examinations council of eswatini egcse

EXAMINATIONS COUNCIL OF ESWATINI

EGCSE

EXAMINATION REPORT

FOR

PHYSICAL SCIENCE

YEAR

2019

EGCSE 2019 PHYSICAL SCIENCE EXAMINATION REPORT

2

Table of Contents

Subject Code: Name of Component: Page No:

6888 Physical Science P1 ………….. 3-9





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EGCSE PHYSICAL SCIENCE

Paper 6888/01

Short Answers

General Comments

This is a compulsory short answers type paper. The total number of candidates who sat for

this paper in the year 2019 was 11 739 which showed a decrease from the previous year. It

was generally a less challenging paper compared to last year’s paper. The marks ranged

from 1 to 36. The majority of candidates got marks in the range 15 to 20. Only a few

candidates managed to score above 30.

Some candidates failed to show understanding of Scientific concepts. For example, they

would state energy changes instead of explaining energy losses. Most candidates defined

galvanising instead of describing how galvanising prevents rusting. Some candidates lost

marks due to wrong use of symbols in equations. Some candidates also failed to state the

correct formulae, but instead they gave expressions.

Questions that proved to be easy for most candidates were Questions 1, 2 (a), 3, 10 and 16.

The most challenging questions were 8, 11, 12, 14 (b), 18 and 19.

Comments on Specific Questions

Question 1

This question was generally accessible to most candidates. Candidates were required to

choose the quantity measured using a spring balance from four given responses. Most

candidates were able to state the correct response which was D. The common wrong

response written was A.

Question 2

Candidates were given a diagram showing apparatus used to separate colourless amino

acids.

(a) This question was generally accessible. Candidates They were required to name the

method shown in the diagram. The expected correct response was chromatography.

A number of candidates wrote wrong spellings such as chromotography,

cromatography, chromatograph and chromatogram.


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(b) This question was generally accessible to most candidates. Candidates were required

to state the additional substance needed to identify the colourless amino acids. The

expected correct response was locating agent. The most common wrong responses

mentioned were; allocating agent, ethanol, iodine and biuret.

Question 3

This question was generally accessible to most candidates.

Candidates were required to calculate the average speed of a car that moves a distance of

100 minutes in 3 seconds. Some candidates lost a mark due to rounding off errors. The most

common wrong responses were 33 m/s and 33.0 m/s.

The most common wrong responses were; , , , , .

Question 4

This question was generally accessible to most candidates.

Candidates were asked to explain why the burning of hydrogen in air is a chemical change.

The common wrong responses were that water is irreversible, hydrogen is irreversible,

change of state from gas to liquid. Some of the candidates wrote wrong spellings e.g.

irrerveseable and irrevisible.

Question 5

This question was inaccessible to most candidates.

Candidates were given a speed-time graph of a heavy box falling from an aeroplane.

They were expected to describe the motion of the box between two points A and B labelled

on the graph. The common wrong responses were; non-uniform speed, speed is

accelerating, the motion is non-uniform, deceleration, motion is increasing, the aeroplane is

accelerating.

Question 6

Candidates were given structural formulae for four different organic compounds labelled

A – D.

They were required to choose an organic compound that;


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(a) Is in the same homologous series as hexane.

This part was generally accessible to most candidates as they were able to state the

correct response as A. The common wrong response written was D.

(b) Forms an ester.

This part was generally inaccessible to most candidates as they were not able to state

the correct response which was D. The common wrong response written was C.

(c) Is used in the manufacture of plastics.

This part was fairly accessible to most candidates as they were able to state the

correct response which was B. The common wrong response written was D.

Question 7

This question was inaccessible to most candidates.

Candidates were given a diagram of a three-pin plug with the pins facing them, labelled A

and B. They were required to name the labelled parts. The common wrong responses for the

part labelled A were: life, liver, earth, neutral, positive terminal, positive hole, positive socket

and the common wrong responses for the part labelled B were: earth, live, negative terminal,

negative hole, negative socket.

Question 8

This question was inaccessible to most candidates. Candidates were required to explain

using the kinetic particle theory why a liquid can flow but a solid cannot. The expected

response was that particles in a liquid can move from place to place while particles in a solid

vibrate in their fixed positions.

The following are wrong responses that were mentioned:

liquid particles are free to move while solid particles cannot move

when heated particles gain energy

or liquids can move from place while solids vibrate in their fixed positions

liquid particles are loosely packed while particles of a solid are closely packed


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Question 9

This question was inaccessible to most candidates. Candidates were required to state one

use of gamma rays. The expected response was that gamma rays kill cancer cells or

sterilise or detect cracks (flaws) in pipes or radiotherapy or preserve food or check weak

spots in welding. The common wrong responses were: burning cancer, TV, communication,

remote control, radio, to scan in hospital.

Question 10

Candidates were given a table showing some air pollutants and their sources.

They were required to complete the table by naming pollutant A whose source is car exhaust

and source B which emits carbon monoxide. The first part to the question was generally

accessible as most candidates were able to correctly name pollutant A as lead compounds

or oxides of nitrogen or carbon dioxide or unburned hydrocarbons or sulfur dioxide or carbon

monoxide. The common wrong responses mentioned were sulphur dioxide, sulfur oxide and

methane

The second part of the question was generally inaccessible. Very few candidates were able

to state the correct answer as incomplete combustion of carbon containing compounds

(fuels). The common wrong responses mentioned were: burning trees, incomplete

combustion of fuels, car engine

Question 11

This question was generally inaccessible to most candidates. Candidates were given a

diagram showing a student holding a pendulum bob against his nose. They were asked to

explain, in terms of energy changes, why the pendulum bob did not hit his nose when he

released it to swing freely away and back.

Most candidates stated energy conversions instead of energy losses which did not earn a

mark. The wrong responses mentioned were:

the pendulum bob loses energy

decreasing swing distance

the pendulum bob was not given enough force


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the bob loses gravitational potential energy to kinetic energy when it swings away

while when it swings back it loses kinetic energy to gravitational energy hence energy

is lost

Question 12

This question was generally inaccessible to most candidates. Candidates were required to

explain why brass (an alloy of copper and zinc) is stronger than copper or zinc. The

expected response was brass has different sized metal atoms which prevents layers of

atoms from sliding easily. Some candidates earned only one mark for stating that different

sized metal atoms could not slide or different sized metal atoms prevent layers of atoms

from sliding. The wrong responses mentioned were: different sized particles in brass prevent

particles from sliding, brass has properties of both metals.

Question 13

Candidates were given a diagram showing a ray of light incident to a glass block at an angle

of 60o.

(a) This part of the question was generally inaccessible to most candidates.

Candidates were required to draw and label the angle of incidence on the given

diagram.

Most candidates lost a mark for: 1) not drawing the normal correctly, 2) showing the

angle of incidence between the boundary and the incident ray and 3) wrongly

labelling the angle of incidence as j instead of i.

(b) This part of the question was generally inaccessible to most candidates.

Candidates were required to calculate the refractive index of the glass block given the

angle of refraction as 35.30.

The expected correct response was;

or


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Question 14

Candidates were given a diagram showing apparatus used to electroplate an iron nail with

copper metal.

