9702 s05 ms_all

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS

GCE Advanced Subsidiary/Advanced Level

MARK SCHEME for the June 2005 question paper

9702 Physics

9702/01 Paper 1 (Multiple Choice), maximum raw mark 40

Mark schemes must be read in conjunction with the question papers and the Report on the

Examination.

• CIE will not enter into discussion or correspondence in connection with these mark schemes.

CIE is publishing the mark schemes for the June 2005 question papers for most IGCSE and GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses’.

Grade thresholds for Syllabus 9702 (Physics) in the June 2005 examination.

minimum mark required for grade: maximum mark

available A B E

Component 1 40 31 28 20

The thresholds (minimum marks) for Grades C and D are normally set by dividing the mark range between the B and the E thresholds into three. For example, if the difference between the B and the E threshold is 24 marks, the C threshold is set 8 marks below the B threshold and the D threshold is set another 8 marks down. If dividing the interval by three results in a fraction of a mark, then the threshold is normally rounded down.

June 2005

GCE AS/A LEVEL

MARK SCHEME

MAXIMUM MARK: 40

SYLLABUS/COMPONENT: 9702/01

PHYSICS Paper 1

(Multiple Choice)

Page 1 Mark Scheme Syllabus Paper

GCE AS/A LEVEL – JUNE 2005 9702 1

© University of Cambridge International Examinations 2005

Question Number

Key Question Number

Key

1 C 21 D

2 C 22 D

3 B 23 A

4 C 24 B

5 A 25 B

6 D 26 B

7 B 27 C

8 D 28 B

9 A 29 B

10 A 30 D

11 A 31 C

12 C 32 C

13 A 33 D

14 D 34 D

15 B 35 B

16 C 36 D

17 B 37 B

18 A 38 C

19 C 39 B

20 A 40 C


GCE Advanced Subsidiary and Advanced Level


9702 PHYSICS

9702/02 Paper 2 (Structured), maximum raw mark 60

This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. This shows the basis on which Examiners were initially instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. Any substantial changes to the mark scheme that arose from these discussions will be recorded in the published Report on the Examination. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the Report on the Examination.

• CIE will not enter into discussion or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the June 2005 question papers for most IGCSE and GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.



available A B E

Component 2 60 43 39 26


June 2005

GCE A AND AS LEVEL

MARK SCHEME

MAXIMUM MARK: 60


PHYSICS Paper 2 (Structured)


A and AS LEVEL – June 2005 9702 2


1 (a) allow 100 m s-1 → 900 m s-1 B1 [1]

(b) allow 0.5 kg m-3 → 1.5 kg m-3 B1 [1]

(c) allow 5 g → 50 g B1 [1]

(d) allow 2 × 103 cm3 → 9 × 103 cm3 B1 [1] 2 (a) speck of light B1

that moves haphazardly/randomly/jerkily/etc. B1 [2]

(b) randomness of collisions would be ‘averaged out’ B1 so less (haphazard) movement B1 [2]

(do not allow ‘more massive so less movement’)

3 (a) (i) ∆Ep = mg∆h C1

= 0.602 × 9.8 × 0.086 = 0.51 J A1 [2]

(do not allow g = 10, m = 0.600 or answer 0.50 J)

(ii) v2 = (2gh =) 2 × 9.8 × 0.086 or (2 x 0.51)/0.602 M1 v = 1.3 (m s-1) A0 [1]

(b) 2 × V = 602 × 1.3 (allow 600) C1 V = 390 m s-1 A1 [2]

(c) (i) Ek = ½mv2 C1

= ½ × 0.002 × 3902 = 152 J or 153 J or 150 J A1 [2]

(ii) Ek not the same/changes

or Ek before impact>Ek after/Ep after M1 so must be inelastic collision A1 [2] (allow 1 mark for ‘bullet embeds itself in block’ etc.)

4 (a) brittle B1 [1]

(b) (i) stress = force/area C1

= 60/(7.9 × 10-7)

= 7.6 × 107 Pa A1 [2] (ii) Young modulus = stress/strain C1

limiting strain = 0.03/24 (= 1.25 × 10-3) C1

Young modulus = (7.6 × 107)/(1.25 × 10-3) = 6.1 × 1010 Pa A1 [3]

(iii) energy = ½ × 60 × 3.0 × 10-4 C1

= 9.0 × 10-3 J A1 [2] (c) If hard, ball does not deform (much) B1

and either (all) kinetic energy converted to strain energy B1 If soft, Ek becomes strain energy of ball and window B1 (no mention of strain energy, max 2 marks)

or impulse for hard ball takes place over shorter time (B1) larger force/greater stress (B1) [3]




5 (a) When a wave (front) is incident on an edge or an obstacle/slit/gap M1 Wave ‘bends’ into the geometrical shadow/changes direction/spreads A1 [2]

