GCSE EXAMINERS' REPORTS
SCIENCE - PHYSICS
JANUARY 2015
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Unit
Page
Physics 1 Foundation Tier
1
Physics 1 Higher Tier
3
Physics 2 Foundation Tier
7
Physics 2 Higher Tier
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10
SCIENCE : PHYSICS
General Certificate of Secondary Education
January 2015
PHYSICS 1
Foundation Tier
Principal Examiner:
Mr C. Neill
General comments:
Candidates’ knowledge of physics at this level is invariably weak but there were many
positives to be drawn from the answers given in many parts of the paper. The standard of
mathematical work was very variable but on the whole finding a mean, substituting into an
equation and basic calculator work were done well. Recognising the need for the conversion
of units and the taking of relevant data from tables was weak. Answers given in extended
prose were weak particularly in response to the QWC question at the end of the paper.
Q.1
The first question on the paper was answered well by the majority of candidates.
There were a small number of candidates who collectively knew or could work out
that light from the Andromeda galaxy took longest to get to us but they failed to
connect the other three sources to their corresponding times.
Q.2
Hopefully, exposure to the three correct answers in part (a) of this question will help
candidates in the future avoid making erroneous statements such as “It stays at the
same point above Earth at all times”. The question was generally well answered with
most candidates gaining around two out of the three marks available.
Part (b) was reasonably well answered.
Q.3
Most candidates could place all four labels in the correct boxes in part (a) of the
question. It is remarkable that a small number of entrants did not complete all of the
boxes!
In part (b)(i) it was rare to read the correct answer that radioactive decay is a random
process.
In part (b)(ii) most candidates could calculate the mean correctly for one mark. Some
then multiplied it by 60 whilst many others did nothing more. Two marks were
infrequently awarded.
One natural source of radiation could usually be identified to get the mark for the last
part of the question.
Q.4
Both marks were often awarded for candidates correctly completing the table.
In (b)(i) the word “watts” was correctly given and correctly spelt in the vast majority of
answers.
Candidates are getting better at calculating efficiency. Part (b)(ii) was generally well
answered.
Far too many candidates consider it to be acceptable to pay 60 000 p (£600) to use a
1 000 W security light for 4 hours without considering the sensibility of the answer.
The mistake was of course down to the failure to convert 1 000 W into kW in (c)(i).
An error carried forward mark was available for errors of this sort in part (c)(ii)
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Q.5
Successful completion of this question should have made candidates consider
whether wind turbines represent a serious alternative to nuclear power stations in the
provision of a supply of electricity (quite apart from the question of reliability). The
fact that 1 000 of them would be required to replace a single nuclear power station
which would require an area of 700 km2 and that they would need to be replaced
three times in the expected lifetime of one nuclear power station at a cost of over
double that of the nuclear alternative makes you wonder at their feasibility. However,
candidates usually interpreted the last part of the question on the basis of a single
wind turbine being compared with a nuclear power station. The question was not
answered particularly well.
Q.6
Having picked up on the fact that, in the past, candidates fail to differentiate between
the function of pylons and cables, this was a directed attempt to force them into
making the correction. Only occasionally was the correction made successfully.
There was little recognition that “electricity” is sent from power stations to more than
just factories (two or more named consumer groups would have been an acceptable
alternative to the word consumers).
A minority of candidates could state that the name is given to step-up transformers
because it is the voltage that is increased or that the current is consequently reduced
to minimise energy losses.
In part (c) of the question, it was remarkable how many could not place the voltages
in the correct boxes in the diagram but they could then state that the object labelled
as X in the diagram was a step-up transformer.
Q.7
It has frequently been identified in candidates’ answers to nuclear radiation questions
in the past that it could be a cause of cancer because they ionise atoms in cells.
Candidates seemed more reluctant to make these points in answer to a similar
question about X-rays. Often only one mark was awarded to the answers given.
In answer to part (b), the abdomen was usually recognised as the most dangerous
part of the body to be X-rayed but the answers too often failed to highlight the fact
that it administered the biggest dose of radiation from those given in the table.