(a) Candidates were required to name the cathode in the diagram. This part of the

question was generally accessible to most candidates as they were able to state the

expected correct answer.

Wrong responses mentioned were: copper metal strip, copper sulfate and

electroplating.

(b) Candidates were required to explain oxidation using the equation.

Cu Cu2+ + 2e-

This part of the question was generally inaccessible to most candidates. Some

candidates lost marks for not stating that a copper atom loses two electrons, instead

they would state that it is copper metal or copper element or copper ion that loses

electrons.

Question 15

Candidates were given a diagram showing Lunga carrying a log on his shoulder.

(a) This part of the question was inaccessible to most candidates.

Candidates were required to explain why the log balances horizontally on Lunga’s

shoulder after adjusting it.

The expected correct response was that clockwise moments equals to anticlockwise

moments (net torque is zero) or there was no net (resultant) force or the centre of

mass is directly above the pivot (shoulder).

Some of wrong responses mentioned were: 1) the centre of mass is near/ at/in the

shoulder, 2) forces on the left equals to forces on the right.

(b) This part of the question was accessible to most candidates.Candidates were

required to calculate the weight of the log, given that its mass was 30 kg.

Some candidates gave wrong units, for example 300 J, 300kg, 300 N/kg, resulting in

loss of a mark.


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Question 16

This question was one of the most accessible to candidates. Candidates were given a list of

words to choose from. They were requested to choose a substance that:

(a) Is a unit of matter. The correct expected response was atom. Common wrong

response was element.

(b) has a non-zero electrical charge. The correct expected response was ion.

Common wrong response was atom.

(c) is made from elements chemically bonded together. The correct expected response

was compound. Common wrong response was mixture.

Question 17

This question was inaccessible to most candidates. Candidates were given a diagram

showing a bar magnet. They were required to complete the diagram by drawing magnetic

field lines around the bar magnet. The common wrong responses were: field lines crossing,

dotted lines, wrong shape or pattern, wrong direction of arrows.

Question 18

This question was generally inaccessible to most candidates. Candidates were asked to

describe how galvanising a steel exhaust system of a car prevents it from rusting.

Common wrong responses were; zinc reacts with oxygen to form an oxide layer which

prevents rusting or defining galvanizing as oiling/painting with zinc or coating iron with

aluminium or mentioning sunlight as a cause for rusting.

Question 19

This question was the most inaccessible to candidates. Candidates were given a diagram

showing a Vernier callipers being used to measure the length of a cuboid. Candidates were

required to determine the length of the cuboid. Only a few candidates were able to determine

the correct length as 2.2 cm.


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Paper 6888/02

Structured Questions

General Comments

There was a decrease of about 600 candidates in the number of candidates who registered

for this component. In 2018, approximately 12500 candidates registered while in 2019

approximately 11900 candidates registered for this component. The reason for the drop in

the number of candidate is not certain but is assumed that more and more centres are opting

for Biology. The paper was marked out of a total of 80 marks. Generally, the paper was of

the same difficulty as last year. The scores ranged from 0 to 69. Although the highest score

is 2 marks less than the previous year, the performance by candidates was better than that

of 2018 as a noticeable number of candidates scored above 40 marks. The majority of the

candidates scored between 15 and 30 marks.

Use of correct symbols in formulae and equations was still a challenge even in 2019. Mixing

of symbols/letters and words in equations was common and it resulted in loss of marks.

Writing of expressions instead of equations was also common and it also led to loss of

marks. Another outstanding challenge was use of correct scientific terms, for example,

“combine” instead of the correct scientific term “react”.

Most candidates attempted all the questions. However, there were some candidates who did

not attempt some questions and part questions but it is not certain whether they did not

attempt these questions due to shortage of time or because they did not know what to write.

Questions that proved to be easy for most candidates were: 1(a), 2(a), 4(a) (i), 4(b), 8(b) (i)

and 9(a) as most candidates were able to score full marks from them. Questions that proved

to be difficult for most candidates were: 1(c), 3(c), 4(c), (d), 5(a) (iii), 5(b), 6(a), (b), (d), 8(a),

(c)(i), (ii), 9(b), (c), (d), 10(b), 11(b), (d) as most candidates failed to obtain marks from

these questions.


Question 1

In this question candidates were given a diagram of a liquid-in-glass thermometer with the

lower and upper fixed points marked and labelled.


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(a) This question was well answered.

Candidates were required to state the values of the lower and upper fixed points.

Most candidates were able to able to give the correct values of 0°C for the lower fixed

point and 100°C for the upper fixed point. A few candidates gave values without the

units and it resulted in loss of a mark. A common wrong response was 37°C for the

lower fixed point and 42°C for the upper fixed point.

(b) This question was poorly done. Most candidates failed to describe how the

thermometer can be calibrated using the lower and upper fixed points instead they

described how the lower and upper fixed points are determined. The expected

response was: measure the distance between the two fixed points and divide it into

100 equal divisions.

(c) (i) This question was also poorly done as most candidates failed to score a

mark from it. Candidates were required to describe how a larger bulb would

affect the sensitivity of the thermometer. A common wrong response was that

the thermometer would react fast to hot water.

(ii) This was another challenging question to most candidates as the correct

response of “divisions will be wider” was not common.

Candidates were supposed to suggest how the increase in the size of the bulb

would affect the scale of the thermometer. Common wrong responses were:

the scale increases and range will increase.

Question 2

This question was about the extraction of aluminium from its ore by electrolysis. A diagram

of the electrolytic cell was given.

(a) This was a well answered question as the correct response of bauxite as the main ore

of aluminium was common. The correct spelling was a challenge for some

candidates. Common wrong responses included aluminium bauxite, aluminium oxide

and haematite.

(c) This question was fairly done. Candidates were required to explain why aluminium

cannot be extracted by reduction with carbon. Most candidates were able to obtain at

least one mark out of the available two marks.


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A common wrong response mentioned was the use of word replace instead of

displace.

(d) This was a fairy done questions as most candidates were able to give at least one out

of the wanted two properties of aluminium that makes it suitable for the construction

of aircraft bodies. Some candidates did not answer the question but instead, gave

general properties of metals such as shiny, lustrous, ductile, good conductor of heat

and electricity. Other common wrong responses were: aluminium is less dense than

air, aluminium does not rust and aluminium has an oxide layer.

Question 3

This question was about the electromagnetic spectrum.

(a) This was a well done question. The majority of the candidates were able to give the

speed of the radio waves in vacuum as 3 x 108 m/s but a noticeable number of

candidates lost the mark for omitting the unit of speed. A common wrong response

was the speed of sound in air, 330 m/s.

(b) This question was fairly well done. Most candidates were able to recall the wave

equation, c = ƒ λ. A common error was the use of 0.2 km without converting to SI

units, 200 m. Another common wrong response was the use of the equation, f .

The symbol for wavelength, λ was a challenge for some candidates. Candidates lost a

mark for using uppercase F instead of ƒ.

