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General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
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SCIENCE
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Paper 5125/01
Multiple Choice
Question
Number
Key
Question
Number
Key
1
2
3
4
5
C
D
D
B
D
21
22
23
24
25
C
A
A
B
D
6
7
8
9
10
B
B
B
A
A
26
27
28
29
30
A
C
D
B
B
11
12
13
14
15
C
C
C
D
B
31
32
33
34
35
A
A
B
B
D
16
17
18
19
20
B
C
A
A
D
36
37
38
39
40
A
B
D
B
A
General Comments
Candidates found Questions 1, 3 and 14 to be straightforward, with Questions 2, 5, 7, 9, 21 and 22 also
producing a correct response from a significant number of candidates. Some more able candidates had
difficulty with Questions 13 and 16. Other questions, for example Questions 10, 15, 19 and 24
discriminated well between the more and less able candidates.
Comments on Specific Questions
Question 1
A small number of more able candidates incorrectly chose option D.
Question 2
This was well answered and showed very good discrimination with option A the favoured choice of weaker
candidates.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
Question 3
Candidates found this to be very easy with option B claiming the majority of the incorrect responses.
Question 4
This was well known and showed very good discrimination with less able candidates incorrectly choosing
option A.
Question 8
This question discriminated well with less able candidates of the opinion that ‘contains mercury’ is the
property essential to a clinical thermometer, option A. A number of the more able candidates incorrectly
chose option C.
Question 9
This was well known. Option B was the most popular incorrect response.
Question 10 and 11
These questions both showed very good discrimination with option B the most popular incorrect choice by
less able candidates in Question 10 and in Question 11 it was option A.
Question 13
The speed of sound in an unfamiliar unit, cm/s, found stronger candidates equally divided between the key,
option C, and, having ignored the unit, option D. Most of the less able candidates opted for the more familiar
expression of option A.
Question 14
Option C was the most popular distractor.
Question 16
This question was not understood. Option D attracted more responses from, mainly less able, candidates
than did option B, the key. Option C attracted a large number of the more able candidates.
Question 17
The hazards of using electricity in the home are still not appreciated by candidates, many of whom chose
options A and B.
Question 19
This question showed very good discrimination with option D the preferred choice of less able candidates.
Question 23
While most candidates got this question correct (on water absorption by plants), significant numbers had the
water concentrations reversed.
Question 25
Some candidates do not realise that osmosis always refers to the movement of water.
Question 26
Most candidates understand that carbon dioxide can limit the rate of photosynthesis.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
Question 27
This question required careful reading. The majority of candidates who got it wrong had the answers exactly
reversed.
Question 28
Here again, misunderstanding of osmosis led to candidates choosing incorrect answers.
Question 30
It was pleasing that most candidates were able to interpret the heart pressure graph correctly.
Question 33
This question (on accommodation) caused problems. Even the more able candidates were evidently
guessing – they did not realise that most of the refraction occurs at the eye surface (and not at the lens).
Question 36
Some candidates did not believe that carbon compounds are excreted by living organisms. Presumably,
they forgot that carbon dioxide is a waste product of respiration.
Question 40
It was pleasing that most candidates could distinguish continuous and discontinuous variation.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
SCIENCE
Paper 5125/02
Theory (Physics)
Key Message
Candidates are advised to read each question carefully to ensure that their answers address the
question being asked.
General Comments
Most candidates showed evidence of being well-prepared and performed well. There was the
usual range of ability and it was pleasing to see that there were good answers to all questions.
Calculations were well done by many, although calculations involving changing units proved
difficult for some. Descriptions of experiments were clear and concise. Some candidates,
however, described the wrong experiment or gave general accounts rather than answering the
specific question that was asked.
Comments on Specific Questions
Section A
Question 1
This question required candidates to read the graph. The scale of the graph proved to be a
problem although most were able to state the length of the unloaded spring as between 6.3 cm and
6.5 cm to gain credit.
Only the most able could quote the extension of the spring when a weight of 4.6 N was attached.
The majority gave the length of the spring rather than how far it has extended. The correct answer
was 3.2 cm although a tolerance of 0.1 cm was allowed.