Part (c) involved some demanding mathematics to which few could respond well.
Q.8
The answers to (a)(i) tended to be centre sensitive. Many candidates could draw a
cyclic loop and draw clockwise arrows on it whilst others failed on both counts or did
not attempt this part of the question.
The diagram gave a big clue as to what would be a suitable answer. “There are
many convection currents, causing air to rise from all parts of the floor” would have
earned both marks but as ever, foundation tier candidates insist on stating that heat
rises as if it were a substance.
Drawing the graph in part (b)(i) was usually well done but some were caught out by
mis-positioning the coordinate (1,150). Schools that do not provide rulers for
candidates are doing them a dis-service when it comes to drawing graphs. A straight
line drawn with a ruler was required here.
The nature of the relationship was generally given in (b)(ii) but the more precise
answer that the power is proportional to the grid area was invariably not given in
answers from foundation tier candidates.
Mathematical extrapolation to get the answer to (b)(iii) was not done well.
Answers to the QWC part (c) were poor. Not unusually the terms conduction and
radiation were conspicuous by their absence but notwithstanding that, many
confused the purpose of the silver foil, claiming that it was there to let heat through
because metals are good conductors! Convection was often mentioned as the
process of heat transfer through solid flooring.
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SCIENCE : PHYSICS
General Certificate of Secondary Education
January 2015
PHYSICS 1
Higher Tier
Principal Examiner:
Mr R. P. Davies
General comments:
The majority of candidates appeared to be correctly entered for this tier of paper and the
demands it provided. However, those at the bottom end of the scale would not have found
attempting this paper to be a positive experience. They would have benefited from the more
structured approach of the FT paper. There were very few gaps on papers with virtually all
questions being attempted by all candidates.
Some general points teachers need to be aware of when preparing candidates for these
exams follow.
1.
The requirements of a question in which the command word is ‘Explain’. These are
always worth at least two marks. In the case of a two mark question, the expectation
is that two relevant, interlinked points are made, with one the consequence of
another. In some instances on the paper, candidates only gave one point or two
points not linked. The points can be given in either order.
2.
Some candidates have difficulty in manipulating equations and in conversions using
SI multipliers.
3.
QWC: Candidates need to be aware of the requirements of each band, and the
consequences of not meeting the criteria in each band. Punctuation, spelling and
grammar cause problems for some candidates even on higher tier. Additionally,
candidates who gave relevant points in their answers penalised themselves by
adding incorrect statements or irrelevant inclusions, which were often more lengthy
than the relevant information they included.
Specific comments:
Q.1
(a)
This first question required the candidates to explain. Candidates referred to
the fact that X-rays are ionising/can cause mutations in cells. An acceptable
second, linked statement would have been ‘so can lead to cancer’. The linked
statements could have been given in any order and so could earn a mark in
the absence of the other statement. Most candidates gave only one of the
acceptable statements.
(b)
Most candidates interpreted the information correctly to identify the most
dangerous type of X-ray. The second linked statement was not always
comparative. There were references to the time taken for the X-ray to decay.
(c)
(i)
The majority of candidates arrived at the correct answer. For the
others, common errors were performing the following calculations:
 140  2
 140  3
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(ii)
A mark was available for correctly multiplying the answer in (i) by 3
and another for multiplying by 43 200. About half of the candidates
managed to earn both marks. Others gained one mark for only
completing part of the calculation correctly, e.g.
 70  43 200 = 3 024 000
 3  43 200 = 129 600
A common error made by candidates who earned no credit was to
perform the calculation
Q.2
(a)
(b)
(c)
43200
.
3
(i)
The convection current needed to start near the radiator and be
contained within the room for the first mark. Some started in the
middle of the room; others were drawn outside the room. An arrow(s)
indicating a clockwise direction obtained the second mark.
Anticlockwise arrows were seen as well as arrows in both directions. A
number had lines going up, down and horizontally and these did not
earn credit.