(c) This was a poorly done question as most candidates were not able to explain why x-

rays are more harmful than radio waves. A few candidates were able to obtain one

mark out of the available two marks. Most candidates’ responses lacked comparison,

for example, candidates would give: “x-rays have a high frequency” instead of “x-rays

have a higher frequency than radio waves”. A common wrong response was: x-rays

travel at higher speed than radio waves.

The expected response was: x-rays have a much higher frequency than radio waves

or x-rays have a much shorter wavelength than radio waves and so they can cause

cancers and birth defects when they penetrate the skin.


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Question 4

This question was about the Periodic Table. Candidates were given a table showing the

number of protons, number of electrons and number of neutrons for three atoms.

(a) (i) This question was well done as the majority of the candidates were able

identify atom X, using the Periodic Table, as oxygen.

(ii) This was a fairly done question as most candidates were able to score at least

one mark out of the available two marks. Candidates were required to explain

why Z is an isotope of X. Candidates lost a mark for giving the definition of an

isotope without any reference to the information in the table.

(b) This was a well done question. Most candidates were able to draw the “dot-and-

cross” diagram for the covalent compound formed when hydrogen reacts with X

(oxygen). A common wrong response was: showing more than two electrons being

shared between the atoms.

(c) This was one of the most challenging questions for most candidates. Most candidates

failed to explain the difference in the melting points of the ionic compound, Na2X

(Na2O), and the covalent compound, H2X (H2O). Most candidates’ responses lacked

comparison between the ionic compound and the covalent compound. Common

wrong responses included reference to boiling point. Use of ‘atoms’ instead of ‘ions’ in

Na2X and use of ‘atoms’ instead of ‘molecules’ in H2X resulted in loss of marks.

The expected response was: Na2X has a higher melting point than H2X because Na2X

has strong forces of attraction between the ions while H2X has weak Van der Waals

forces between the molecules.

(d) This question was poorly done as most candidates were unable to score more than

one mark out of the available three marks.

Candidates were required to state the colour and oxidation state of sodium and

copper compounds. Some candidates were able to give the colour of copper but

failed to give the oxidation states. Common wrong colour of copper were: brown,

reddish brown and grey. Common wrong oxidation states were: Na+ and Cu2+. Other

common wrong responses for the oxidation states were: 1 electron and 2 electrons.


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Question 5

This question was on energy and acceleration due to gravity.

(a) (i) This question was fairly well done. Most candidates were able to recall and

use the formula K.E. = ½ mv2. Some candidates did not convert the 200 g to

0.2 kg before substituting into the formula and they lost a mark. Candidates

also lost a mark for writing an expression ½mv2 instead of an equation.

Omission of units in the answer also resulted to candidates losing a mark.

The expected response was: K.E. = ½ mv2 = ½ x 0.2 x 32 = 0.9 J

(ii) This was another fairly well done question as most candidates were able to

calculate the maximum height reached by the ball by using the law of

conservation of energy. Candidates lost marks for using wrong symbols or

letters in the formula such as EP = mgh instead of P.E. = mgh. A common

wrong formula was: K.E. = mgh.

A few candidates were able to recall the formula P.E. = mgh but failed to make

h the subject of the formula.

(iii) This part of the question was poorly done as most candidates could not state

no air resistance or no energy is lost as the assumption made when calculating

the maximum height reached in (a) (ii). The most common wrong response

was: potential energy = kinetic energy.

(b) This was another poorly done question as very few candidates scored a mark. A few

candidates were able to obtain a mark for stating that marble C will reach the same

height as B but could not explain why.

Common wrong responses were:

- marble C will reach a higher height because of its smaller mass.

- they reach the same height because they travel at the same speed of 3 m/s.

The expected response was: marble C will reach the same height as B because mass

has no effect on the acceleration due to gravity.

Question 6

In this question, candidates were given a flow diagram showing methods for preparing two

salts, copper(II) sulfate and barium sulfate. In general, the whole question was poorly done.


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(a) This question was poorly done. The majority of the candidates failed to identify oxide

D as copper (II) oxide. Common wrong responses were: copper oxide, metal oxide

and basic oxide.

(b) This question was also poorly done as most candidates failed to name the method

used to prepare barium sulfate in the flow diagram. Common wrong responses were:

filtration, neutralisation and displacement.

(c) This was a fairly well done question as most candidates were able to identify

substance E in the flow diagram as water. A common wrong response was hydrogen.

Oxygen was also mentioned by some centres.

(d) This was a fairly well done question. Most candidates were able to classify sulfur

oxide as an acidic oxide but failed to give a correct reason for the answer. Common

wrong classifications were: amphoteric oxide and neutral oxide and common wrong

reasons were: because it is a non-metal oxide and because it causes aid rain.

Question 7

This question was on electricity. Candidates were given a circuit diagram consisting of 3

resistors and 3 ammeters and a 2 V power source.

(a) This question was fairly done as most candidates were able state the potential

difference across R3 as 2 V.

(b) (i) This part question was also fairly done as most candidates were able to

recall and use the formula I = V/R to get the correct response of 0.33 A. A

common wrong formula was I = R/V.

(ii) A fairly well done question. The correct calculation of Q = It = 0.33 x 10 s =

3.3 C was common. A common wrong formula was: Q = VIt. Candidates lost a

mark for using wrong symbols and/or letters such as C for charge instead of Q

and T for time instead of t.


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(iii) Another fairly well done question. Most candidates were able to calculate the

combined resistance of the two resistors, R1 and R2. Common wrong

responses were RT = R1 + R2 and RT =

(iv) This was a poorly done question. Only a minority of the candidates were able

to recall that the main current in a parallel circuit is the sum of the currents in

the branches. Most candidates tried to calculate the reading of ammeter A2

using Ohm’s law, V = IR and they lost the mark.

The expected response was: 1.7 + 0.33 = 2.03 A

Question 8

This question was on stoichiometry. Candidates were given that calcium carbonate breaks

down to form calcium oxide and carbon dioxide when heated.

(a) This question was poorly done. Most candidates could not name the type of

reaction involved when calcium carbonate is heated.

Common wrong responses included: chemical reaction, endothermic reaction and

combustion.

(b) In this part of the question candidates were given the chemical equation for the

breakdown of calcium carbonate to form calcium oxide and carbon dioxide when

heated in a kiln.

CaCO3 → CaO + CO2

(i) This part question was very well done. Most candidates were able to

calculate the relative formula mass, RFM, of calcium carbonate, CaCO3.

(ii) A fairly well done question. Candidates were required to calculate the number

of moles of calcium oxide that are produced when 20 g of calcium carbonate is

heated in the kiln. Most candidates were able to score the first two marks from

= 0.2 moles of CaCO3. They were then supposed to use the

ratio of moles, CaCO3 : CaO = 1:1 to get the number of moles of CaO = 0.2

moles. The last mark was very scarce.


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(iii) This part of the question was poorly done. Most candidates failed to use the

mole ratio to calculate the number of moles of carbon dioxide produced when

20 g of calcium carbonate is heated in the kiln. The common wrong response

was

n = 20/44 = 0.4545 moles.

The expected response was: ratio of moles CaCO3 : CO2

1: 1

= 0.2 moles

(iv) This question was also fairly well done as most candidates were able to recall

and use the formula V =n Vm. A common wrong response was 24 dm3 x 20 g.