(b) (i) d = 1/(750 × 103) C1

= 1.33 × 10-6 m A1 [2]

(ii) 1.33 × 10-6 × sin90° = n × 590 × 10-9 C1 n = 2 (must be an integer) A1 [2]

(iii) formula assumes no path difference of light before

entering grating or there is a path difference before the grating B1 [1]

(c) e.g. lines further apart in second order

lines fainter in second order (allow any sensible difference: 1 each, max 2) B2 [2] (if differences stated but without reference to the orders, max 1 mark)

6 (a) (i) lines normal to plate and equal spacing (at least 4 lines) B1

direction from (+) to earthed plate B1 [2] (ii) E = 160/0.08 M1

= 2.0 × 103 V m-1 A0 [1] (b) (i) correct directions with line of action of arrows

passing through charges B1 [1] (ii) force = Eq C1

= 2.0 × 103 × 1.2 × 10-15

= 2.4 × 10-12 N A1 [2]

(iii) couple = force × perpendicular separation M1

= 2.4 × 10-12 × 2.5 × 10-3 × sin35°

= 3.4(4) × 10-15 N m A1 [2] (iv) either rotates to align with the field

or oscillates (about a position) M1 with the positive charge nearer to the earthed plate/clockwise A1 [2]

7 (a) potential difference/current B1 [1]

(b) (i) 1) 1.13 W

2) 1.50 V B1 [1] (ii) power = V2 / R or power = VI and V = IR C1

R = 1.502/1.13

= 1.99 Ω A1 [2]




(iii) either E = IR + Ir or voltage divided between R and r C1

I = 1.5 / 2.0 (=0.75 A) p.d. across R = p.d. Across r = 1.5 C1 3.0 = 1.5 + 0.75r

r = 2.0 Ω so R = r = 1.99 Ω A1 [3]

(c) larger p.d. across R means smaller p.d. across r M1 smaller power dissipation at larger value of V A1 since power is VI and I is same for R and r A1 [3]

8 (a) position shown as A = 227, Z = 91 B1 [1]

(b) Pu shown as A = 243, Z = 94 B1

D shown with A = APu and with Z = (ZPu + 1) B1 [2]




9702 PHYSICS

9702/03 Paper 3 (Practical Test), maximum raw mark 25

This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. This shows the basis on which Examiners were initially instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. Any substantial changes to the mark scheme that arose from these discussions will be recorded in the published Report on the Examination. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the Report on the Examination.




available A B E

Component 3 25 22 20 15


June 2005

GCE A AND AS LEVEL

MARK SCHEME

MAXIMUM MARK: 25


PHYSICS Paper 3 (Practical Test)


A and AS LEVEL - JUNE 2005 9702 3


(a) (iii) Absolute uncertainty = 10 - 50, one mark. Can be credited from (a) (ii). [2]

Percentage uncertainty in first value of θ (i.e. ratio correct and x 100), one mark.

A bald answer with no working scores zero. Check value if absolute uncertainty given but no ratio. Allow half range/av. value x 100.

(b) Two difficulties: one mark each [2]

Examples of creditworthy answers are as follows:

Indicator on the newton-meter sticks Difficultly of too much compressive force to body of newton-meter

when clamping Difficult to position centre of protractor on knot Protractor ‘wobbles’ when being held by hand/‘wobbly hands’ Parallax error when reading the scale on the protractor/newton-meter Hard to align newton-meter parallel to line of action of F Difficulty of ensuring AB is horizontal Difficulty with zero on scale of newton-meter Thick string makes measurement of angle hard The centre of the knot could not be accurately located ‘The air-conditioning makes the string move’/reason for moving string

Candidate’s answers must relate to this experiment, and the measurement of F and θ .

Examples of vague answers which are not acceptable are as follows:

‘The string was moving’ or ‘the mass was oscillating’ ‘I did not have any difficulties’ ‘The clamp is loose, so I tightened it’ It was difficult to read the scale on the newton-meter/angle Unqualified ‘adjusting the retort stand’ The mass is not in equilibrium Unqualified ‘parallax error’

(c) Readings [5] 6 sets of readings scores three marks; 5 sets, two marks; 4 sets, one mark.

Check a value for 1/sin θ . Tick if correct and score one mark.

Ignore small rounding errors. Ignore POT errors in F. If incorrect, write in correct value and do not award the mark.

All values of θ must lie between 900 and 1800; one mark.

Help given by Supervisor, then -1. Excessive help then -2.

Quality of results [2] Judge by scatter of points about the line of best fit. 6 trend points with little scatter scores two marks. 6 trend points with ‘a fair amount of scatter’ scores one mark. 5 trend points with little scatter scores one mark. Shallow curve scores one mark. 4 trend points (or less) scores zero. Considerable scatter scores zero. Wrong trend scores zero.