(ii)
The first mark was available for recognising that the air is heated all
along the floor or over a greater area. Statements such as ‘heats all
the air in the room’ did not earn credit. The second mark was obtained
for a linked statement about more than one convection current being
set up. About half of the candidates gained this second mark.
(i)
Most candidates gained full marks for plotting the graph. Some only
earned two marks because of one of the following errors:
 failure to plot the (1,150) point correctly;
 not continuing the line back to (0,0);
 not joining the points in a straight line with a ruler.
(ii)
Most candidates could describe that power increases with area but
only about half went on to state the proportional relationship.
(iii)
The instruction was to use the data. Some candidates actually
extended the y-axis and extrapolated to find a value only to give a
wrong value. Surprisingly, less than half earned this mark.
Most candidates earned marks in the bottom band with some getting into the
middle band. Very few achieved top band marks. These candidates covered
the required content in some detail and made little or no written
communication errors.
The following errors were seen:
 not using capital letters at the start of a sentence or even at the start of
their answer and random capitals appearing in the middle of sentences;
 limited use of full stops;
 spelling mistakes;
 irrelevant or incorrect inclusions;
 references to convection through the floor;
 describing the silver foil as a good reflector of hot air;
 significant omissions, typically, energy flows from higher to lower
temperatures through the concrete floor.
A typical lower band answer referred to the foam as being an insulator (this was
given in the labelling) and the foil reflecting heat.
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A typical middle band answer included statements about the foam reducing heat loss
through the concrete by conduction and the foil reflecting radiant heat back into the
room.
A typical upper band response would have included statements as for the middle
band but would have included that heat loss occurred through the concrete because
energy flows from a higher temperature to a lower temperature. This fact was usually
omitted however.
Q.3
(i)
Many candidates gained full credit here. However, a statement that referred
to the prevention of heat loss did not gain the third mark, since heat loss can
only be reduced.
(ii)
A surprising number of candidates failed to complete the calculation correctly.
Errors seen were:
 3 950  92



Q.4
3950
92
3950
0.92
3 950  92  100
(iii)
There are two routes through this multistage calculation. Both routes require a
conversion of units. This was not always done or incorrectly done. Candidates
need reminding that the SI multipliers are given on page 2. One route through
the calculation required a multiplication of 230  80 to give the maximum
power provided to each home. This was usually calculated correctly. This
value should then have been divided into their answer from part (ii). The two
numbers needed to be in compatible units and that caused a problem.
The second route required the conversion of MW into W. This caused a
similar problem to the first method. The value needed to be divided by 230
and again by 80. Candidates who decided on this latter method rarely divided
by both values.
(i)
Only a minority of candidates obtained this mark. Some omitted to give a unit,
others wrote the unit as light years (as written in the stem), while others
attempted to write the number out in full making an error in the number of
zeroes after 222.
(ii)
Many candidates referred to absorption of light, fewer went on to say at
certain wavelengths and it was very rare to see that this was due to atoms of
gas. Some candidates referred to absorption of gases.
(iii)
Most candidates recognised that the expansion of the Universe contradicted
Steady-State theory but they had difficulty in linking this fact with CMBR and
red shift.
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Q.5
Q.6
(i)
The equation was listed on page 2 but it needed to be manipulated to make
wavelength the subject. Most candidates could do this but a significant
minority were unable to. Then a conversion was required from GHz to Hz or
m/s to Gm/s. This was usually omitted too. Therefore most candidates only
earned two marks for an answer of 2  10n if clear working was shown.
(ii)
This caused candidates the same difficulties as above i.e. manipulation and
conversion. Another error was incorrect rounding of the final answer. Again
two marks were awarded for an answer of 1.17  10n as long as clear working
was shown.
(a)
It was expected that candidates would refer to providing electrical power to
more than just homes. The term ‘consumers’ was not well known. A minority
of candidates included a statement about its ability to meet a fluctuating
demand or to maintain a reliable supply.
(b)
This was the third question that required conversion between units and higher
tier candidates should be able to cope with this demand.