(c) (i) This was a poorly done question. Most candidates failed to describe the use

of calcium carbonate in the manufacture of glass. A common wrong

response was that calcium carbonate makes the glass stronger.

The expected response was: limestone heated with sand and sodium

carbonate

(ii) This part of the question was fairly done. Most candidates were able to score

at most one mark out of the available two marks. Candidates were expected to

describe the use of calcium carbonate in the extraction of iron. Naming of

impurities as silicon oxide instead of silicon (IV) oxide resulted in a loss of a

mark.

Question 9

This question was on transformers. Candidates were given a schematic diagram of a

transformer with a power input of 21 MW, primary voltage of 25 000 V and secondary voltage

of 11 500 V.

(a) This was a well done question. Candidates were required to state the type of

transformer that was shown. The expected answer of ‘step-up transformer’ was very

common. A common wrong response was: electric transformer.


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(b) This was a challenging question to most candidates. Candidates were required to

state the purpose of high voltage transmission of electricity.

A common wrong response was: to reduce electricity loss over long distances.

Candidates also lost a mark for stating that high voltage transmission avoids or

prevents energy loss because it does not prevent it but rather, it minimizes or reduces

the energy loss.

(c) This question proved to be a challenge to most candidates. Candidates were required

to describe how the transformer converts one input value of voltage to a different

output value. Some candidates who had the idea lost some marks for not stating that

the current in the primary coil must be alternating current, the magnetic field produced

in the soft iron core is a changing or alternating magnetic field and that the induced

emf/ current in the secondary coil is alternating current.

Another common wrong response was: alternating magnetic field is induced in the

secondary coil.

The expected response was: alternating current in the primary coil induces a

changing magnetic field in the soft iron core which then induces an alternating current

in the secondary coil which has a different number of turns compared to the primary

coil.

(d) This was another poorly done question. Candidates were required to calculate the

output current in the transformer. Most candidates used P = VI instead of Vp Ip = Vs Is

and they lost a mark. A common challenge to most candidates was the conversion of

21 MW into 21 000 000 W before substituting in the formula. Some candidates could

not realise that the 21 MW represented the input power, Vp Ip.

The expected response was: Vp Ip = Vs Is

21 000 000 = 115 000 Is

Is = 21 000 000 / 115 000

Is = 182.6 A

Question 10

In this question candidates were given a figure that showed processes used to manufacture

ethanol.


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(a) This was a fairly done question. The expected response of enzyme as the constituent

in yeast that will convert glucose to ethanol was common. A common wrong response

was naming the enzyme as amylase instead of zymase.

(b) This question was poorly done. Most candidates could not name process F, where

steam is added to ethene. Common wrong responses were: dehydration, hydrolysis

and addition of steam.

(c) This question was fairly done. The majority of the candidates were able to draw the

structure of the fourth member of the alcohol homologous series.

The expected structure was:

(d) This was another fairly done question. Most candidates were able to obtain at least

one mark out of the available two. Candidates were required to describe the formation

of ethanoic acid using atmospheric oxygen. A common misconception was that the

bacteria oxidises ethanol or the bacteria reacts with the ethanol.

Question 11

(a) This was a fairly done question. Candidates were required to complete an equation

for the beta decay of radon – 222. Most candidates were able to score at least one

mark. Common wrong responses were and .

Candidates lost marks for using lower or upper cases such as and

(b) This question proved very challenging to most candidates. Candidates were required

to explain why β particles are deflected when they pass through a magnetic field.

Most candidates confused a magnetic field with an electric field.

Common wrong responses included: beta particles have a negative charge so they

are attracted towards the north-pole and beta particles are less massive so they are

easily deflected.

C C C C O H

H

H

H

H

H

H

H

H

H


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The expected response was: a magnetic field exists around the beta particles. The

magnetic field of the beta particles interacts with the magnetic field of the magnets.

(c) This was a fairly done question as the majority of the candidates were able to state

that using thick lead containers was one safe method of storing the radon-222.

Common wrong responses included: store underground, store in aluminium

containers, store in sealed containers and store under paraffin or oil.

(d) This question was also challenging to most candidates. Candidates were required to

calculate the amount of sample remaining after 16 days if radon has a half-life of

4 days and a 30 g sample is left to decay for 16 days. The common wrong response

was 16/4 = 4 days. Candidates also lost a mark for omission of the unit of mass, g, in

their answer.

The expected response was: at start → 30 g

after 4 days → 15 g

after 8 days → 7.5 g

after 12 days → 3.75 g

after 16 days →1.875 g


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Paper 6888/03

Practical Test

General Comments

The Practical Test generally test candidates’ science practical skills, objective C of the

syllabus. In this year’s paper a range of science skills were tested including carrying out a

procedure, making qualitative and quantitative observations, interpretation of data and

designing a practical activity.

The number of entries in this paper declined when compared to 2018. The paper was quite

discriminating as there was a range of marks obtained by candidates from four to more than

thirty marks out of the forty marks on offer. The time allocated the paper seemed to be

adequate as most candidates were able to finish the paper.

The candidates displayed a general weakness in writing observations, carrying out a

practical activity and writing a practical procedure. There was a noticeable increase in writing

observations like reddish, whitish colour instead of red or white colour. As a result,

candidates lost marks.


Question 1

(a) Candidates were provided with two strips of metals R and S and iron nails. Metal R

was magnesium and S was copper. Candidates were required to describe the

physical appearance of metals R and S.

This part of the question was accessible to most candidates.

Some most common wrong responses included malleable/ ductile/ less dense/ hard

and soft. Other candidates lost the mark as they described the appearance of the

metals as brownish/greyish/reddish.

The expected response was,

R, grey/shinny/silver

S, red-brown/shinny


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(b) (i) Candidates had to react metal R and an iron nail with copper(II) sulfate

solution and recorded their observations

This part of the question was challenging to candidates as quite a number of

them could not differentiate between an observation and conclusion.

The most common wrong response was a gas is produced.

The expected observations were:

R, red-brown solid formed on the surface of R/blue solution fades in

colour/bubbles formed

Iron nail, red-brown solid formed on the surface of the nail/deposits on the nail/

blue solution fades in colour/blue solution turns green in colour

(ii) Candidates were required to react metals R, S and the iron nail with dilute

hydrochloric acid. Candidates were then required to record their observations.

This part of the question was accessible to those candidates who could

differentiate between an observation and a conclusion.

A number of candidates wrote wrong spelling of bubbles such as buble,

boobles and bobbles.

(iii) Candidates were required to arrange the three metals in order of reactivity

starting with the most reactive.

This part of the question was accessible to most candidates as they earned

the two marks on offer.

The expected response was R iron nail S

(c) (i) In this part of the question candidates were asked to burn a piece of metal R

using a strong Bunsen burner flame and record their observations.

This part of the question was accessible to quite a number of candidates.

Some common wrong responses included metal R is flammable, a basic oxide

is formed, white precipitate is formed.


23

The expected responses were R burns with a brilliant blinding flame

and a white solid/white ash.

