

AO2 Handling information and solving problems

how you extract information and rearrange it in a sensible pattern and how you carry out calculations and make predictions

• Select and organise information from graphs, • tables and written text

• Change information from one form to another, e.g. draw graphs

• Arrange data and carry out calculations

• Identify patterns from information given and draw conclusions

• Explain scientifi c relationships, e.g. use the moving (kinetic) particle theory to explain ideas about solids, liquids and gases

• Make predictions and develop scientifi c ideas • Solve problems

Section 3: What will be tested?

AO3

Experimental skills and investigations

planning and carrying out experiments, recording and analysing information

• Follow instructions to set up and use apparatus safely

• Make observations and measurements and record them with regard to precision, accuracy and units • Analyse experimental results

• Plan and carry out an experiment describing any problems and suggesting improvements

Section 4: What you need to know

Section 4: What you need to know

The following table describes the things you may be tested on in the examination.

The main headings in the topic areas are usually followed by the details of what you need to know.

How to use the table

You can use the table throughout your course to check the topic areas you have covered.

There is no need to start at the beginning. Use it when you fi nish a section of your course to make sure that you understand what you should be able to do.

When you think you have a good knowledge of a topic, you can tick the appropriate box in the checklist column.

Test yourself as follows:

• cover up the details with a piece of paper • try to remember the details

• when you have remembered the details correctly, put a tick in the appropriate box.

You can also use it as a revision aid at the end of the course to fi nd out any weaknesses or areas you need to do some work on or ask your teacher about.

If you use a pencil to tick the boxes, you can retest yourself whenever you want by simply rubbing out the ticks. If you are using the table to check which topics you have covered, you can put a tick in the topic column, next to the appropriate bullet point.

The column headed ‘Comments’ can be used:

• to add further information about the details for each bullet point

• to add learning aids, e.g. simple equations set out in a triangle to help in rearranging the equation • to show areas of diffi culty/things you need to ask your teacher about.

There are six major themes in the table: General Physics

Newtonian Mechanics Energy and Thermal Physics Waves

Electricity and Magnetism Atomic Physics.

Each theme contains a number of sections. The 27 sections cover the whole syllabus. Each section contains a number of topics and the table lists what you should be able to do in each topic.

Section 4: What you need to know

You should note that questions on Section 25, Electronic Systems, only appear in Paper 2 and are always set as an alternative within a question.

Your teacher may have chosen not to cover this section in your course. In that case you should not need to learn that topic.

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts T H E M E 1 G e n e ra l Ph y s ic s 1 . Ph y s ic a l q u a n ti ti e s , u n it s a n d m e a s u re m e n ts S c alars and v e c tors • defi ne the t e rm s sc alar and ve c to r • fi nd the r e s u lt an t o f t w o v e c tors by a graph ic a l me tho d • k n o w w h ich o f the f o llo w ing ar e sc alars and w h ich ar e v e c tors : dist ance , displacemen t, leng th, sp eed , v e lo cit y, time , ac

celeration, mass and f

o rc e

† † †

M e as ur emen t te ch n iques • describ e ho w t o me as ur e dif fer en t leng ths w ith s u it able ac curac y using t a p e s, rules, micr ome ters, and c a lip e rs (the use o f a v e rn ier sc ale is no t re q u ir e d ) • describ e ho w t o me as ur e dif fer en t time in te rv als using clo c ks and st o p wat c hes

†

†

Un its and sy mb ols • re c o gn

ise and use the S

I syst em o f un its – y o ur t e acher w ill ha v e mor e in fo rm ation

†

THE M E 2 N ew tonian M e c h ani c s 2 . K inem a tic s S p eed , v e lo cit y and accelera tion • st at e w h at is me an t by sp ee d • st at e w h at is me an t by v e lo cit y • c a lculat e a v erage sp ee d using a v er ag e s p eed = di s tan ce t ra v el le d / ti m e ta k e n • st at e w h at is me an t by un if or m ac celeration • c a lculat e ac celeration using ac c e ler a ti on = c h ang e in v eloc ity / ti m e ta k e n • e x plain w h at is me an t by non -un if or m ac celeration

† † †

† †

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts G ra p hic a l an al ysis o f mo tion • plo

t and use dist

ance -t ime graphs. • plo t and use sp ee d -time graphs. • re c o gn

ise the shap

e o f a sp ee d -time graph f o r a b o d y : at r est , mo v ing w ith un if or m sp ee d mo v ing w ith un if or m ac celeration mo v ing w ith non -un if or m ac celeration • c a lculat e the ar e a under a sp ee d -time graph t o fi nd the dist ance tra v el le d by a b o d y mo v ing w ith c o nst a n t sp ee d or c o n s ta n t accelera tion

† † †

†

F ree -f al l • st at e that the ac celeration o f fr ee -f al l f o r a b o d y ne ar t o the E a rt h is c o nst a n t • k n o w that it is ab out 1 0 m /s 2 • describ e in w o rd s the mo tion o f b o d ies fal ling w ithout air re s is ta n c e • describ e in w o rd s the mo tion o f b o d ies fal ling w ith air re s is ta n c e • e x plain ho w a b o d y r e aches t e rm inal v e lo cit y