If wrong angle measured (i.e. values of θ < 900) then cannot judge quality.

Score zero.




Column headings [1] Apply to F only. There must be some distinguishing feature between F and N.

Accept F/N, F (N), F in N, N

F. Allow the unit to be written in words.

Do not allow F, N. Do not allow F/n. Consistency [2]

Apply to F and θ only. One mark each.

All the values of F should be given to one decimal place. Do not accept 0.1 g if spring balance used.

Values of θ must be given to the nearest degree.

(d) Axes [1]

Scales must be such that the plotted points occupy at least half the graph grid in both the x and y directions (i.e. at least 6 squares in the y-direction and 4 squares in the x-direction). Scales must be labelled with the quantity plotted. Ignore units. Do not allow awkward scales (e.g. 3:10, 6:10, 8:10 etc.) Do not allow more than three large squares without a scale marking. Plotting of points [1] Count the number of plots on the grid and write this value by the line. Do not allow plots in the margin area. Check a suspect plot. The number of plots must correspond to the number of observations. Score zero if the number of plots is less than the number of observations. Circle and tick if correct. If incorrect, show correct position with arrow, and do not award the mark. Work to half a small square. Line of best fit [1] Expect to see a reasonable balance of points about the line of best fit. Five trend plots are needed for this mark to be awarded. There must be a straight line drawn through a linear trend of points.

(e) Determination of gradient [2] ∆ used must be greater than half the length of the drawn line; one mark Read-offs and ratio correct (i.e. check that dy/dx has been found and not dx/dy); one mark. Ignore any unit given with the value. y-intercept [1] The value may be read directly or calculated using y = mx + c and a point on the line. If a point on the line has been used, check that there is a valid substitution into y = mx + c. Do not look at final numerical answer if the method of working is correct. Tick the zero on the x-axis if present, or write FO if not.




(f) Gradient equated with mg [1]

If axes reversed on graph then do not award this mark. Value of m [1] Working must be correct (i.e. gradient/g). Allow ecf from incorrect gradient. Intercept equated with k [1] Value must agree with y-intercept on page 4. Significant figures in m and k. Accept 2 or 3 sf only. [1] Units of m and k correct [1] m can be in kg or g (consistent with working). k must be in N. Note: a substitution method in (f) can only score SF and unit marks. [25 marks in total for this question]




9702 PHYSICS

9702/06 Paper 6, maximum mark 40

This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. This shows the basis on which Examiners were initially instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. Any substantial changes to the mark scheme that arose from these discussions will be recorded in the published Report on the Examination. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the Report on the

Examination.




available A B E

Component 6 40 26 23 14


June 2005

GCE A AND AS LEVEL

MARK SCHEME

MAXIMUM MARK: 40


PHYSICS Paper 6


GCE A/AS LEVEL – JUNE 2005 9702 6


Option A - Astrophysics and Cosmology 1 (a) position: on a spiral arm, between ½ and ¾ distance from centre B1 [1]

(b) (i) allow 80 000 → 150 000 light-years B1

(ii) allow 2 → 10 light-years B1 [2]

(c) allow 107 → 109 B1 [1]

2 (a) allow 108 → 1010 K B1 [1]

(b) position marked between 1012 s and 1013 s B1 [1]

(c) result of X-bosons (allow ‘bosons’) B1 at (very) early stages of development of the Universe B1 (X-) boson decays into quarks M1 (slightly) more slowly than its antiparticle decays A1 [4]

3 (a) (i) H0 = (60 × 103)/(3.1 × 1016 × 106) C1

= 1.9 × 10-18 (s-1) C1 age of Universe = 1/H0 (or clear substitution for H0 shown) B1

= 5.2 × 1017 s C1

= 1.6 × 1010 years A1 [5]

(ii) fraction of time = (12600 × 106)/(1.6 × 1010) = 0.79 or 63/80 A1 [1]

(iii) light left galaxy when Universe was much younger B1 (so) ‘looking back’ in time B1 [2]

(b) limit set by how far light can travel M1

during the lifetime of the Universe A1 or galaxies at very large distances are moving very fast so Doppler shifted out of visible [2]

Option F - The Physics of Fluids 4 (a) pressure difference (between upper and lower surfaces) B1 [1]

allow ‘upthrust provided by displaced fluid’

(b) (i) mass = density × volume C1

= 920 × 6.4 × 104 × (28 + d) A1 [2]

(ii) either 920 × 6.4 × 104 × (28 + d)

or 1030 × 6.4 × 104 × d A1 [1]

(c) (i) 920 × 6.4 × 104 × (28 + d) = 1030 × 6.4 × 104 × d C1 d = 234 m A1 [2]

(ii) fraction = 234/(234 + 28) = 0.89 A1 [1]




5 (a) fluid in which there is internal friction B1 either resisting motion of an object through the fluid or resisting movement between layers of fluid B1 [2]