The graph proved to be difficult for all but the most able. These knew that beyond the limit of
proportionality, the length rises rapidly with added weight. The most common mistake was to
simply extend the existing line.
Question 2
(a)
Most candidates were able to calculate the mass as 110 g and so gained full credit. A
small minority worked out the mass correctly but incorrectly quoted it as 110 kg and a
small number did not give any unit.
(b)
Most candidates knew that they needed to multiply mass by gravitational field strength to
find the weight and so gained credit. The majority did not convert the mass to kilograms
and so did not get full credit.
(c)
The majority of candidates gained credit for stating that the gravitational field strength on
Earth is greater than on the Moon and so gained full credit.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
Question 3
(a)
A majority of candidates knew the general shape of the graph. Only the most able used
the information in the question to determine the key points to be plotted. Credit was
available for a line from zero to 40 m/s at 8 seconds. Further credit was awarded for a
horizontal line at 40 m/s running for 11 seconds and a straight line returning to 0 m/s in 6
seconds.
(b)
Almost all candidates gained credit for knowing that they needed to use K.E. = ½ mv2. A
sizeable minority used the wrong speed and there were a few who did not square the
speed.
(c)
Only the most able succeeded in working out the deceleration as -6.66 m/s2 and then
used F = ma to calculate the force as 3333 N to gain full credit. Most candidates gained
some credit for quoting F = ma or for working out the deceleration. A sizeable minority
incorrectly multiplied the mass by speed, distance or time to arrive at their answer.
Question 4
Credit was allowed for using the principle of moments and further credit was gained by calculating
the moment as 180 Nm. Most gained credit for doing one or both of these but only the most able
went on to gain full credit by calculating the correct answer of 60 N. A common mistake was to
multiply 15 N by 9 cm to find the moment.
Question 5
(a)
Almost all candidates knew that they need to use P.E. = mgh and so gained some credit
but few went on to calculate the correct answer as 180 J. The vast majority did not
convert the distance from centimetres into metres.
(b)
This question proved to be difficult for nearly all candidates. Almost all knew that they
need to divide work done by time to find the power but most were unable to work out that
the girl took 2 seconds for each step-up. Had they done so, they would have calculated
the correct answer of 90 W.
Question 6
(a)
Almost all candidates realised that conduction is the key process and most of these
gained credit for stating that energy is passed from particle to particle as a result of
increased vibration.
(b)
Only the most able minority gained credit for stating that black surfaces are good emitters
of radiation. Most candidates erroneously tried to explain why can A lost heat more
quickly by discussing increased absorption of radiation. Only a small number referred to
the effect of the water in can A being at a higher temperature.
Question 7
(a)
Almost all candidates identified the thermometer as a thermocouple and so gained full
credit. A small number incorrectly claimed that it was an industrial thermometer or a
bimetallic thermometer.
(b)
Most candidates gained full credit for realising that a liquid-in-glass thermometer would
not survive being at a temperature of 500 °C.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
Question 8
(a)
Most candidates gained credit for stating that sound waves are longitudinal whilst
electromagnetic waves are transverse, that sound cannot travel in a vacuum or that the
speeds were different. This gained them the credit that was available.
(b)
(i)
Most candidates gave the correct speed of electromagnetic waves in a vacuum. A
sizeable minority quoted 300 m/s or gave large but random values.
(ii)
Most candidates were able to use v = fλ to calculate an answer of 200 000 Hz and
so gained full credit. Those candidates who had given the wrong speed in (i) but
had used that speed correctly in (ii) gained full credit.
Question 9
This question proved to be difficult for all but the most able.
(a)
Although almost all candidates knew that they needed to divide p.d. by current to find the
resistance, few were able to determine the correct current in R1. This is found by
subtracting 0.8 A from the current from the battery. Most candidates used either 2.4 A or
3.2 A as the current in R1. Whilst these candidates gained some credit for trying to use
the correct formula, only those candidates who used a current of 1.6 A to calculate the
resistance as 7.5 Ω gained full credit.
