mass in kg (i.e. 0.0007 or 0.7/100000) each gains 1 mark squaring the speed of light but 6.3 × 10...

Physics P2 Higher Mark Scheme Part 2

M1. (a) ordinary cell has higher voltage (normally / at start) or ordinary cell 1.3V nicad 1.2V (normally / at start)

for 1 mark

voltage of ordinary cell falls more slowly

gains 1 mark

(accept ordinary cell lasts longer) but as above with relevant quantification e.g. falls to zero in 60 seconds compared to 6 seconds or nicad falls to zero 10 times as fast

gains 2 marks 3

(b) (i) answer in range 32-34 (seconds) (inclusive)

gains 1 mark

but answer in range 22-24 (seconds) (inclusive)

gains 2 marks

(ii) 12 (seconds)

gains 1 mark

but 2 (seconds)

gains 2 marks 4

(c) resistance of the lamp / filament changes / increases

gains 1 mark

but resistance of the lamp / filament decreases

gains 2 marks

because the temperature of the filament falls / filament cools

for 1 mark 3

[10]

M2. (i) (fast moving) electrons (from the nucleus) (allow negatively charged particles)

for 1 mark 1

(ii) protactinium has one neutron fewer protactinium has one proton more (credit has different numbers of neutrons / protons with one mark)

for 1 mark each 2

[3]

M3. (a) indication (in writing or on graph) of finding point where radiation is halved (e.g. to 24 [from an initial 48]) and relating to the time difference between the two points

gains 1 mark

but 4.2-4.8* (*i.e. in this range, including extremes)

gains 2 marks

units billions of years

for 1 mark 3

(b) ¾ or 75% [allow ecf from (a)]

for 1 mark 1

(c) (i) idea that the intermediate nuclides are relatively short-lived

for 1 mark 1

(ii) idea that ¼ has decayed or ¾ remains

gains 1 mark

but read graph for radiation level of 36 (stated or shown on graph itself)

gains 2 marks

but 1.6-1.8* (billion years) (* i.e. in this range, including extremes)

gains 3 marks 3

[8]

M4. (a) idea that balanced by friction force* / pushing force equals friction force (*note “balanced” by unspecified force) or specification of relevant force but no reference to balancing in both 1(a) and 1(b) gains 1 mark overall

for 1 mark 1

(b) balanced by upwards force of table*

for 1 mark 1

(c) makes it (slightly) warm / hot or wears it away (slightly) / damages surface

for 1 mark 1

[3]

M5. ideas that

• formed from dust/gases

• pulled together by gravity

• massive so very large gravitational forces (pulling inwards)

• hydrogen → helium / fusion releases energy [not fission or just „nuclear‟]

• high temperature creates high pressure (pushing outwards)

• long period when forces balance

• then expands → red giant / red star

• then contracts to (dense) white dwarf / white star

[credit if massive enough / more massive than sun, red giant → supernova → (very dense) neutron star but do not accept w.r.t. Sun itself]

[The whole of the (non bracketed part of) each idea must be present in some appropriate for in of words for each mark to be credited. To gain more than a single mark ideas must also be in correct sequence and/or appropriately related.]

any six 1 mark each [6]

M6. (a) acceleration =

or

gains 1 mark do not penalise if both of these present but ‘change in’ omitted from formula

but 2.5

gains 2 marks

unit m/s2 or metres per second squared

or metres per second per second

or ms–*

for 1 mark 3

(b) evidence of using area under graph or distance average speed × time or

10 × 4 ×

gains 1 mark

but 20

gains 2 marks

units metres / m–2*

for 1 mark 3

(c) force = mass × acceleration or 75 × 25

gains 1 mark

but 1875

gains 2 marks

*NB Correct unit to be credited even if numerical answer wrong or absent. 2

[8]