†

† †

†

†

3. D y n a mi c s Ba la nced a n d u n ba la nced fo rc e s • st at e N e w ton ’s th ir d la w • describ e the e ff e c t o f b a lance d and unb a lance d f o rc es on a b o d y • describ e the wa ys in w h ich a f o rc e ma y change the mo tion o f a b o d y • d o c a

lculations using the e

q u a tion fo rc e = mass × ac c e ler a ti on

† †

†

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts F ric tion • e x plain the e ff e c ts o f fric tion on the mo tion o f a b o d y • describ e ho w the f o llo w ing af fe c t fric tion b e tw een the w h eels o f a v e h

icle and the r

o ad : ty re s u rf ace ro ad c o ndition s (i ncl u di ng s k id di ng) bra k ing f o rc e • describ e ho

w these change the

: bra k in g dist ance think ing dist anc e st o p ping dist ance o f a v e h icle

† †

†

Cir c ular mo tion • describ e in w o rd s ho w o b jec ts mo v e in a cir c ular p a th due t o a c o nst a n t f o rc e p e rp endicular t o the dir e c tion o f tra v el • ap pl y ide a s ab out cir c ular mo tion t o : elec tr ost a tic f o rc es on an elec tr on in an at om, gra v it ational f o rc es on a s a te llit e , the mo tion o f plane

ts in the solar syst

em

†

†

4 . M a s s , we ig h t a n d d e n s it y M a ss and w e igh t • st at e that mass is a me as ur e o f the amoun t o f s u bst a nce in a b o d y • st at e that mass o f a b o d y r e sists change fr om its st at e o f rest or mo tion • c a lculat e w e igh t fr om the e q u a tion we ig h t = mass × g ra v it a tional fi eld s tr e ng th • e x plain that w e igh ts, and ther e for e masses, ma y b e c o mp ar e d using a b a lance • describ e ho w t o me as ur e mass and w e igh t by using su it a b le b a la n c e s

†

†

†

†

†

Gra v it ational fi elds • st at e that a gra v it ational fi eld is a r e gion in w h ich a mass e x p e riences a f o rc e due t o gra v it ational at trac tion

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts D e nsit y • describ e ho w t o use a me as uring c y linder t o me as ur e the v o lu me o f a liquid or solid. • describ e ho w t o de te rm

ine the densit

y o f: a liquid a r e gularl y shap e d solid an ir re gularl y shap e d solid w h ich sin k s in wat e r (v ol ume by d is p la c e men t) • d o c a

lculations using the e

q u a tion den s it y = mass / vo lu m e

†

†

†

5. T u rn in g e ff e c t o f f o rc e s M o men ts • describ e the momen t o f a f o rc e in t e rm s o f its t u rn ing ef fe c t • describ e simple e v er y d a y e x amples o f momen ts • st at e the principle o f momen ts f o r a b o d y in e q ui libri u m • d o c a lculations using momen t o f a f o rc e = fo rc e × p e rp end icular d is tanc e f rom t h e p iv o t • d o c a

lculations using the principle o

f momen ts • describ e ho w t o v e rif y the principle o f momen ts

†

† † †

† †

C e n tr e o f mass • describ e ho w t o fi nd the p o sition o f the cen tr e o f mass o f a plane lamina

†

St abi lit y • describ e in w o rd s the e ff e c t o f the p o sition o f the cen tr e o f mass on the st abi lit y o f simple o b jec ts

†

6. De form ation E lastic de fo rm ation • st at e that a f o rc e ma y pr o d uce a change in si ze and shap e o f a b o d y • plo t and use e x te nsion -lo ad graphs f o r an elastic solid • describ e an e x p e rimen t t o me as ur e the e x te nsion pr o d uce d by dif fer en t lo ads f o r an elastic solid • k n o w w h at is me an t by the ‘ limit o f pr o p or tionalit y ’ f o r an elastic solid • c a lculat e e x te nsions f o

r an elastic solid using

e x te nsion is dir e c tl y pr o p or tional t o lo ad

†

† †

†

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 7. P re s s u re P ress u re • defi ne the t e rm pr ess u re in t e rm s o f f o rc e and ar e a • d o c a

lculations using the e

q u a tion pr e s s u re = fo rc e / ar ea • e x plain ho w pr ess u re varies w ith f o rc e and ar e a in a range o f e v er y d a y e x amples