(b)
Most candidates realised that the power in R2 is found by multiplying the p.d. by the
current in R2. A majority realised the current is 0.8 A and so calculated the correct answer
of 9.6 W. The main mistake was to use the wrong current.
(c)
The most straightforward way of calculating the combined resistance is by dividing the
battery voltage by the current in the battery i.e. dividing 12 V by 2.4 A. Only a very small
number of candidates realised this and tried, with varying degrees of success, to find the
resistance of each resistor and use 1/R = 1/R1 + 1/R2. Those who were able to do this
and find the correct answer of 5 Ω are to be congratulated on their persistence.
Question 10
(a)
The majority gained credit for realising that the number of neutrons is found by subtracting
the proton number from the nucleon number. The correct answer, obtained by most
candidates, is 146.
(b)
A nucleon number stated as being 237 and a proton number as 93 gained full credit. The
most common incorrect answers were 243 and 99.
(c)
The definition of half-life was known by most candidates. However, some answers lacked
the precision needed to gain credit.
Section B
Question 11
(a)
Many candidates gained most of the available credit for describing a suitable experimental
arrangement and detailing the readings that need to be taken. Weaker candidates
described an experiment involving reflection using mirrors. Others simply drew a diagram
of a ray being refracted without describing an experiment.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
(b)
This proved to be extremely difficult with few candidates drawing a ray diagram that
allowed them to find the focal length. Most candidates drew the formation of a real image,
missing the reference in the question to the image being upright and virtual.
Question 12
(a)
This question was very popular. Most candidates described a method of stroking but their
answers often lacked the detail needed to gain full credit. A small number are under the
impression that it is necessary merely to hold the magnet close to a steel bar in order to
make a magnet.
(b)
Most candidates gained credit for describing an arrangement that had the magnet inside a
coil carrying alternating credit. A small number thought that the current needs to pass
through the magnet. Only the most able gained further credit by giving appropriate detail
such as the need to remove the magnet to a great distance or to reduce the current to 0.
(c)
Surprisingly few candidates gained credit for stating that an electromagnet consists of a
coil carrying direct current wrapped around a soft iron core. Even fewer candidates stated
that magnetism is induced in the iron and steel in the scrap yard in such a way that
opposite poles result in attraction. There were many descriptions of domains in the iron
and steel but rarely did these descriptions lead to the explanation that was asked for.
Candidates do not gain credit for answering a different question to that which is asked.
Question 13
(a)
The majority of candidates knew the names of the wires connected in a three-pin plug and
most gained credit for knowing the colour of the insulation around them. A minority
confused the colours around the live wire and the neutral wire whilst a similar minority
confused the live wire with the earth wire – a potentially fatal misunderstanding.
(b)
This question was well-answered. Most candidates identified the earth wire as the one
that did not carry current in normal use. Most also gained further credit by showing that
they knew the function of the earth wire although most were content to state that it
prevented electric shocks. It was pleasing to see that a number knew that the function
was to cause a large current to flow to earth, thus blowing the fuse and switching off the
current, if the live wire touched exposed metal parts of the appliance.
(c)
Most candidates calculated the current as 8 A but not all went on to give a convincing
reason why the 5 A fuse is unsuitable. Only the most able stated that the fuse would melt
whenever the kettle is switched on. Many stated that the fuse would not blow even if a
fault caused the current to be too high which, of course, gained no credit.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
SCIENCE
Paper 5125/04
Theory (Biology)
Key Message
To perform well in Section A candidates need to follow the wording of the questions carefully.
Answers need to be clear and concise. Some elaboration is required to achieve full credit, but
excessively long answers should be avoided.
In Section B candidates have more freedom to express ideas. Answers should demonstrate their
knowledge and understanding of the subject in more detailed and involved aspects.
In both sections, candidates are expected to be able to interpret data presented in a variety of
formats. In Section B this is likely to involve candidates using their knowledge in less familiar
situations.