(ii) In this part of the question candidates had to dissolve the white solid formed

in (c)(i) in water and test pH of the solution formed.

This question was challenging to candidates. Some candidates gave a pH

value greater than 7 but concluded that the solution formed was acidic while

some gave a pH less than 7 and concluded that the solution formed was

alkaline.

The expected response was a pH from 8-14 and a conclusion of alkaline.

(iii) Candidates were then required to described how they tested the pH of the

solution formed in (c)(i).

This question was challenging to most candidates as they failed to describe

the experimental procedure they carried out in testing the pH of the solution

formed.

Quite a number of candidates showed a lack of familiarity with the Universal

indicator paper. They referred to it as the yellow litmus paper and this resulted

to them losing one mark.

The expected response was drop on to Universal indicator paper and match

colour formed on pH chart.

(d) Candidates were required to react some of the solution formed in (c)(ii) with

hydrochloric acid. Then they evaporated the resultant solution using a Bunsen burner

flame.

(i) Candidates were required to record the colour of the substance formed after

caring out the evaporation.

This part of the question was accessible to most candidates as they gave the

expected response of white.

Some common wrong responses included whitish/yellowish/transparent.


24

(ii) Candidates were required to state the type of reaction that took place when

reacting the solution with hydrochloric acid.

This part of the question was challenging to candidates. Quite a number of

candidates lost the mark as they gave wrong responses such as exothermic

reaction/crystallisation reaction/basic reaction.

The expected response was neutralisation reaction.

(e) In this part of the question candidates were required to react the remaining solution

formed in (c)(i) with a few drops of aqueous sodium hydroxide.

(i) Candidates were required to record their observations. This part of the

question was accessible to candidates.

Some common wrong responses included white emulsion/cloudy

solution/colourless precipitate.

The expected response was a white precipitate is formed.

(ii) Candidates were required to draw the apparatus they could use to separate

the substance formed in (e)(i) if it were carried out on a larger scale in a school

laboratory.

Some common wrong responses included apparatus for paper

chromatography/distillation apparatus/sublimation apparatus.

The expected response was the filtration apparatus with filter paper, filter

funnel and collecting vessel labelled.

(f) In this part of the question candidates were required to state one precaution to be

taken when handling acids.

This question was the most accessible to candidates.

Some common wrong responses included wear plastic gloves/do not inhale/do not

touch with bare hands. The spelling of goggles was challenging to candidates. They

wrote google instead.

The expected response was avoiding skin contact by wearing gloves/laboratory

coats/goggles.


25

Question 2

In this question candidates investigated some factors that affect the strength of an

electromagnet.

(a) (i) A circuit containing an electromagnet with 30 turns was set up for candidates.

Candidates had to close the switch and bring one paper clip to one end of the

electromagnet. Then they had to bring a permanent magnet with its North Pole

closer to the end of the paper clip but not touching it. Candidates were then

required to state their observations.

This part of the question was accessible to candidates. Some candidates tried

to explain attraction/repulsion but ended up contradicting themselves. They

gave wrong responses such as the paper clip moved closer to the permanent

magnet and closer to the electromagnet.

The expected response was either repel/attract.

(ii) In this part of the question candidates were required to bring the south pole of

the permanent magnet closer to the paper clip but not touching. Then

candidates had to record their observations.

This question was accessible to candidates. Some wrong responses included

paper clip attracted to electromagnet and to permanent magnet.

The expected response attract/ repel.

(iii) Candidates had to deduce the polarity of the end of the electromagnet based

on their observations in (a)(i) and (a)(ii).

This part of the question was very challenging to candidates. The term

polarity seemed foreign to candidates some candidates left this question

unanswered. The candidates who attempted the question only gave the

polarity the polarity of the electromagnet without showing the polarity of the

paper clip.

The expected response was the end of the electromagnet was North, as end

of paper clip attached to electromagnet is south pole/south, as end of paper

clip attached to electromagnet is North pole.


26

(b) (i) Candidates had to bring another paper clip to one end of the first paper clip

such that it touches it. Then candidates had to record and explain their

observation.

This question was accessible to candidates. Some candidates earned only

one mark as they had challenges explaining their observations. Some of the

wrong explanations included electromagnet is weak/ more turns should be

added.

The expected response was:

observation- the second paper clip is attracted to the first one

explanation- the first paper clip is magnetised by the electromagnet

(ii) In this part of the question candidates were required to keep adding paper clips

and record and explain their observations.

This question was challenging to candidates. Candidates had challenges

stating their observations such that evidence of maximum number of clips

attracted was not given and the concept of induced magnetism becoming

weaker further away from the electromagnet was very rare. Some wrong

responses included attraction/ paper clips fall/ weak electromagnet.

The expected response was

observation - the last paper clip is no longer attracted/ stated maximum

number of clips attracted

explanation - further away from electromagnet, induced magnetism is

weakened.

(iii) Candidates were required to open the switch and state and explain their

observations.

This question was accessible to candidates. Some candidates lost one mark

as they referred to magnetism lost by clips and not magnetism lost by core.


27

The expected response was –

observation - paper clips will drop

explanation - electromagnet lost magnetism.

(c) This question required candidates to add one more cell in the circuit and repeat

the procedure in (b)(i) and (b)(ii). Then candidates had to state and explain

the effect of increasing the number of cells.

This question was accessible to candidates as they were able to make the expected

observation that increasing the number of cells increases the number of paper clips

attracted.

Some candidates lost one mark as they gave incomplete responses.

The expected response was increasing the number of cells increases the number of

paper clips attracted as the strength of the electromagnet also increases

(d) Candidates were required to replace the coil with 30 turns with a coil with 60 turns

and repeat the procedure in (b)(i) and (b)(ii). Then candidates had to compare the

results with those obtained in (c).

Some candidates did not show any comparison with (c) which resulted in the loss of

marks. Some common wrong response included paper clips attracted very fast/

paper clips attracted strongly.

The expected response was increasing the number of turns increases the number of

paper clips attracted because more turns increases the strength of the magnet

(e) Candidates were required to make one suggestion of how the accuracy of the

experiment could be improved.

This part of the question was challenging to candidates as they stated what has

already been done in the experiment like increasing number of turns.

Some common wrong responses included use same cells/ add more turns/ use

electricity.

The expected response was use new cells for each measurement/ switch off

between measurements/use variable power supply/repeat experiment and average

result/use soft iron core.


28

(f) Candidates were required to design an experiment to show the magnetic field lines of

an electromagnet.

This part of the question was challenging to candidates. Some common wrong

responses included sprinkling electromagnet with iron fillings and more fillings

attracted to poles/bring permanent magnet to ends of electromagnet to identify

poles.

The expected response was place a piece of paper on electromagnet sprinkle iron

fillings over paper and gently tap the piece of paper to form magnetic field lines/

place piece of paper on or below electromagnet then place plotting compass on

piece of paper and mark direction to which the compass is pointing.


29


Paper 6888/04

Alternative to Practical Test

General Comments

The Alternative to Practical Paper endeavours to assess candidates on Assessment

Objective C of the EGCSE syllabus. This Objective ideally aims at ensuring that scientific

skills and values as well as attitudes, clearly articulated in the syllabus documents, are

indeed instilled and inculcated in the candidates to give them a competitive edge in future

scientific undertakings. This is the rationale for this paper.

