abc Standardisation Mark Scheme Additional Science 4463 / Physics 4451 PHY2H Unit Physics 2 General Certificate of Secondary Education

Transcription

1 Version : :4 27/06/08 abc General Certificate of Secondary Education Additional Science 4463 / Physics 445 Unit Physics 2 Standardisation Mark Scheme 2008 examination June series

2 Mark schemes are prepared by the Principal Examiner and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation meeting attended by all examiners and is the scheme which was used by them in this examination. The standardisation meeting ensures that the mark scheme covers the candidates responses to questions and that every examiner understands and applies it in the same crect way. As preparation f the standardisation meeting each examiner analyses a number of candidates scripts: alternative answers not already covered by the mark scheme are discussed at the meeting and legislated f. If, after this meeting, examiners encounter unusual answers which have not been discussed at the meeting they are required to refer these to the Principal Examiner. It must be stressed that a mark scheme is a wking document, in many cases further developed and expanded on the basis of candidates reactions to a particular paper. Assumptions about future mark schemes on the basis of one year s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper. Further copies of this Mark Scheme are available to download from the AQA Website: Copyright AQA and its licenss. All rights reserved. COPYRIGHT AQA retains the copyright on all its publications. However, registered centres f AQA are permitted to copy material from this booklet f their own internal use, with the following imptant exception: AQA cannot give permission to centres to photocopy any material that is acknowledged to a third party even f internal use within the centre. Set and published by the Assessment and Qualifications Alliance. The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee registered in England and Wales (company number ) and a registered charity (registered charity number ). Registered address: AQA, Devas Street, Manchester M5 6EX Dr Michael Cresswell Direct General

3 Question answers extra infmation mark (a)(i) 4 (V) allow mark f crect substitution 2 (ii) 5 (V) (9 their (a)(i)) crectly calculated e.c.f do not allow a negative answer (b)(i) thermist c.a.o (ii) 0 C to 20 C total 5 3

4 Question 2 (a)(i) protons neutrons answers extra infmation mark answers may be in either der (ii) 86 (iii) two fewer protons and two fewer neutrons do not accept two fewer protons and neutrons 84 protons 34 neutrons do not accept 28 protons and neutrons 2 (b)(i) 0.4 accept 5 / accept 40 % f 2 marks 2 allow mark f crect totalling =.8 allow mark f a clearly crect method with a clearly increct total (ii) any one from: nuclear weapon testing nuclear power (stations) do not accept nuclear accept nuclear/ radioactive waste nuclear accidents medical accept X-rays (c)(i) 2 accept 2: accept twice as big igne units Question 2 continues on the next page 4

5 Question 2 continued (ii) answers extra infmation mark No with a reasonable reason explained only going f two weeks so even staying f a year total exposure well under lowest limit f causing cancer Yes with a reasonable reason explained all levels of radiation are (potentially) hazardous () harm caused by lower doses may not have been recded () evidence may not be complete insufficient research into effect of small doses mark is f a time frame mark is f crectly relating to a dose accept low doses could still cause cancer accept all levels affect you do not accept radiation dose is high(er) do not accept level of background radiation is higher in Germany total 0 5

6 Question 3 (a)(i) answers extra infmation mark as one goes up so does the other (directly) proptional accept change by the same ratio (ii) steeper straight line through the igin judge by eye (iii) (b)(i) Yes with reason eg data would have been checked / repeated No with reason eg does not apply to all conditions / cars / drivers are only average values Maybe with a suitable reason eg cannot tell due to insufficient infmation stopping distance = thinking distance + braking distance accept produced by a reliable/ official/ government source do not accept it needs to be reliable 6

7 (ii) any two from: smooth road / loose surface facts must be to do with increasing braking distance 2 rain / snow / ice accept wet road/ petrol spills do not accept condition of road unless suitably qualified badly maintained brakes accept wn brakes accept bad/ wn/ rusty brakes do not accept old brakes wn tyres downhill slope/gradient accept bald tyres accept lack of grip on tyres do not accept old tyres heavily loaded car total 6 7

8 Question 4 (a) alternates between positive and negative answers extra infmation mark accept switches accept (constantly) changes accept goes up and down (b) potential difference between the neutral and earth (terminal) potential of the neutral terminal with respect to earth accept voltage f p.d (c)(i) (s) (ii) 40 (Hz) accept their (a)(i) total 5 8

9 Question 5 (a) 4 m/s 2 answers extra infmation mark allow mark f extracting crect infmation 2 igne negative sign 2 (b) 9 (s) total 4 9

10 Question 6 (a)(i) answers extra infmation mark droplets will repel each other accept droplets will spread out even coating of glue/ sand (on the paper) (ii) sand (becomes) positively charged accept attract positively charged sand repelled away from positive / lower plate allow attracted to the (negatively) charged glue/ paper opposite charges attract does not sce unless qualified (b) coulombs allow mark f crect transfmation and substitution accept C do not accept c accept 2mC 2 milli coulombs f 3 marks 2 total 7 0

11 Question 7 answers extra infmation mark (a) 4 (m/s) mark f crect transfmation of either equation mark f crect substitution with without transfmation mark f crect use of 0.6N max sce of 2 if answer is increct 3 (b) (c) greater change in momentum greater mass of air (each second) increase in velocity of air fce upwards increased fce up greater than fce down increase the time to stop decrease rate of change in momentum same momentum change reducing the fce on the toy accept speed f velocity lift fce is increased do not accept upthrust accept weight f fce down accept reduced deceleration/ acceleration do not accept answers in terms of the impact/ fce being absbed do not accept answers in terms of energy transfer do not credit impact is reduced total 8