† †

†

P ress u re changes • describ e ho w the heigh t o f a liquid c o lu mn ma y b e use d to me as ur e the atmospheric pr ess u re • e x plain in w o rd s ho w the pr ess u re b e ne ath a liquid s u rf ace changes w ith dep th and densit y o f the liquid in sim p le e v er yd ay e x am p les • d o c a

lculations using the e

q u a tion pr e s s u re = h ρ g • describ e ho w a manome te r is use d t o me as ur e pr ess u re dif fer enc e s • describ e and e x

plain the transmission o

f pr ess u re in h y dra u lic syst ems • describ e the w o rk ings o f: the h y dra u lic pr ess, h y dra u lic bra k es on v e h icles • describ e ho w changing the pr ess u re ap plie d t o a g a s at c o nst a n t t e mp erat ur e c a uses a change in v o lu me • d o c a lculations using p 1 V1 = p 2 V2

†

†

†

†

†

†

†

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts T H E M E 3 E n e rg y a n d T h e rm a l Ph y s ic s 8 . E n e rg y s o u rc e s a n d t ra n s fe r o f e n e rg y E n er g y f o rm s •

list the dif

fer en t f o rm s o f ener g y • giv e e x amples in w h ich e a ch f o rm o c curs • st at e the principle o f the c o nser vation o f ener g y • ap pl y th is principle t o the c o n v ersion o f ener g y fr om one fo rm t o ano ther • st at e that k ine tic ener g y Ek = ½ mv 2 • st at e that p o te n tial ener g y EP = mgh • d o c a

lculations using these e

q u a tions

† † † †

† † †

M a jor sour ces o f ener g y • list r e ne

wable and non

-r e ne wable ener g y sour ces • describ e the ener g y c o n v ersions t a k ing place w h en using the f o llo w ing ener g y sour ces : – chemic al /f uel ener g y ( re -gr ouping o f at oms ) – h y dr o e lec tric generation ( e

mphasising the mechan

ic al ener gies in v o lv e d ) – solar ener g y ( n uclei o f at

oms in the Sun

) – n u cle a r ener g y – g e o ther m al ener g y – w ind ener g y • e x plain ho w n u cle a r f u sion r e le ases ener g y • e x plain ho w n u cle a r fi ssion r e le ases ener g y • describ e the generation o f elec tricit y and dra w a blo c k diagram o f the pr o c ess fr om f u el input t o elec tricit y output • discuss the en v ir o nmen ta l iss u es asso ciat e d w ith p o w e r genera tion

† †

† †

† † † † † † †

†

W o rk • c a lculat e w o rk d o ne fr om the e q u a tion wo rk = fo rc e × d is tanc e mo v e d in d ir e c tion o f t h e f o rc e

†

Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts Ef fi cienc y • c a lculat e the e ffi c ienc y o f an ener g y c o n v ersion using the e q u a tion ef fi c iency = ener gy c o n v ert e d t o t h e r e quir ed f o rm to ta l ener gy inpu t • discuss the e ffi c ienc y o f ener g y c o n v ersions in c o mmon use , p a rt icularl y those giv ing elec tric al output •

discuss the use

fulness o f ener g y output fr om a n u mb er o f ener g y c o n v ersions

†

†

†

Po w e r • c a lculat e p o w e r fr om the e q u a tion po w e r = wo rk d o n e / ti m e ta k e n

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9 . T ra n s fer of th er m a l energ y C o nduc tion • describ e ho w t o distinguish b e tw een g o o d and b a d co n d uct o rs o f h e a t • describ e he at transf er in solids by the mo v e men t o f molecules • describ e he at transf er in solids by the mo v e men t o f fr ee elec tr ons

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C o n v ec tion • describ e c o n v ec tion in f u

ids using densit

y changes

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R a diation • describ e ho w he at is transf er re d by radiation • describ e ho w t o distinguish b e tw een g o o d and b a d emit te rs o f in fra -r e d radiation • describ e ho w t o distinguish b e tw een g o o d and b a d absor b ers o f in fra -r e d radiation

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T o ta l transf er • describ e ho w he at is transf er re d t o or fr om bui ldings and ro o m s • st at e the imp o rt an t me tho d s o f ther mal ins u lation o f bui ldi ngs • describ e ho w these imp o rt an t me tho d s ins u lat e the bui ldi ngs

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 1 0 . T e m p e ra tu re Pr in c ip le s o f ther mome tr y • e x plain ho w a ph ysic al pr o p er ty w h ich varies w ith te mp erat ur e ma y b e use d f o r the me as ur emen t o f te m p e ra tu re • st at e e x amples o f s u ch pr o p er ties • e x

plain the nee

d f o r fi xe d p o in ts • st at e w h at is me an t by the ice p o in t and st e a m p o in t • discuss the f e at ur es : sensitiv it y range line arit y o f ther mome te rs

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P rac tic a l ther mome te rs • describ e the struc tur e and ac tion o f liquid -i n -glass thermome te rs (i ncl u di ng cl in ic al) • describ e the struc tur e and ac tion o f a ther mo c o uple ther mome te r • e x

plain the use o

f a ther mo c o uple ther mome te r f o r me as uring h igh t e mp erat ur es and those w h ich var y rapidl y