(c)
(i)
Nearly all candidates calculated the total time of generation for the
week shown in the table. The majority converted this to hours and
went on to calculate the energy output for the week.
(ii)
Two conversions were required – MWh to kWh and pence to £. An ecf
was allowed from (b)(i). There was also an ecf allowed within the
calculation for an incorrect value of the electricity supplied to the grid.
A minority of candidates earned full marks.
This QWC question was answered better than the one in Q.2. Most
candidates could comment on the reliability of the output of wind and consider
environmental issues. The quantity and detail of the points made determined
whether the lower or middle band was awarded. Some candidates confused
the gases that contribute towards global warming and acid rain. Some
candidates wrote at length about nuclear power but this was not required. The
information about the power output of a nuclear power station was only given
so candidates could make a comparison between the numbers of wind
turbines and nuclear power stations required to meet the demand of the
National Grid. Some candidates included these calculations in their answer so
met the demands of entering the higher band. Others made vague statements
about needing more wind turbines than nuclear power stations.
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SCIENCE : PHYSICS
General Certificate of Secondary Education
January 2015
PHYSICS 2
Foundation Tier
Principal Examiner:
Mr R. P. Davies
General comments:
The requirements of a question in which the command word is ‘Explain’ do not appear to be
understood by many candidates. These are always worth at least two marks. In the case of a
two mark question, the expectation is that two relevant, interlinked points are made, with one
the consequence of another. In some instances on the paper, candidates only gave one
point or two points not linked.
QWC: Candidates need to be aware of the requirements of each band, and the
consequences of not meeting the criteria in each band. Punctuation, spelling and grammar
cause problems for candidates.
Specific comments:
Q.1
(a)
It could be considered that this depended on recall of knowledge but the
answers for the second and third rows could have been deduced from the
other two effects in each of those lines. For example, in row three, both the
thinking and braking distance decrease so the overall stopping distance must
also decrease. It was surprising how many candidates did not gain credit or
earned a mark of 1 for completing the table.
(b)
(i)
Candidates were required to select the appropriate distance from the
table to complete the calculation. Many could do this. Others decided
to use a distance of (75-18) or (75+18).
(ii)
Many selected the appropriate distance and substituted correctly.
Some lost a mark because they did not copy the correct number of
zeroes after the 9 on the answer line. Others performed the following
incorrect calculations:
 1 200  18
 1 200  93
(iii)
About half of the candidates completed this calculation correctly.
Some substituted incorrectly and worked out the value of
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5
.
30
Q.2
Q.3
(a)
There were three gaps and three words to choose from. The temptation to
use all of the words was too strong for some candidates despite the question
stating that each word could be used more than once or not at all. This
demonstrates a lack of knowledge and understanding of the topic. The
requirement was to insert the word current in both parts (i) and (ii).
(b)
(i)
Most candidates calculated the current correctly to earn both marks.
(ii)
About half of the candidates realised that this value was double the
previous answer. Many of the remaining candidates wrote down the
same answer as in (i).
(iii)
Candidates were expected to multiply their answer in (i) by 12 to earn
credit here. Some candidates substituted into the equation the current
value from (ii).
(c)
Most candidates recognised that the current would decrease to earn a mark.
Very few could progress to state the decrease would be by a factor of 4.
Reasons given included that the current would decrease through the first bulb
and again at the second bulb. Some thought as resistance increased, so did
the current.
(a)
(i)
It was surprising how many candidates failed to arrive at the correct
answer. A common error was to divide the two speeds i.e.
Q.4
20
.
5
(ii)
Most candidates completed this calculation correctly by multiplying
their answer for (i) by 60.
(iii)
Again, most candidates found the value of the force to earn a mark but
very few could state the unit.
(b)
Most candidates recognised that the force would increase but few could
provide a linked statement as to why this happened.
(c)
Nearly all candidates gained both marks.
(a)
The table was usually completed correctly to earn both marks.
(b)
Helium was a more common response than hydrogen.