(b) there is no single value for the speed in the pipe B1

(do not allow unqualified ‘constant’) any other comment e.g. volume flow rate takes into account whole flow B1 [2]

(c) (i) pressure (= ρgh) = 1.0 × 103 × 9.8 × 9.1 × 10-2 M1 = 890 Pa A0

some explanation as to why this is the pressure difference B1 [2]

(ii) 1.5 × 10-6 = (π × 0.9 × 10-34 × 890)/(8 × η × 13 × 10-2) C1

η = 1.18 × 10-3 N s m-2 A1 [2] 6 (a) (i) path taken by a particle of the fluid B1 [1]

(ii) each particle can follow only one path B1 [1] (or in terms of tangent being direction of motion, and only one direction)

(b) (in any tube of flow) Av = constant M1

when lines converge, A becomes smaller A1 (so) v must increase B1 [3]

Option M - Medical Physics 7 (a) large/uniform magnetic field applied (to patient) (1)

pulse of radio-frequency waves (1) Causes H-atoms in patient to resonate or vibrate at Lamour frequency (1) H-atoms give off radio-frequency waves (1) RF detected and processed (1) to give positions of H-atoms (1) non-uniform magnetic field enables positions of resonating atoms to be defined (1)

[1 each, any five] B5 [5] (b) e.g. cost, portability of equipment, time taken

[any sensible suggestions, 1 each, max 2] B2 [2] 8 (a) (i) energy deposited in body M1

per unit mass of (body) tissue A1 [2] (ii) effects depend on density of deposition of energy/ionisation B1

some radiations cause greater density of ionisation than others B1 [2]

(b) Radiation has long-term effects M1 any other relevant point e.g. life shortening, hereditary, cancer inducing A1 [2]

9 (a) (i) convex/converging B1 [1]

(ii) focal length (= 100/2.5) = 40 cm B1 [1]

(b) (i) long sight (hypermetropia) B1 [1] (ii) far point is at infinity B1 normal nearpoint is distance 25 cm from eye B1 1/25 - 1/v = 1/40 C1 v = 67 cm nearpoint is 67 cm in front of the eye A1 [4]




Option P - Environmental Physics 10 (a) resources: total energy available/stored in Earth B1

reserves: total energy that can be extracted (economically) B1 reserves less than resources because some fossil fuels not recoverable/too expensive B1 [3]

(b) formation takes place over millions/thousands of years B1

fossil fuels will be exhausted in much less time than this B1 [2] 11 (a) induction compression power EXHAUST open CLOSED CLOSED closed CLOSED CLOSED CLOSED open

[each column 1 mark, max 4] B4 [4]

(b) (i) power is delivered (by a cylinder) on every stroke M1 (so) smoother power output/torque A1 [2]

(ii) improved flow of gases (in and out of cylinder) M1 increases efficiency of engine A1 [2]

12 (a) (i) any agent/substance/waste that is detrimental to health B1

or the environment B1 [2] (ii) 1 man-made: e.g. exhaust gases from cars (anything sensible) B1

2 natural: e.g. volcanic emissions (anything sensible) B1 [2]

(b) carbon dioxide absorbed (by plants) with release of oxygen B1 (transpiration) replaces water vapour (in atmosphere) B1 either increasing CO2 levels would cause temperature changes or anything sensible e.g. reference to biodiversity, weather patterns B1 [3]

Option T - Telecommunications 13 (a) signal sampled at regular intervals B1

signal voltage converted to a digital number B1 transmitted as a series of groups of pulses B1 pulses could be IR pulses in optic fibre (allow any sensible example) B1 any other relevant physics (e.g. sample at twice max frequency, use parallel to series converter) B1 [5]

(b) e.g. can be regenerated to remove noise

data can be added to check for/correct errors [anything sensible, 1 each, max 2] B2 [2]

14 (a) (i) loss of energy/power (in the signal) B1 [1]

(ii) unwanted (random) signal B1 [1]

(b) (i) power/dB = 10 lg(P1/P2) C1

25 = 10 lg (P/(6.0 × 10-19) M1

P = 1.9 × 10-16 W A0 [2]

(ii) allowable loss = 10 lg(7.0 × 10-3)/(1.9 × 10-16) C1 = 136 dB C1

length = 136/1.7 = 80 km A1 [3]

(c) signal amplifier/re-shaper at intervals along the fibre B1 [1]




(d) (i) remains at one point above the Earth (1)

orbits Earth above the Equator (1) period of orbit is 24 hours (1) rotates from west to east (1) [any two, 1 each] B2 [2]

(ii) for satellite, time to travel (2 × 3.6 × 104 km) = 0.24 s B1

for fibre, time to travel 18000 km = 0.06 s → 0.09 s B1 advantage: less built-in delay for conversation B1 [3]

Education

9702 s05 ms_all