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1 1 . T h e rm a l p ro p e rt ie s o f m a tt e r Spe c ifi c he at c a p a cit y • describ e a rise in t e mp erat ur e o f a b o d y as an incr e a se in it s in te rn al ener g y ( rand o m ther m a l ener g y ) • defi ne the t e rm s he at c a p a cit y • defi ne the t e rm sp eci fi c he at c a p a cit y • c a lculat e he at transf er re d using the e q u a tion th er mal ener gy = mass × speci fi c hea t c a p a c ity × c h ang e in t e mp er a tur e

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts M e lting and b o iling • d e scrib e melting /solidi fi c a tion and b o iling /c o nd ens a tion as a transf er o f ener g y w ithout a change in t e mp erat ur e • st at e the me an ing o f melting p o in t • st at e the me an ing o f b o iling p o in t • e x

plain the dif

fer ence b e tw een b o iling and e v ap oration • defi ne the t e rm lat e n t he at • defi ne the t e rm sp eci fi c lat e n t he at • e x plain lat e n t he at by w riting ab out molecules • c a lculat e he at transf er re d in a change o f st at e using the equa ti on th er mal ener gy = mass × speci fi c la te n t hea t

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T h er mal e x p a nsion o f

solids, liquids and g

a ses • describ e in w o rd s the ther mal e x p a nsion o f solids, liquids and g a ses • describ e the r e lativ e or der o f magn it ude o f the e x p a nsion o

f solids, liquids and g

a ses • list and e x plain some o f the e v er y d a y ap plic ations and c o nse q uences o f ther mal e x p a nsion • describ e in w o rd s ho w a change o f t e mp erat ur e af fe c ts the v o lu me o f a g a s at c o nst a n t pr ess u re

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1 2 . K in e ti c m o d e l o f m a tt e r St at es o f mat ter • st at e the pr o p er ties o

f solids, liquids and g

a ses

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M o lecular mo del • describ e in w o rd

s the molecular struc

tur e o f solids, liquids and g a ses • lin k the pr o p er ties o

f solids, liquids and g

a ses t o : the f o rc es b e tw

een the molecules

the dist ances b e tw een molecules the mo tion o f the molecules • describ e ho w changing the t e mp erat ur e af fe c ts the mo tion o f molecu les • e x plain the pr ess u re o f a g a s in t e rm s o f the mo tion o f its molecules

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts E v ap oration • describ e e v ap oration in t e rm s o f the esc a p e o f mor e ener ge tic molecules fr om the s u rf ace o f a liquid • describ e ho w e v ap oration is af fe c te d by : te m p e ra tu re su rf a c e a re a dra u gh t o v er the s u rf ace • e x plain that e v ap oration c a uses c o oling

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THEME 4 W a v e s 1 3 . G e n e ra l wav e p ro p e rt ie s D e scribing wa v e mo tion • describ e w h at is me an t by a wa v e mo tion • describ e the use o f: ro p e s spri ngs ripple t a n k s to demonstrat e wa v e mo tions

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Wa v e t e rm s • st at e w h at is me an t by a wa v e fr o n t • defi ne the t e rm s : speed fre q u e n c y wa v e le n g th ampli tude • d o c a lculations using v eloc ity = fr e q u e n c y × wa v e le n g th • describ e a trans v erse wa v e • describ e a longit u dinal wa v e • e x

plain the dif

fer ences b e tw een trans v erse and longit u di nal wa v e s

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts Wa v e b e ha v iour • describ e ho w a rip p le t a n k is use d t o sho w : – r e fl ec tion at a plane s u rf ace – re frac tion due t o a change o f sp ee d • describ e simple e x p e rimen ts t o sho w the r e fl ect ion o f sound wa v e s • describ e a simple e x p e rimen t t o sho w the r e frac tion o f sound wa v e

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1 4 . L ig h t Refl ec tion o f ligh t • defi ne the f o llo w ing t e rm s : nor m al ang le o f inc idenc e ang le o f r e fl ec ti on • describ e an e x p e rimen t t o i llu strat e the la w o f r e fl ect ion • describ e an e x p e rimen t t o fi nd the p o sition o f an image fo rm e d by a plane mir ror • describ e the pr o p er ties o f the image pr o d uce d by a plane mir ro r • k n o w

that the angle o

f incidence is e q u a l t o the angle o f re fl ect ion a n d • use th is in dra w

ing diagrams and c

a lculations

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Re frac tion o f ligh t • defi ne the f o llo w ing : ang le o f inc idenc e ang le o f r e fr ac ti on re fr a c ti v e i n d e x • describ e e x p e rimen ts t o sho w r e frac tion o f ligh t th ro ugh glass blo c k s • d o c a

lculations using the e

q u a tion sin i / sin r = n • defi ne the t e rm s : cr it ic a l a n gl e to ta l in te rn al r e fl ec ti on • d o c a

lculations using the e

q u a tion sin c = 1/ n • describ e e x p e rimen ts t o sho w t o ta l in te rn al r e fl ect ion • describ e ho w o p tic a l fi br es ar e use d in te lec o mmun ic ations and • st at e the ad van tages o f their use