The paper accounts for a 20% weighting to the overall final mark of the candidates as per

the syllabus dictates. It is marked out of 40 and consists of one Chemistry and one Physics

question. The number of entries was relatively similar to the previous year at around 8300.

The paper assessed a range of scientific skills with the ability to make observations and

make inferences from the observations being paramount; and the ability to distinguish

between these two skills by responding to posed questions in a relevant manner well

adjudicated. Candidates were also assessed on the rationale for using scientific procedure

and equipment, safety procedures in science, decision making in scientific experimentation,

the correct use of scientific equipment as well as their aptitude in scientific literacy. They

were also expected to demonstrate adeptness in evaluating scientific procedure and suggest

improvements. The paper attempted differentiated assessment in allowing candidates who

may be challenged at giving written responses to present their responses in the form of

drawings.

The questions in the paper were largely valid since most candidates seemed to understand

them and attempted them in the same manner testament to the lack of ambiguity in the

questions. The time allocated to the paper seemed adequate as there was no evidence of

candidates that failed to finish the paper. It was the considered view of the Examiners that

the questions or sub-questions that were left unanswered by some candidates were due to

challenges that those questions posed to the candidates as opposed to time constraints.


30

The paper was fairly challenging to the candidates. There were quite a number of candidates

who obtained less than 50% of the marks on offer with a significant number getting zero

marks. However, it proved to be fairly discriminating as a number of candidates obtained

marks on the top end of the performance continuum with the highest mark being an 83% and

a substantial number of candidates obtaining more than 75%. The main challenge for the

candidates was that most of the questions were qualitative, demanding explanations, written

descriptions and or statements from the candidates. Language proficiency or lack thereof

then becomes an inherent challenge to most candidates. The Examiners had a tough time

‘gleaning’ the science from the language expressions as per the guidance and provisions

from the Cambridge guidelines.


Question 1

(a) The question required candidates to write the physical appearance of the metals

magnesium and copper.

The question proved to be quite challenging to the candidates. They failed to

appreciate that it was the appearance that was expected not general physical

properties of the metals. They were giving physical properties such as hardness,

ductility, malleability, high melting points and electrical conductivity which are

general properties of metals but have nothing to do with the appearance of

copper or magnesium. Some candidates who realised that colour was part of

appearance then spoiled their responses by the suffix -ish, that is, greyish or

brownish which incurred penalties from the Examiners.

The candidates were expected to mention that magnesium was grey, silver or

shinny.The expected response for copper metal was that it is brown or shinny.

Red-brown was accepted as the correct response for copper.

(b) (i) Candidates were expected to state observations when the iron nail and

magnesium were separately placed in a copper(II) sulfate solution.

This question was fairly well attempted by the candidates. However, a number

of them wrote conclusions such as a fast reaction in magnesium or slow

reaction or no reaction in the iron nail instead of the observations required of


31

them. Some would write responses such as that the iron nail got electroplated,

clearly manifesting the confusion of the concepts of the displacement of metals

and electrolysis.

Expected responses were:

Magnesium- brown solid formed. Effervescence or the evolution of

bubbles were accepted as alternative responses

Iron nail – brown solid coating the nail.

Credit was given to candidates who made reference to the correct colour change

of the blue copper(II) sulfate solution, to colourless in magnesium and to green

in the iron nail.

(ii) Candidates were expected to state their observations in three test-tubes

containing hydrochloric acid with the metals magnesium, copper and an

iron nail, respectively.

This question was also fairly well attempted by the candidates. Even here, most

candidates lost marks by writing conclusions instead of observations. Some

repeated their incorrect responses from (b)(i) while others would write

conclusions about the reactivity of the metals with incorrect responses such as a

vigorous or rapid reaction quite common. Some mentioned the formation of

coloured precipitates which was incorrect.

Expected responses were that bubbles were evolved in the magnesium

ribbon and the iron nail test-tubes while there was no change in the test-tube

containing copper. Candidates who gave their observations in terms of

bubbles in the copper test-tube were not penalised.

(iii) Candidates were expected to arrange the metals magnesium, copper and iron

in the correct order of reactivity.

The question was well quite accessible to the candidates. Most of them were

able to arrange the metals in the correct order with magnesium being the most

reactive and copper the least reactive. Even those who lost some marks, were

able to give magnesium as the most reactive and hence obtained the first mark.


32

A reasonable number of candidates wrote magnesium as the most reactive,

leaving out iron in the second line and on the third line wrote copper. Examiners

made an effort not to punish such candidates on the assumption that they were

aware of the reaction order. Some candidates wrote the correct order starting

with magnesium on the first line and then wrote on the third line starting with

copper. They were not penalised if both orders were correct and there were no

contradictions.

Expected response was: magnesium, iron, copper which earned two marks.

(c) (i) The question required candidates to write their observation when magnesium

undergoes combustion.

Most of the candidates struggled with this question. They were neither able to

give the characteristic colour of the flame produced when magnesium burns nor

the colour of the residual powder. A significant number of candidates decided to

name the product formed as magnesium oxide which was unacceptable as this

was not an observation. Some gave purple flame and white precipitate as

though the white solid was formed in solution; while some wrote a bright flame

which also led to the hemorrhaging of the marks on offer since brightness is

relative. A number of candidates referred to the white solid as a precipitate which

was also quite unacceptable since the solid was not formed in solution.

The expected response was a brilliant flame, white flame, blinding flame or very

bright flame was observed.

They had to earn the second mark by stating that white ash or a white solid

was also formed.

(ii) Candidates were required to describe how they would test the pH of a solution

formed when magnesium oxide was dissolved in water.

The question proved to be quite challenging to the candidates. A huge number of

candidates gave litmus paper as the indicator that is used to determine the pH

value. Some candidates were aware of the correct indicator to use but then wrote

‘use universal indicator’ which failed to reach the threshold of the description

demand of the question and lost the first mark. This was the main weakness of the


33

candidates, that is, the failure to correctly respond to the command word

‘describe’. Other candidates did not give the specific name of the indicator but

they remembered that an indicator was supposed to be used. A few gave

indicators such as phenolphthalein which do not give the specific pH values and

also lost the marks on offer.

The expected response was: dip universal indicator paper in the solution or pour

a few drops of universal indicator into the solution to earn the first mark; and

then match the colour formed on the indicator against the pH chart for the

second mark.

(iii) The candidates were expected to suggest the pH value of the solution

formed when magnesium oxide was dissolved in water.

This question was well attempted probably owing to the relatively big range

of permissible pH values tolerated by the Examiners. Candidates were able

to work out that magnesium oxide was a basic oxide and would dissolve to

form an alkaline solution, so it had a pH range of 8 to 14. Some candidates

elected to write decimals and ignored the syllabus directive that the pH

values should only be whole numbers, even though they did not incur any

penalties for this. A few candidates were giving pH value as ‘acidic or

alkaline’ while some gave pH values less than 7.

The expected pH values were to range from 8 to 14.