General comments
The number of candidates taking this component was very small. Some very good scripts were
seen, showing that these candidates had a good knowledge base and a sound grasp of the ideas
in the syllabus. Many others were able to give factual recall, but could not give interpretations or
explanations that were worthy of credit. Some wrote answers that were not of direct relevance to
the question asked or suggested they had misinterpreted the information given. For a number of
candidates, performance was weaker in Section B, where candidates were given less guidance in
how to frame their answers.
Comments on specific questions
Section A
Question 1
Most candidates showed good knowledge of blood components.
(a)
Many candidates correctly suggested carbon dioxide but fewer could find a second correct
answer.
(b)
Most candidates knew this to be a white blood cell, though some suggested a red blood
cell. Fewer could give a correct function.
(c)
Structures and functions of red blood cells were generally well known. A significant
number of candidates suggested that the biconcave shape was to allow travel through
narrow capillaries rather than to increase surface area for rapid diffusion of oxygen.
Question 2
Most candidates interpreted the data quite well.
(a)
More able candidates gave a clear description of a drug, but others had little idea of the
correct definition.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
(b)
(c)
(i)
Most candidates correctly worked out the risk to be five times greater.
(ii)
More able candidates realised that increase in risk is proportional to the percentage
of alcohol in blood, and that a decrease in the latter would give a decrease in the
former.
(i)
The majority of answers correctly referred to the slowing down of reactions or the
reduction of inhibitions and how these would affect driving.
(ii)
Most candidates gave two correct harmful effects. Some weaker candidates gave
harmful effects of smoking tobacco.
Question 3
The calculation proved to be a problem for many candidates.
(a)
(b)
(i)
Most candidates correctly suggested sun or sunlight. A common incorrect answer
was glucose.
(ii)
Only the more able performed this calculation correctly.
(i)
More able candidates gave the correct equation. Some weaker candidates gave the
equation for anaerobic respiration.
(ii)
Only the most able realised that heat is produced and lost to the atmosphere.
(iii)
Most candidates could give one correct way that energy is lost, but only the more
able could give two.
Question 4
Most candidates showed good graph plotting skills.
(a)
Most candidates plotted the results correctly but fewer could draw a curve of best fit.
(b)
Only the more able made sensible suggestions.
(c)
The majority of answers correctly included ideas of optimum temperature and denaturing
of the enzyme. Few also indicated that reaction rate, and therefore enzyme activity,
increases with increase in temperature (up to the optimum).
(d)
More able candidates gave the correct equation. A common error was to include lactic
acid.
Question 5
Most found interpretation of the diagram difficult.
(a)
Few candidates showed an understanding of the terms genotype and phenotype.
(b)
Most candidates could not translate the information in the diagram to give a sensible
answer to this question.
(c)
Most candidates had similar problems to question (b). Few sensible answers were seen.
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© 2011
General Certificate of Education Ordinary Level
5125 Science November 2011
Principal Examiner Report for Teachers
(d)
All but the weakest candidates filled in the diagram correctly to obtain a chance of 1 in 4.
A few used incorrect letters for the alleles, but still gained marks.
Section B
Question 6
Ideas about pollination had clearly been learned.
(a)
Many candidates had clearly learned this process and gained most of the marks. Others
gave vague rambling answers that gained little credit.
(b)
Weaker candidates confused seed dispersal with pollination. Others gave brief answers
that did not fully address the question. Few candidates gained more than one or two
marks.
Question 7
Few candidates had sensible ideas of how to conduct the investigation.
(a)
Most candidates knew that water is lost through stomata, but few could give any further
description of the process or explain its importance to plants.
(b)
Very few candidates gave a sensible answer. The idea that measurements were involved
occurred to only a few of the most able. Common incorrect answers involved leaving
plants in hot, dry conditions and observing that they wilt.
Question 8
This question allowed most candidates to gain marks.
(a)
Most candidates could relate energy intake to one or two of age, sex and activity, but only
the most able gave sensible answers for all three. Most realised that excessive intake
could lead to obesity, but few went further to suggest the long term effects this would
have.
(b)
More able candidates suggested two other nutrients. Some weaker candidates included
nutrients already given in the question. Adverse effects of nutrient deficiency were less
well known.
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© 2011