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts T h in c o n v er ging and div e rg in g len s es • describ e the ac tion o f th in c o n v er ging lenses on a b e am of li g h t • describ e the ac tion o f th in div e rg ing lenses on a b e am o f lig h t • defi ne the t e rm f o c a l leng th • dra w ra y diagrams t o sho w the f o rm ation o f r e al and v ir tu a l images o f an o b jec t by a c o n v er ging lens • dra w ra y diagrams t o sho w the f o rm ation o f a v ir tu a l image by a div e rg ing lens • defi ne the t e rm line ar magn ifi ca ti o n • dra w sc ale diagrams t o de te rm ine the f o c a l leng th o f a c o n v er

ging lens nee

d e d f o r p a rt icular val u es o f magn ifi ca ti o n • describ e the use o f a single lens : as a magn if ying glass in a c a mera n a pr ojec to r in a pho tograph ic e n la rg e r • dra w ra y diagrams t o sho w ho w the image is f o rm e d by a magn if ying glass : in a c a mera in a pr ojec to r in a pho tograph ic e n la rg e r • dra w ra y diagrams t o sho w the f o rm ation o f images in the nor m al e y e : a shor t-sigh te d e y e a long -sigh te d e y e • describ e the c o rr ec tion o f shor t-sigh t • describ e the c o rr ec tion o f long -sigh t

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1 5 . Ele c trom a g ne tic s p e c trum D isp ersion o f ligh t • describ e the disp ersion o f ligh t by a glass prism. • st at e the c o lours o f the sp ec trum • e x plain ho w the c o lours ar e r e lat e d t o fr e q uenc y and wa v e leng th

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts Pr ope rt ie s o f elec tr omagne tic wa v e s • st at e that al l elec tr omagne tic wa v e s tra v el w ith the s a me h igh sp ee d in air • k n o w that the sp ee d is 3 × 1 0 8 m/ s • list the c o mp onen ts o f the elec tr omagne tic sp ec trum • describ e the imp o rt an t f e at ur es o f e a ch c o mp onen t o f the elec tr omagne tic sp ec trum

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Ap p lic a ti o n s o f elec tr omagne tic wa v e s • discuss ho w e a ch c o mp onen t is use d : – radio w a v es in radio and t e le v ision c o mmun ic ations – micr o w a v es in s a te llit e t e le v ision and in t e lephones – in fra -r e d in household elec tric al ap pliances : in te le v ision c o n tr o llers in in tr ud er al ar ms – ligh t in o p tic a l fi br es : in me dic a l uses in te lephone c a bles – ultra -v iole t in s u nb e d s i n fl uor escen t t u b e s i n s te ri lis a ti o n – X -ra ys in hospit als f o r me dic a l imaging in hospit als f o r k ill ing c a ncer ous cel ls in engineering f o r de te c ting cracks in me ta l o b jec ts – g a mma ra ys in hospit als f o r k ill ing c a ncer ous cel ls, in engineering f o r de te c ting cracks in me ta l o b jec ts

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 1 6 . Soun d S o und wa v e s • describ e the pr o d uc tion o f sound by v ibrating sour ces • e x plain w h y sound wa v e s ar e longit u dinal • e x plain w h at is me an t by compr e s s ion s and ra re fa c ti o n s • st at e the ap pr o x imat e range o f a u dible fr e q uencies • e x plain sound wa v e s nee d a me di um, and • describ e an e x p e rimen t t o demonstrat e th is • e x plain ho w the loudness o f a sound wa v e dep e nds on its amplitud e • e x plain ho w the pit c h o f sound wa v e s dep e nds on its fr e q uenc y • describ e ho w the r e fl ec tion o f sound ma y pr o d uce an echo • e x plain w h at is me an t by the quali ty (timbr e ) o f a sound wa v e • describ e w h at af fe c ts the qu alit y (timbr e ) o f sound wa v e s, and • describ e ho w these c a n b e sho w n on a c a tho d e ra y osci llosc o p e ( c .r .o .)

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S p ee d o f sound • describ e a simple me tho d o f me as uring the sp ee d o f sound in air , and • e x plain ho w the sp ee d is c a lculat e d fr om the me as ur emen ts • st at e ap pr o x imat e magn it ude o f the sp ee ds o f sound in air in liquid s in so lid s

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Ultrasound • defi ne ul tr asound • describ e the uses o f ultrasound : in c le a nin g in d e te c tin g fl a w s ( q u a lit y c o n tr o l) in pr e -nat a l sc an n ing

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts T H E M E 5 E le c tr ic it y a n d M a g n e ti s m 1 7 . M a g n e ti s m a n d e le c tr o m a g n e ti s m L a ws o f magne tism • k n o w that magne ts ha v e N ( n or th ) and S ( s outh ) p o les • st at e that unli k e p o les at trac t and li k e p o les r e p e l