(iv) The question demanded candidates to classify the oxide that had been

formed in the combustion of magnesium.

The question was fairly well attempted by the candidates. The most common

incorrect response advanced by the candidates was that the oxide was

magnesium oxide which is not a class of oxides but rather the name of the oxide.

Some would say it is an alkali oxide which was unacceptable because this implies

that the oxide was soluble which is incorrect. Some were giving the name metal

oxide, carbon dioxide, carbon monoxide, to name but a few. Some mentioned that


34

the oxide was a base oxide which was tolerated by the Examiners since metallic

oxides are bases.

The expected response was that the oxide was a basic oxide.

(d) In the question, candidates were expected to describe how crystals could be

obtained from a neutral solution formed when magnesium oxide reacts with dilute

hydrochloric acid.

The question was fairly well attempted by the candidates. Candidates were

expected to give an outline of all the steps involved in getting crystals from the

solution. They were supposed to transfer the solution into an appropriate vessel

such as an evaporating dish and then describe the correct method for obtaining

the crystals. A number of candidates lost the first mark by omitting the part of

transferring the solution to an appropriate vessel (i.e. evaporating dish). Some

who remembered that a container was used would say the solution should be

transferred to a petri-dish and also lost the mark since such a container was not

appropriate.

Then, on obtaining the crystals, candidates seemed to confuse the process of

evaporation with that of crystallisation. When using the crystallisation method, most

candidates omitted that the solution must be heated until it gets saturated or

concentrated which made them lose the second mark. In the case of evaporation,

candidates would say the solution evaporates when heated instead of mentioning the

solvent that evaporates when heat is applied. Some would not mention the role of the

addition of heat in both processes and got penalised. Other candidates used phrases

such as ’boil the solution’ or ‘burn the solution’ instead of saying heat the solution.

Expected response:

Evaporation: pour solution into an evaporating dish for the first mark, then heat the

solution to evaporate the water for the second mark

Crystallisation: heat to concentrate or saturate the solution earned the first

mark, then cool the solution to crystallise earned the second mark.


35

(e) The question required candidates to draw the apparatus that could be used to

separate a precipitate from a solution.

This was generally not well done by the candidates. A significant number of

candidates drew the distillation apparatus or apparatus for sublimation. Those that

realised they had to draw the filtration apparatus, somehow elected to draw

incomplete set-ups by either omitting the filter paper or the filter funnel and lost

the first mark. Some candidates drew unassembled apparatus while some did not

label their apparatus. Some of those who labelled their apparatus would label the

filter funnel as the separating funnel which was quite unacceptable; yet some

would label the filtrate as residue and vice versa. Other candidate labelled the

filtrate as distillate. Others drew the apparatus of the method they described in (d)

which also led to the loss of all the marks.

The expected response was that the candidates had to draw a filter paper, filter funnel

and a collecting vessel to earn the first mark; they then had to correctly assemble this

apparatus to earn the second mark and correctly label two pieces of equipment on the

correctly assembled structure to earn the third mark.

(f) The question expected candidates to state one precaution when handling acids.

The question was quite accessible to the candidates. Most of them were able to give

the correct response as wearing gloves/ lab coat/ goggles or any other relevant item

to avoid skin contact. However, others wrote ‘cloves’ instead of ‘gloves’ and they lost

the mark, while others wrote ‘googgles’ for ‘goggles’.

Common wrong answers included the following: do not touch acids with your

hands; acids must not touch your clothes; wear protective clothing; wear plastic

gloves. Some generally referred to avoidance of the tasting of acids in the

laboratory which did not earn any mark since this is a general laboratory rule for

all chemicals.

Question 2

(a) (i) Candidates had to state the observation made when an electromagnet was

brought to paper clips with the switch closed in the circuit.


36

The question was quite accessible to the candidates. Most candidates were able

to correctly state that the paper clip was attracted to the iron core. A few

candidates gave a conclusion instead of an observation as their response, that

is, the paper clip was magnetised, thus mixing important Scientific skills, hence

lost the mark.

Some candidates thought that the current flowing through the solenoid also flows

through the core hence through the paper clip, yet the copper wire is insulated,

which is wrong Science and got the just penalty.

The expected response was that the paper clip was attracted to the iron core.

Alternative description of same was accepted.

(ii) This question required candidates to deduce and label the polarity of a paper

clip and an electromagnet when a paper clip, attached to an electromagnet,

repelled a permanent magnet brought close to it.

The question was fairly well attempted by the candidates as most were able to

label the correct polarity on the paper clip, with the North pole on the end of the

paper clip next to the North pole of the permanent magnet; and the South pole on

the end of the paper clip next to the end of the electromagnet. These candidates

displayed the understanding of the concept of induced magnetism. However,

some candidates seemed not to understand the term polarity as they would draw

magnetic field lines between the clip and the permanent magnet instead of the

poles. Some would choose to draw only one North pole on the clip instead of the

two poles and got penalised since it was not clear if they understood the position

of the South pole. Some would show the polarity of the paper clip only and lost

the second mark for the polarity of the electromagnet. Some candidates seemed

to confuse magnetism and charges (electrostatics) and would show positive and

negative charges on the ends of the magnets and on the paper clip, thus losing

both marks.

The expected responses were the correct polarity of the paper clip with the North

pole adjacent to the North pole of the permanent magnet which earned the first

mark. The second mark was earned by showing the correct polarity of the

electromagnet with the South pole on the extreme left of the electromagnet.


37

(b) (i) Candidates had to explain why a second paper clip was attracted to the first

paper clip that was already attached to the electromagnet.

This question was well done as most candidates were able to state that the

second paper clip was attracted because the first paper clip had been

magnetised. Some candidates lost the mark by confusing magnetism and

electrostatics even here by stating that the first and second paper clips had

opposite charges. Some thought that current had been induced in the first paper

clip instead of magnetism, which was untrue and did not earn the mark.

The expected response was that magnetism had been induced in the first clip.

(ii) Candidates had to explain why no additional paper clips were added or

attached after the third clip.

This question was poorly done. Most candidates failed to demonstrate

understanding that the magnetic field becomes weaker away from the

electromagnet. Most of them seemed not to be keyed-in onto the fact that the

question was asking about the magnetic field strength around the electromagnet.

They thought that as more paper clips were added the magnetism of the

electromagnet became weaker which is incorrect. They failed to grasp that that

the strength of the electromagnet remained the same but the magnetic field

strength around the electromagnet became weaker the further one moves from

the electromagnet. Some thought that there was current moving in the clips,

hence cells had to be increased for the fourth clip to be attached, showing the

recurring challenge of confusing the concept of magnetism and static electricity.

The expected response was that the magnetism on the added paper clips was

weakened as the chain of attracted clips increased or as the attached paper clip

was further away from the electromagnet. That is why no additional paper clips

could be attached.

(iii) The candidates had to state and explain what happened when the switch was

opened.


38

This question was a bit difficult for the candidates with most of them having

language challenges as it demanded a qualitative explanation of the concept of

loss of magnetism by a temporary magnet when current is switched off. Some

candidates seemed to think that current starts flowing in a circuit when the switch

is opened which was the wrong premise for answering the question thus they

would say that the paper clips would be strongly attracted as there was more

current flowing in the circuit, and hence lost the marks.