M7. (a) evidence of

gains 1 mark

but

490

gains 2 marks

but

4900

gains 3 marks

units cm3

for 1 further mark 4

(b) some of radioactive solution gets into cells/body organs some of radioactive solution gets into urine (in the kidney) the radioactive solution becomes less radioactive during the test variability in readings

in any order for 1 mark each 3

(c) ideas that

• won‟t lose (too) much radioactivity during the test

• won‟t stay radioactive/harm cells for too long after test is over

for 1 mark each 2

[9]

##

(a)

[Accept He2+ for α]

each for 1 mark 4

(b)

[Accept β for e]

each for 1 mark

4

(c) (i) beta/ β alpha/ α alpha/ α beta/ β beta/ β but alpha/ α alpha/ α beta/ β [i.e. consistent for 1; consistent and correct for 2]

gains 2 marks 2

(ii) ideas that • many thorium atoms because they take so long to decay* • (many lead atoms because) the thorium has been decaying for so long/for billions of years or (because) the rock is so/very/billions of years of years old • many lead atoms because this is the stable end product [of the decay series] • few atoms of other isotopes because they decay so quickly*

[*N.B. credit answers in terms of half-life]

any three for 1 mark each 3

[13]

##

(a) ideas that greater speed means more kinetic energy

gains 1 mark

but any evidence of the formula ½ mv2

but making the case that kinetic energy depends on the speed squared

gains 3 marks

or that 22 = 4 3

(b) (i) any evidence of concept of momentum or mass × speed (or velocity) in words or figures e.g. 9.5 × 20 or 0.5 × 40

gains 1 mark

but correct values for momentum of lorry and car i.e. 190 and 20 [ignore units]

gains 2 marks

but initial momentum correctly calculated 170 or 190 – 20

gains 3 marks

THEN evidence when calculating final speed of idea that momentum is conserved use of combined mass

each gain 1 mark

but 17 [or 0.1 × figure for initial momentum] (NB direction not required)

gains 3 marks 6

(ii) kinetic energy is lost

for 1 mark

[credit (some kinetic) energy transferred as heat/sound] [NB Accept only answers in terms of energy as required by the question]

1

[10]

M10. (a) it use E = mc2

mass in kg i.e. 0.001 ×

each gains 1 mark

but 000007

gains 2 marks

2.1 × 103

gains 3 marks

evidence of 0.000007

mass in kg (i.e. 0.0007 or 0.7/100000)

each gains 1 mark

squaring the speed of light but 6.3 × 1011 (credit alternative ways of stating this)

gains 3 marks

units J/joule

for 1 further mark

(N.B credit kJ, MJ, GJ but check power of 10 for full credit) 4

(b) (i) idea that the bigger the mass the shorter the life

gains 1 mark

but idea that decrease in life is much more than proportional to increase in mass or more than proportional to mass2

gains 2 marks 2

(ii) ideas that: greater mass means greater core temperature/pressure greater core temperature/pressure means greater rate of fusion increase in mass produces a proportionally much greater increase in the rate of fusion

each for 1 mark 3

[9]

M11. (a) any evidence of: momentum = mass × velocity (words, symbols or numbers) appropriate re-arrangement mass as 0.05kg

each gains 1 mark

but 800

gains 4 marks 4

(b) (i) any reference to friction with air/air resistance

gains 1 mark

but idea that friction with air/air resistance is high (at high speed)

gains 2 marks 2

(ii) any evidence of: k.e. v2 or k.e. = ½ mv2

final k.e. initial k.e. either initial or final k.e. correctly calculated (i.e. 16000; 10240)

each gains 1 mark

but (0.8)2

gains 3 marks

but 64%(credit 0.64)

gains 4 marks (also credit e.c.f) 4

[10]

M12. (a) evidence of conclusion 4 × 1.007825 or 4.0313

each gain 1 mark

based on use of data that there is a (very small) loss of mass or 0.0276 but a loss of mass of 0.0276 for every helium atom or 0.69%/0.7%

gains 3 marks 3

(b) idea that loss of mass results in release of energy

gains 1 mark

but small loss of mass results in huge energy release

gains 2 marks 2

[5]