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M a gne tic pr o p er ties o f ma tt e r • st at e the dif fer ences b e tw een magne tic , non -magne tic a n d magn e ti s ed ma te ria ls • describ e an elec tric al me tho d o f magne tis ation • describ e an elec tric al me tho d o f demagne tis ation • e x plain w h at is me an t by a p e rm anen t magne t • k n o w that st eel b e ha v e s as a p e rm anen t magne t • describ e uses o f p e rm anen t magne ts • e x plain w h at is me an t by a t e mp orar y magne t • k n o w that ir on b e ha v e s as a t e mp orar y magne t • describ e uses o f t e mp orar y magne ts • e x plain w h at is me an t by induce d magne tism • describ e ho w t o plo t magne tic fi eld lines w ith a plo tting com p a s s • e x plain w h at is me an t by magne tic scr e en ing • e x

plain the choice o

f mat e rial f o r magne tic scr e en ing • describ e the use o f magne tic mat e rials in a c o mput er har d dis k driv e

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E lec tr omagne tism • describ e the p a tt er n o f the magne tic fi eld due t o : c u rr e n ts i n s tra ig h t wi re s cur ren ts in solenoids • st at e the e ff e c t on the magne tic fi eld o f changing : the magn it ude o f the cur ren t the dir e c tion o f the cur ren t • describ e uses o f elec tr omagne ts in : re la y s ci rc u it -br ea k e rs loudsp ea k e rs

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 1 8 . Static ele c tric it y L a ws o f elec tr ost a tic s • k n o w that ther e ar e p o sitiv e and neg a tiv e char ges • st at e that unli k e char ges at trac t and li k e char ges r e p e l

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Pr in c ip le s o f elec tr ost a tic s • describ e e x p e rimen ts t o sho w elec tr ost a tic char ging by fr ic tion • e x

plain that char

ging o f solids in v o lv es a mo v e men t o f elec tr ons • k n o w that char ge is me as ur e d in c o ulombs • describ e an elec tric fi eld as a r e gion in w h ich an elec tric char ge e x p e riences a f o rc e • st at e the dir e c tion o f lines o f f o rc e ( e lec tric fi eld lines ) • describ e simple elec tric fi eld p a tt er ns • describ e the sep a ration o f char ges by induc tion • e x

plain the dif

fer ences b e tw een elec tric al c o nduc to rs and ins u lat o rs • giv e e x amples o f elec tric al c o nduc to rs • giv e e x amples o f elec tric al ins u lat o rs • e x plain w h at is me an t by ‘ e ar th ing ’ a char ge d o b jec t

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Ap p lic a ti o n s o f elec tr ost a tic s • describ e e x amples w h er e char ging c o uld b e a pr o b lem, e.g . li g h tn in g • describ e e x amples w h er e char ging is help fu l, e .g. pho to c o p ier , elec tr ost a tic pr ecipit at or

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1 9 . C u rr e n t e le c tr ic it y Cur ren t • st at e that a cur ren t is a fl o w o f char ge • k n o w that cur ren t is me as ur e d in amp e re s • d o c a

lculations using the e

q u a tion ch a rge = cur ren t × ti m e • describ e the use o f an amme te r w ith dif fer en t ranges

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts E lec tr omo tiv e f o rc e (e. m .f .) • e x plain that e .m. f. is the ener g y c o n v er te d by a p o w e r s u p p ly ( e .g . cel l) in mo v ing a un it char ge ar ound a cir c uit • st at e that e .m. f. is w o rk d o ne /c har g e • c a lculat e the t o ta l e .m. f. w h en se v e ral p o w e r s u p p lies ar e ar range d in series, and • describ e ho w th is is use d in the design o f b a tt eries • e x plain the ad van tage o f ma k ing a b a tt er y fr om se v e ral p o w e r s u p p lies ar range d in p a ral lel

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Po te n tial dif fer ence ( p .d .) • k n o w that p .d. is me as ur e d in v o lts • e x

plain that the p

.d. is me as ur e d acr o ss a cir c uit com p o n e n t • e x

plain that the p

.d. acr o ss a c o mp onen t is the w o rk d o ne w h en a un it char ge p a sses th ro ugh the c o mp onen t • st at e that the v o lt is giv e n by J /C • describ e the use o f a v o ltme te r w ith dif fer en t ranges

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts Resist ance • k n o w that re s is ta n c e = p.d . / cur ren t • d o c a

lculations using the e

q u a tion re s is ta n c e = vo lta g e / cur ren t • describ e an e x p e rimen t t o me as ur e the r e sist ance o f a me ta llic c o nduc to r using a v o ltme te r and an amme te r • st at e O h m ’s L a w • e x plain that O h m ’s L a w is onl y o b e y e d by a r e sist or at co n s ta n t t e m p e ra tu re • d o c a lculations w ith the r e lationsh ips f o r a w ir e : re sis tanc e is d ir e c tl y p ro p ort ional t o leng th re sis tanc e is in v e rs el y p ro p ort ional t o c ross -sec tional ar ea • c a lculat e the t o ta l r e sist ance o f se v e ral r e sist ors : in ser ies in p a ra llel • s k e tch cur ren t/ v o lt age graphs f o r: re s is to r fi la men t la mp • describ e the e ff e c t o f t e mp erat ur e incr e a se on the re s is ta n c e of : a r e sist or a fi la men t la mp • describ e ho w the r e sist ance o f a ligh t-dep e nden t r e sist or varies w ith the in te nsit y o f ligh t

