Download PHYSICS: Higher Question Paper Mark Scheme Part 2

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]
Page 1
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
Page 2
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)
Page 3
•
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
Page 4
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
Page 5
(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
Page 6
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
Page 7
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
Page 8
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
Page 9
(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]
Page 10
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
Page 11
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
Page 12
(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
Page 13
(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]
Page 14
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
Page 15
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
Page 16
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
Page 17
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]
Page 18
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]
Page 19
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
Page 20
(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)
(ii)
1.68 or 1.7
working is 2(l.16 – 0.64) + 0.64 =
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
Page 21
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
Page 22
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 =
mark
or indication by correct substitution for 1
1
[5]
M28.
neutron becomes proton / neutron emits electron / neutron emits beta particle
gains proton neutral
[1]
Page 23
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]
Page 24
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. =
2 marks for
× mass × speed2
× 5000 × 600 2
N.B. correct answer with the incorrectly recalled relationship
× weight × speed 2 = 2 marks
[3]
M33.
12 100
Page 25
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]
Page 26
Page 27