M13. (a) any two from

(risk of) cutting (through the) cable

accept cutting the wire

grass may be wet

or it may rain

wires may be loose (because cable experiences a lot of movement)

accept cable may be loose

(risk of) touching exposed part(s) 2

(b) some current will go through (the rest of) the lawnmower / the user / to earth

do not credit any reference to the electromagnet 1

(c) (i) charge = current × time

or any transposed version accept Q = I × t or any transposed version accept C = A × s or coulombs = amperes × seconds or any transposed version

or

but only if subsequently used correctly 1

(ii) EITHER 1200 microcoulombs / μC

or 1.2 millicoulombs / mC or 0.0012 coulombs /C

3

OR correct arithmetic

either converting milliamps to amps and milliseconds to seconds

or correct multiplication

unit given as coulombs /C or millicoulombs / mC or microcoulombs / μC

example : charge = 30 × 40 = 1200 millicoulombs should be credited with 2 marks

1

[7]

M14. (i) EITHER 30000 (2) joules/J (1)

or 30 kilojoules/kj 3

OR power × time = energy

1

time = 120 (seconds) 1

(ii) vibration (of the food processor / some part of the food processor / the food) 1

[4]

M15. (a) Formula mark P = V × I

accept P = VI or W = V 5 A or any transformation 1

Substitution mark I = 900 ÷ 230 1

Calculation mark 3.9

accept 3.9 or 3.91 or 4 for three marks with no working 1

(b) 900 + 1300 = 2200 ÷ 230 = 9.6

accept 9.57 to 9.6 or 10 for both marks with no working 2

(c) 1.2 + 0.45 = 1.65 1

× 0.5 = 0.825

accept 0.8 or 0.83 for both marks with no working 1

(d) any one from

use less energy (to cook something)

accept fewer energy losses or use less electricity

cook faster

do not credit a cost argument about buying two different ovens

1

[8]

M16. (a) (i) work = force × distance

or any correctly transposed version e.g.

force =

or in correct units throughout e.g.

J = N × m

or in acceptable abbreviations e.g.

W = f × d

do not credit W = Nm or any other

ambiguous or unclear response

do not credit

unless subsequent calculation shows understanding 1

(ii) EITHER

3.7 (m) 2

OR

(distance =) 1

(iii) 2000 J

unit required 1

(b) EITHER

20 3

OR

speed 2 = 600 ÷ 1.5

or speed2 = 600 ×

or speed2 = 400

or speed2 = KE ÷ mass 1

metres per second

or m/s 1

(c) any three from

deceleration (would be) (very) great

or rate of change of speed / velocity would be (very) great

(because) F = ma

or (because) force is proportional to deceleration / (negative) acceleration

(so the) force (on Susan / the rope) would be (very) great

do not credit she would be hurt

do not credit just the rope could snap

the rope may exceed its elastic limit 3

[10]

M17. (a) (i) P = V × 1

or equivalent

credit a triangle if part (ii) correctly uses the relationship

credit power = volts × amps or watts V × A

do not accept C for current 1

(ii) (P = 230 × 10 =) 2300

credit 2.3 1

W or J/s

kW 1

(b) (i) 15 A

credit 13 A or amps 1

(ii) any three from

earth

any short (to the metal tank) causes fuse to blow

fuse is in the live wire

to prevent damage to the heater

credit to stop the current 3

(c) (i) V = I × R

or equivalent

credit a triangle if part (ii) correctly uses the relationship 1

(ii) (230 = 10 × R =) 23

ohms or Ω

2

[10]

M18. (a) F 50 cm on first part of graph

tolerance + or – 3cm 1

(b) S at the far right

credit anywhere to right of last trough 1

(c) M on any two tops of peaks or bottoms of troughs

both are required for the mark M needs to be central to the trough or peak, except if F is in the way in one case