(c)
Most candidates could complete the nuclear symbol for lead correctly but
then made mistakes in completing the equation that followed. A minority of
candidates deduced that 2 neutrons were produced in the reaction, with 1 and
3 being common errors.
(d)
Candidates mixed up the functions of moderators and control rods.
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Q.5
(a)
Candidates did not appreciate that the bigger sample size would reduce the
effect of anomalies.
(b)
There were errors in plotting the points due to misreading the scale on the
y-axis. A smooth curve through all points was expected. Some lines were
clearly drawn as a series of straight lines from point to point; others missed
too many points or were wavy in nature.
(c)
(i)
A range of values between 3.6 and 4 were accepted and most
answers fell within these boundaries.
(ii)
Most candidates attempted to find the number of rolls after which
200 dice remained. However, the horizontal line (to intercept with the
curve) was drawn at values ranging from 175 to 200 dice.
(iii)
Most candidates responded with an appropriate suggestion.
(iv)
About half of the candidates could use the graph to find the number of
rolls. Most comments referred to 100 being a quarter of 400, with very
few realising that this was equivalent to two half-lives.
(i)
Many candidates showed the decay series in a form such as
80-40-20-10. Some then made an error in stating this was 4 half-lives.
Others were not aware of the next step in the process i.e. to divide the
time by the number of half-lives.
(ii)
To identify 2 further half-lives would occur and then calculate the new
time was beyond most candidates.
(iii)
Very few candidates knew the unit of activity.
(d)
Q.6
(a)
Most candidates earned a mark for substituting the mass of 80 kg into the
equation correctly. However, values for the resultant force were roughly
equally proportioned between 200, 600, 800 and 1 000 N. Some candidates
decided to multiply the values even though the given equation clearly showed
division was required.
(b)
Most candidates were limited to a mark in the lower band. This was for
recognising that the air resistance increased when the parachute opened. It
was rare to see anything else that was creditworthy.
The following errors were seen:
 not using capital letters at the start of a sentence, even at the start of their
answer and random capitals appearing in the middle of sentences;
 limited use of full stops;
 spelling mistakes;
 references to mass instead of weight;
 references to mass/weight changing;
 comparing weight and gravity;
 believing the parachutist moves upwards when the parachute opens;
 inclusion of irrelevant detail e.g. a description of the descent before the
parachute opened.
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SCIENCE : PHYSICS
General Certificate of Secondary Education
January 2015
PHYSICS 2
Higher Tier
Principal Examiner:
Mr. C. Neill
General comments:
The paper proved to be quite demanding for the majority of candidates with about 50%
success in answering the questions over all. Graph drawing skills are underdeveloped
amongst the candidature whilst basic mathematical skills are reasonably good. Multistage
calculations are still not developed sufficiently well (as demonstrated in question 5 but the
early part of question 2 was generally well done). The quality of written communication
whilst improved grammatically, demonstrated that candidates need to remain focused on
what the question is asking and to refrain from over-writing. Understanding of electrical
principles is in need of improvement, as demonstrated in question 3, but the candidates’
performance on the mechanics questions (4 and 5) gives even more cause for concern.
This is an area of the specification which has historically been a strongpoint, but is now
proving to be an area of weakness.
Q.1
In answer to part (a), very few candidates could identify with reducing the effect of
anomalies as the reason for taking multiple groups’ results, but other answers of
lesser quality were accepted.
Point plotting on the grid in part (b) was done well but too many candidates insisted
on the line actually passing through the coordinate (5,190) which is a little high of a
best fit curve. Too many candidates still join point to point (with or without a ruler)
and some just joined the first point to the last with a ruler. The ideas behind judging
which lines to draw for a given set of plotted points are not understood.
In answer to part (c)(i), answers between 3.6 and 4 were acceptable and most
answers fell in that range.
When using the graph to give an answer to the same question in part (c)(ii), a
significant number of answers were based on the idea that the half-life would be 4
and a line was drawn up the curve from that value to find an ordinate value of around
190 dice remaining. Clearly they did not understand the idea of half-life.
In (c)(ii), it was rare to find an answer that identified that one quarter of the dice
remained after two half-lives.