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 2 0 . D .C . c ir c u it s Cur ren t and p o te n tial dif fer enc e in c ir c uit s • k n o w the cir c uit sy mb ols f o r: p o w e r sour ces ( c el l, b a tt er y or a. c . mains ) s w it ches ( c lose d and o p en ) esist o rs ( fi x e d and variable ) ligh t dep e nden t r e sist ors ther mist ors. la mps amme te rs vo lt m e te rs magne tising c o ils be lls fuses rela y s lig h t-emit tin g d io d es re c tif ying dio d es. • dra w cir c uits c o n tain ing these c o mp onen ts

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S e ries and p a ral lel ci rc u its • st at

e that the cur

ren t at e v er y p o in t in a series cir c uit is the s a me • st at e that the s u m o f the p .d.s in a series cir c uit is e q u a l to the p .d. acr o ss the w h ole cir c uit • st at

e that the cur

ren t fr om the sour ce is the s u m o f the cur ren ts in the sep a rat e branches o f a p a ral lel cir c uit • d o c a lculations on the w h ole cir c uit , r e c a

lling and using

fo rm ul ae in c lu d in g R = V / I and these f o r p o te n tial dif fer ences in series, r e sist

ors in series and r

e sist ors in pa ra lle l

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 2 1 . P ra c ti c a l e le c tr ic it y Uses o f elec tricit y • describ e the use o f elec tricit y in : he ating lig h tin g mo to rs • d o c a

lculations using the e

q u a tions po w e r = vo lta g e × cur ren t ener gy = vo lta g e × cur ren t × ti m e • c a lculat e the c o st o f using elec tric al ap pliances w h er e the ener g y un it is the k W h

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D a ngers o f elec tricit y • st at e the haz a rd s o f: da m a g e d i n s u la ti o n ove rh e at in g of c a b le s da m p co n d it io n s

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S a fe use o f elec tricit y in the home • describ e the use o f: fuses circ u it br ea k e rs • e x plain w h at is me an t by : fuse r a tin g s cir c uit br e a k e r se tt ings • e x

plain the nee

d f o r: e a rt h ing me ta l c a ses do ubl e i n s u la ti on • st at e the me an ing o f the t e rm s : liv e neu tr a l eart h • describ e ho w t o w ir e a mains pl ug • e x plain w h y s w it ches, f u

ses and cir

c uit br e a k e rs ar e alwa ys place d in the liv e c o nduc to r

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 22 . Ele c trom a g ne tism F o rc e on a cur ren t-ca rr y in g c o n d u c to r • describ e e x p e rimen ts t o sho w the f o rc e on : a cur ren t-c a rr ying c o nduc to r in a magne tic fi eld a b e am o f char ge d p a rt icles in a magne tic fi eld • describ e the e ff e c t on the f o rc e o f: re v e

rsing the cur

ren

t

re

v

e

rsing the dir

e c tion o f the fi eld • st at e the r e lativ e dir e c tions o f f o rc e , fi

eld and cur

ren t: (u se o f Fleming ’s le ft hand rule ) • describ e the magne tic fi eld p a tt er ns b e tw een cur ren ts in pa ra lle l co n d u c to rs •

use the magne

tic fi eld p a tt er ns t o fi nd the dir e c tion o f the f o rc es on the w ir e s

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T h e d. c . mo to r • e x plain ho w a cur ren t-c a rr ying c o il in a magne tic fi eld e x p e riences a t u rn ing e ff e c t • describ e the e ff e c t o f: incr e a sing the n u mb er o f t u rn s on the c o il incr e a

sing the cur

ren t • describ e ho w th is t u rn ing e ff e c t is use d in an elec tric mo to r • e x plain w h y a split-ring c o mmut at or is use d in a simple mo to r • describ e the e ff e c t o f w inding the c o il on to a so ft -i ro n cyl in d e r

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2 3 . E le c tr o m a g n e ti c i n d u c ti o n Pr in c ip le s o f elec tr om agne tic in du c tio n • describ e an e x p e rimen t w h ich sho w s that a changing magn e ti c fi eld c a n induce an e .m. f. in a cir c uit • st at e the fac tors af fe c

ting the magn

it ude o f the induce d e.m .f . • k n o w

that the dir

e c tion o f a cur ren t pr o d uce d by an induce d e .m. f. o p p o

ses the change pr

o d ucing it ( L en z’ s La w ) • describ e a simple demonstration o f Len z’ s L a w

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts T h e a. c . generat o r • describ e a simple f o rm o f a. c . generat o r ( ro tating c o il or rot a ti n g m a g n et ) • e x

plain the pur

p ose o f slip rings (w her e nee d e d ) • s k e tch a graph o f v o lt age output ag ainst time f o r a simple a. c . generat o r