1

[3]

M19. (i) either 210 C

3

or 1260 (joules of energy transferred)

unit not required 1

210 1

coulomb(s) C

allow J/V 1

(ii) either 0.7 A

3

or

charge = current × time

or 210* = current × 300 1

or Q = It

or* same as candidate’s answer to part (a)(I) provided correct unit given in part (a)(i) or* as follows from above

1

current = 0.7* amp(s) or A

1

[6]

M20. (a) either gravity

1

due to mass of the Earth

or (the) interaction / attraction between the (1)

mass of the block and the mass of the Earth (1)

1

(b) (i) 4.5 N

unit required accept equal to weight (lifted)

do not credit ..mass.. 1

(ii) the forces are balanced

accept because the block is not accelerating

accept because the block is moving at a steady speed (in a straight line) accept because the block’s velocity is constant

1

(c) (i) either

4.05 J 3

or work (done) = force (applied) × distance (moved in the direction of the force)

or work =4.5 ×0.9 note ‘= 4.5 × 0.9’ is not an equation

1

= 4.05 1

joules or J or newton metres

405 J will be a common answer it gets (1) (for the unit) if correct equation is not shown but (2) otherwise

4.5 ÷ 0.9, or variations on this theme, get (1) (for the unit) at most

1

(ii) 4.05 J

or same as the answer to (c) (i) provided that the same unit for energy is shown in both cases

1

(d) 4.16

accept 4, 4.2, 4.17, 4.16 1

[10]

M21. any one of

* between (stage) 2 and (stage) 3 * (in) the main sequence * (in) the main stable period * (it is a) yellow dwarf

[1]

M22. (a) sensible scales

full use of y axis 1

completely accurate plotting 1

a smooth curve going through all bar one of the points

do not accept a dot-to-dot graph if two parts shown for curves accept the more correct

1

at least one line or a clear mark showing how to obtain the half life from the graph and obtaining between 13 and 15

at the bottom of the page cross or ticks in the order of the mark scheme

1

(b) (i) to let the beta particles get through

accept must be there to let the radiation through or if thick they may be stopped

1

(ii) alpha particles would be stopped by the glass or cannot penetrate glass

do not accept alphas are weak 1

(c) (i) it will give more counts per minute for a small quantity or it does not last so long so may not be as dangerous

accept answers in terms of 5 years assume it refers appropriately

1

(ii) it will not be there long enough to act as a tracer or it could cause radiation damage as all its activity will be in the first place it enters the system

accept answer in terms of 5 seconds

accept not there long enough to work assume it refers appropriately

1

[8]

M23. (a) (i) power ÷ voltage = current or 2800 ÷ 240 = 11.6 – 11.7 or 12

2 marks for correct answer 1 mark for 2.8 ÷ 240 2

(ii) resistance = voltage ÷ current

240 ÷ 11.7

(efc here) 1

20.5 or 20.57 or 20.6 or 21

2 marks for correct answer 1

ohms or Ω

do not credit R 1

(b) 850 ÷ 1500 × 100

marks only available for division of power 1

= 56.7

2 marks for correct answer for 1 mark accept 5670

1

[7]

M24. (a) 3.125

accept 3.1 or 3.12 1

(b) plotted at 1. 15 – 1.17, 1.24 – 1.28

across on the second from 1.2, up between first and second line

1

sketch curve steeper near 0.64 s fairly smooth curve bending 1

to become pretty well horizontal at 1.16, 1.25 1

(c) (i) 1.68 or 1.7

working is 2(l.16 – 0.64) + 0.64 =

(ii) 2.5 m unit required

consequential marking applies here 1

(d) X1 at 0.64 s, 0 m

it is in contact with the floor or the ball changes direction or the downward force is balanced by the reaction of the floor

accept the ball is hitting the floor

do not credit it has hit the floor 1

X2 at 1.16 s, 1.25m it is at the top of its bounce

accept the ball changes direction or has run out of KE 2

[8]