For the candidates who knew that an open circuit was not working, they would

state that the paper clips would drop without advancing an explanation and lost

the second mark. Some candidates lost the second mark by saying the paper

clips would be demagnetised which was incorrect since it was the electromagnet

that got demagnetised. That is why the paper clips fall simultaneously, not one by

one, since the electromagnet loses its magnetism, not the paper clips.

Candidates earned the first mark by mentioning that the paper clips would drop or

fall-off from the electromagnet. This was because the electromagnet lost its

magnetism when the switch was opened, and this earned the second mark.

(c) (i) The question required candidates to suggest the number of paper clips that

could be attracted by the electromagnet when one more cell had been added to

the circuit.

This question was generally well done as most candidates suggested a

reasonable number of paper clips, more than the three in Table 2.1, that could be

attracted by the electromagnet. Some went for unreasonably large values above

ten which was unacceptable. Some decided not to commit themselves giving

vague responses such as more than three which did not earn the mark for lack of

delineation of the upper values. Some decided to make calculations and obtained

values such as 4.5 which was penalised because they had to round-off their

values to whole numbers as there are no half paper clips.

To earn the mark, candidates had to suggest a value above three but not more

than ten.


39

(ii) Candidates were expected to give an explanation for their answer in (c)(i).

The question was mildly accessible to the candidates. A number of them correctly

stated that increasing the number of cells increases the current or voltage in the

circuit which made them earn the first mark. They then had to state that this

increased the strength of the electromagnet in order to earn the second mark.

Some candidates noted that the addition of a cell increased the strength of the

electromagnet with no reference to the increase in current or voltage and lost the

first mark. Some recurringly explained using the concept of electrostatics, stating

that charges became stronger and lost the marks. Some gave their explanations

using ‘power’ which is a different concept to magnetism in Physics and incurred

some penalties.

(d) (i) The candidates were expected to predict the number of paper clips that would

be attracted if the number of turns on the electromagnet was increased to 60.

This question was well done as most candidates were able to predict a

reasonable number of paper clips, more than the number suggested in (c)(i)

and earned the mark. Even here, some went for unreasonably large numbers,

in excess of 20 which and were penalised. Some multiplied their numbers form

(c)(i) by two and managed to get the mark. Some unnecessarily calculated the

paper clips and got the marks since the values they obtained were whole

numbers unlike in (c)(i).

The expected response was a value more than the one given in (c)(i) but not

above 20.

(ii) Candidates were expected to give an explanation for their answers in (d)(i).

This question was done poorly as it was only a handful of candidates that

obtained both marks. The candidates were not aware that increasing the number

of turns around an electromagnet increases the intensity of the magnetic field

which makes the electromagnet stronger. Some thought increasing the number of

turns increased the current which was a bit irrelevant. Some would only refer to

the effect that increasing the number of turns had on the electromagnet without

mentioning the effect. The first mark was particularly inaccessible to the


40

candidates. Some used forces of attraction, that is, electrostatic forces to explain

the phenomena and lost marks. There were those who used the concept of power

even here and also lost marks.

The candidates had to state that increasing the number of turns around the

electromagnet increased the magnetic field around the solenoid or increased the

surface of the solenoid covered by the conductor in order to earn the first mark.

They earned the second mark by stating that this increased the strength of the

electromagnet.

(e) Candidates had to suggest a way of improving the accuracy of the experiment.

This was poorly done as a majority of the candidates failed give reasonable ways of

improving the accuracy of the experiment, an important scientific skill. Most candidates

correctly noted that the accuracy could be improved by repeating the experiment

several times but then neglected to mention that an average of the paper clips picked

had to be calculated and used for accuracy, thereby losing the mark. Some candidates

suggested that either a voltmeter or an ammeter could be added to the circuit which

was wrong. Some repeated the factors affecting the strength of an electromagnet and

also lost the mark.

There were a number of expected responses including that the experiment could be

done more than once and an average be taken; new cells could be used for each part

of the activity; a resistor could be added in the circuit to keep the current constant for

each part of the experiment or the use of a variable power supply which could supply a

consistent amount of current.

(f) Candidates were expected to describe an experiment carried out to show the

magnetic field lines around the electromagnet.

This was fairly well done as most candidates were able to get the first mark while the

other two marks were a bit inaccessible. The candidates seemed to fail to describe a

standard experiment to find magnetic field lines around a magnet. Most of those

candidates that described the experiment using iron filings neglected to mention that

the paper placed on the electromagnet had to be tapped gently for the field to be clear

and thereby lost the third mark. A number of those that forgot the word ‘tap’ had some

challenges describing this with attempts such as shaking the paper or moving the


41

paper around used, at times unsuccessfully. Some would mention that iron filings could

be sprinkled around the magnet without mentioning the use of a paper and lost the

second mark. Some candidates referred to iron filings as magnetic filings, iron files, fine

iron nails which was not accepted.

Candidates who opted to describe the experiment using a compass had serious

challenges with describing how the compass was used, hence lost two marks. They

neglected the placing of a paper above or below the electromagnet for recording the

field and lost the second mark. Some who remembered that a paper was placed would

fail to mention that the point had to be marked once the compass pointed in a certain

direction and also got penalised. They also could not describe the repetition of the

process several times around the electromagnet to come up with the field which led to

the loss of the third mark.

A significant number of candidates did not understand the question and used the right-

hand-grip rule to describe how they would find the magnetic field lines and lost all the

marks. Some suggested the use of a permanent magnet which was confusing the

demand of the question with stroking and also lost all the marks.

The candidates were expected to either describe the use of iron filings or a compass to

get the magnetic field.

Iron filings

The first mark was for mentioning the use of iron filings;

The second one for mentioning that a paper should be put on top of the electromagnet

and the iron filings sprinkled on the paper. The third mark was for describing that the

iron filings had to be tapped gently for the pattern to form.

Compass

The first mark was for mentioning the use of a compass; the second for explaining that

the compass could be placed on a paper placed above or below the electromagnet with

the compass placed at one end of the electromagnet such that the pointer points away

from that end and that point marked. The third mark was for stating that this procedure

had to be repeated until the other end of the electromagnet was reached. These points

could then be joined to give the field.


42

(g) Candidates had to explain the observation that no paper clips were picked by the

electromagnet when the iron core was replaced with an aluminium rod.

The question was poorly attempted by the candidates as most of them seemed

oblivious to the fact that aluminium is a non-magnetic material that cannot be

magnetised which was why the paper clips could not be attached when the switch was

closed.

A huge number of candidates were mentioning that aluminium was not a good

conductor of electricity and that was why it could not be magnetised which was untrue

and irrelevant to the question. Some thought that it was hard to magnetise aluminium

insinuating that aluminium is a hard magnetic material.

Some thought the aluminium had the same charge as the paper clips which was why

they repelled each other, which also manifested the confusion of magnetism and

electrostatics in a number of candidates.

The expected response was that aluminium was not a magnetic material.

examinations council of eswatini egcse

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