A minority of answers identified the half-life of protactinium to be 70 s, from 3 halflives having elapsed. Many had no idea of how to answer this question [(d)(i)].
As a consequence of the statement above, there were few correct answers to (d(ii))
which exhibited a significant correspondence between the two successful answers.
A large percentage of candidates knew that the unit of activity of a radioactive source
is the Becquerel (however spelt).
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Q.2
A good number of candidates realised that the resultant force had to be calculated
before an acceleration could be calculated. There were many good answers to this
part of the question.
The quality of punctuation and grammar that is used in answers to QWC questions is
significantly better than it used to be. The quality of the content of what is written has
also improved. However, in this question far too many candidates wanted to relate
everything that they knew about a falling parachutist. As a consequence, the
relevant part of the answers often started near the bottom of the page and what was
given prior to that gained no credit. There were many good answers and it was good
to see that included in them was reference to the resultant force acting upwards after
the parachute was opened and the reduction in air resistance with decreasing speed
led to a small final terminal velocity.
Part (b)(ii) showed huge variability between the quality of answers. Many good
answers were seen.
Q.3
Values of power and resistance being given in the question led most candidates to
use the correct equation to find the current in each lamp but most of them failed to
realise that the ammeter reading would be double that answer.
The answers to (a)(iii) were interesting, in that, in most cases, those candidates who
successfully gave an answer of 3 A to (a)(ii), used that value to (erroneously) find the
voltage of the battery whereas those who failed to double their answer from (a)(i) into
(a)(ii) gained success in answering (a)(iii).
Not many answers were seen in (b)(i) that identified the change in ammeter reading
with the reduction in current yet alone linking that to an increase in resistance. Other
routes to the answer were possible but were very rarely seen.
The most common mistake made in (b)(ii) was to use P = VI for which the answer to
(a)(iii) was used without the candidate realising that the supply voltage needed to be
halved to find the power of each lamp. A calculation based on P = I2R would have
been a safer route through the question but not many candidates adopted it.
Part (b)(iv) was generally answered successfully.
Q.4
For the answer to part (a), the least meaningful format of “action and reaction are
equal and opposite” was most commonly quoted and gained both marks. The more
elaborate “if body A exerts a force on body B then …..” was sometimes seen but a
number of the candidates who gave it in this form went on to state that the resultant
force was zero (or equivalent) suggesting that the two forces act on the same object.
One mark was withheld for doing this.
Applying (a) into (b)(i) was beyond most candidates. This was poorly answered with
the most common mistake being that the force direction was down (or even South)
but even the weight of the bag was not calculated successfully in most cases.
The acceleration equation could not be simply rearranged to find the velocity
achieved after 0.8 seconds.
Part (b)(ii) was really poorly answered.
Part (b)(iii) was poorly answered, mainly because it was taken that the velocity
calculated in part (ii) was the acceleration.
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Q.5
Despite the word total having been italised in the question, most candidates only
calculated the kinetic or potential energy of the rollercoaster car. The small number
of candidates who correctly answered part (i) usually answered (ii) correctly too. The
error carried forward principle was applied into part (ii) from (i) and allowed a good
number of candidates to earn full credit in (ii).
The answers to part (iii) were not convincing. Some talked about gravity being
responsible or that the height of the next peak (?) needed to be lower than the last
(a remnant of a previous question?)
Q.6
The left hand side of the equation was given in the question but some still got it
wrong. A small percentage of candidates failed to calculate the mass numbers of
krypton and barium. A significant percentage of candidates could not balance the
equation by identifying 2 neutrons were released in the reaction. Most candidates
had a basic understanding of the action of the moderator and of the control rods. At
the high end of attainment were those candidates who could tell that only one
neutron should go on (on average) to produce further fission to avoid an uncontrolled
reaction and that slowing down the neutrons is necessary to achieve capture by the
uranium nuclei. The standard of spelling, punctuation and grammar was noticeably
better than in the more distant past on this paper.
gcse-science-physics-report-jan-2015
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