M25. (a)

3

one mark for each symbol allow more than 2 cells joined

max. 2 marks if symbols incorrectly allow rheostat arrow in either direction

(b) current will decrease 1

since resistance greater 1

[5]

M26. (a) materials produced when earlier stars exploded

accept the Sun is a second generation star

accept formed from nebulae 1

(b) Quality of written communication: 1 mark for correct sequencing balanced forces → expansion → contraction / explosion

1

any five from

gravity pulling matter together

accept idea that a star is very massive so its force of gravity is very strong

high temperatures that create expansion forces

nuclear fusion releases energy that causes the very high temperatures

these forces balance

star expands greatly

since expansion is greater than gravity

accept fuel runs out

forms a red giant

give no further marks if red giant → white dwarf, red dwarf

etc

collapses inwards and explodes outwards

called a supernova

neutron star may form

leaves a small, dense object (a black hole)

accept nothing can escape from it 5

[7]

M27. 1050 4

kg

if answer incorrect then kinetic energy = mv2 or

accept indication by correct substitution for 1 mark

accept 900 for 1 mark

accept m = or indication by correct substitution for 1 mark

1

[5]

M28. neutron becomes proton / neutron emits electron / neutron emits beta particle

gains proton neutral [1]

M29. (i) (strontium-90) beta rays partly absorbed by aluminium

accept gamma rays not absorbed and alpha all absorbed

if phosphorus -32 then one mark max for beta ray explanation

1

long half life means it can be used for a long time 1

(ii) (technetium-99) (gamma) rays will pass out of body / less likely to be absorbed

accept (gamma) less damaging or alpha / beta will damage cells if cobalt -60 then one mark max for gamma ray explanation

1

short half life means it will not affect body over a long period 1

[4]

M30. (a) (i) two protons 1

2 neutrons

if neither point gained allow 1 mark for helium nucleus 1

(ii) electron 1

(b) neutron splits (to form proton and electron) 1

[4]

M31. Quality of written communication: One mark for using correct scientific sequence : gravity → fusion → balance

1

any four from

• (dust and gas) pulled together by gravity

• (star formed when) it is hot enough

accept (as mass is pulled together) it gets very hot

• hydrogen (and helium) nuclei fuse

• (these nuclear fusion reactions) release the energy / heat / light (which is radiated by stars)

• energy causes expansion

• gravitational pull is balanced by the expansion (force) 4

[5]

M32. 900 000

correct with no working = 3 if answer incorrect, allow:

1 mark for K.E. = × mass × speed2

2 marks for × 5000 × 600 2

N.B. correct answer with the incorrectly recalled relationship

× weight × speed 2 = 2 marks [3]

M33. 12 100

correct answer with no working = 3 if answer incorrect, allow 1 mark for force = mass × acceleration 1210 × 10 = 2 force / weight = mass × gravity is neutral

N.B. no marks for correct answers with incorrectly recalled relationship

[3]

M34. (i) 7 or 8 1

correct data extracted from graph e.g. takes 8 days to drop from 50 to 25

allow appropriate annotation of graph 1

(ii) long enough to destroy cancer cells

do not accept dangerous unqualified 1

but short enough to minimise damage to surrounding tissues 1

[4]

M35. (i) 7 or 8 1

correct data extracted from graph e.g. takes 8 days to drop from 50 to 25

allow appropriate annotation of graph 1

(ii) long enough to destroy cancer cells

do not accept dangerous unqualified 1

but short enough to minimise damage to surrounding tissues 1

[4]

mass in kg (i.e. 0.0007 or 0.7/100000) each gains 1 mark squaring the speed of light but 6.3 × 10...

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Transcript of mass in kg (i.e. 0.0007 or 0.7/100000) each gains 1 mark squaring the speed of light but 6.3 × 10...