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T h e transf or mer • describ e the struc tur e o f a simple ir on -c or e d transf or mer • describ e the o p eration o f a simple ir on -c or e d transf or mer • st at e the ad van tages o f h igh v o lt age transmission • c o mp ar e under g ro und p o w e r transmission w ith o v erhe ad lines in t e rm s o f: en v ir o nmen ta l imp a c t co s t

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24. Introduc to ry e le c tronic s T h er mion ic emission • st at e that elec tr ons ar e emit te d by a ho t me ta l fi la men t • e x plain that t o al lo w the elec tr ons t o fl o w r e quir es b o th : h ig h po s it iv e po te n ti a l v e ry lo w g a s pr ess u re • describ e the defl ec tion o f an elec tr on b e am by : elec tric fi elds magn e ti c fi elds • st at e that the fl o w o f elec tr ons ( e lec tr o n cur ren t) is fr om ne g a ti v e t o p o siti v e • k n o w that the fl o w o f elec tr ons is in the o p p o sit e dir e c tion t o c o n v en tional cur ren t

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Simple tr e a tmen t o f c a tho d e -ra y osci llosc o p e (c .r .o.) • describ e in outline the b a sic struc tur e o f a c .r .o . • describ e in outline the ac tion o f a c .r .o . • describ e the use o f a c .r .o .: to displa y wa v e fo rm s to me as ur e p .d.s. to me as ur e shor t in te rv als o f time

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts A c

tion and use o

f cir c uit com p o n e n ts • describ e the r e sist or c o lour c o de • e x plain ho w the r e sist or c o lour c o de c a n e a si ly b e use d to lab e l v e ry lar g e and v e ry smal l r e sist ances • e x plain w h y w idel y dif fer en t val u es o f r e sist ance ar e nee d e d in dif fer en t t y p e s o f cir c uit • e x plain w h y w e nee d t o use r e sist ors w ith v e ry dif fer en t p o w e r ratings • describ e the ac tion o f a ther mist or • e x

plain the use o

f a ther mist or as an input sensor • describ e the ac tion o f a ligh t-dep e nden t r e sist or • e x

plain the use o

f a ligh t-dep e nden t r e sist or as an input sensor • describ e the ac tion o f a variable p o te n tial div ider (p o ten tiome ter) • describ e the ac tion o f a dio d e in p a ssing cur ren t in one di re c tion on ly • describ e the ac tion o f a ligh t-emit ting dio d e in p a ssing cur ren t in one dir e c tion onl y and emit ting ligh t • describ e the ac tion o f a c a p a cit o r as a char ge st or e • e x plain ho w a c a p a cit o r is use d in time dela y cir c uits • describ e the ac tion o f a r e la y • e x plain ho w r e la ys ar e use d in s w it ch ing cir c uits • describ e cir c uits o p erating as : ligh t-sensitiv e sw it ches te mp eratur e o p erat e d alar ms (u sing a r e la y or o ther cir c uits )

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Section 4: What you need to know

Section 4: What you need to know

T opi c Y ou shoul d b e ab le t o : C he c k li s t C o mme n ts 2 5 . E le c tr o n ic sy s te m s ( N o te t h is to p ic i s o p ti o n a l. Q u e s ti o n s a re a lwa y s s e t a s a lt e rn a ti v e s .) S w it ch ing and lo gic ci rc u its • describ e the ac tion o f an npn transist or as an elec tric al ly ope ra ted s w it ch • e x

plain the use o

f an npn transist or in s w it ch ing cir c uits. • st at e in w o rd s and in truth t a ble f o rm , the ac tion o f the fo llo w ing lo gic g a te s : AN D OR NAN D NO R N O T (in v er te r) . • st at e the sy mb ols f o r the lo gic g a te s list e d ab o v e

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Bist

able and ast

a ble ci rc u its • describ e the use o f a bist able cir c uit • k n o w that bist able cir c uits e x h ibit the pr o p er ty o f memor y • describ e the use o f an ast a ble cir c uit ( p ulse generat o r) • describ e ho w the fr e q uenc y o f an ast a ble cir c uit is re lat e d t o the val u es o f the r e sistiv e and c a p a cit a tiv e com p o n e n ts

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T H E M E 6 A to m ic Ph y s ic s 2 6 . R a d ioa c ti v it y D e te c tion o f radio a c tiv it y • describ e the de te c tion o f: alp h a -p a rt ic les be ta -p a rt icl e s ga m m a -r a y s

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Charac te ristic s o f the th re e t y p e s o f emission • e x plain w h at is me an t by ra d io a c ti v e dec a y • fo r e a ch radio a c tiv e emission, st at e : the natur e their r e lativ e ion ising e ff e c t their r e lativ e p e ne trating p o w e r • st at e and e x

plain the rand

om emission o f radio a c tiv it y in dir e c

tion and time

• describ e the defl ec tion o f radio a c tiv e emissions in : elec tric fi elds magn e ti c fi elds

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