BP- 50
Register Number
Class
Name
BARTLEY SECON DARY SCHOOL
GCE O.LEVEL PRELIMINARY EXAMINATIONS
PHYSICS
6091/01
Sec 4 Express
Paper 1 Multiple Choice
18 Sep 2020
t
hour
Candidates answer on the Multiple Choice Answer Sheet.
Additional Materials: Multiple Choice Answer Sheet
READ THESE INSTRUCTIONS FIRST
Write your class, register number and name on all the work you hand in.
Do not use staples, paper clips, highlighters, glue or correction fluid.
fofi
questions in this paper. Answer all questions. For each question there are four possible
answers, A, B, C and D.
There are
Choose the one you consider correct and record your choice in soft pencil on the separate
Multiple Choice Answer Sheet.
Read the instructions on the Answer Sheet very carefully.
Each correct answer will score one mark. A mark will not be deducted for a wrong answer.
Any rough working should be done in this booklet.
The use of an approved scientific calculator is expected, where appropriate.
At the end of the examination, submit the Multiple Choice Answer Sheet.
This document consists of 17 printed pages and
I blank page.
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Answer al! questions.
For each question, there are four possible answers A, B, C and D.
Choose the one you consider correct and shade your choice on the Multiple Choice Answer Sheet.
1
Which pair of physical quantities consists of two vectors?
A
B
G
D
2
kinetic energy and force
moment and time
velocity and acceleration
weight and temperature
A simple pendulum is '1.0 m long and carries a 50 g bob.
It swings with a period of 0.80 s.
lf the 50 g bob is replaced by a 100 g bob, how long does the new pendulum take to complete
1 swing?
3
D
C 1.6s
B 0.80s
A 0.40s
3'2s
A ball made of plasticine is thrown vertically upwards towards the ceiling. At the highest point of
its path, it is stuck at the ceiling.
Which distance.time graph best describes the motion of the ball?
AB
distance/m
distance/m
time / s
time / s
c
D
distance / m
distance / m
time / s
time / s
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4
The diagram shows a velocity{ime graph of an object moving from rest along a straight line.
velocity / m
s-1
80
60
40
/
20
0
/
/
\
/
\
1
0
Ic
\
-24
4
5
0
time I s
{
\
-40
What is the displacement of the object at time = 40 s?
l\ 550m
5
B 850m
C
D
1050m
1250m
An engine pulls a truck at constant speed on a leveltrack.
engine
link
truck
track
w
The link between the engine and the truck breaks. The driving force on the engine remains
constant.
What effect does this have on the engine and on the truck?
engine
truck
A
speed stays constant
slows down
B
speed stays constant
stops immediately
c
speeds up
slows down
D
speeds up
stops immediately
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6
A helicopter moves through the air and ascends against a total resistive force of 2 000 N. The
propeller on the helicopter sweeps the air downwards with a force of 4 200 N.
resistive force on
helicopter, 2 000 N
direction of
motion of
helicopter
force on air due to
propeller, 4 200 N
What is the upward force on the propeller due to the air?
A 2000N
I
G
B 2200N
4200N
D
6200N
James hung a ball to the ceiling of his car using a thin thread. The figure below shows the ball
when the car is at rest.
What is the position of the ball when his car starts moving to the left?
ABC
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The following table shows the results of an experiment in which a solid material is placed in four
different liquids.
density of liquid / kg
liquid
mercury
water
rn-e
observation
13 600
floats
I
floats
000
turpentine
700
sinks
organic compound
550
sinks
What is the density of the solid material?
A
B
G
D
9
exactly 700 kg
m-a
exactly 1000 kg
m-3
between 700 kg m-3and 1 000 kg
m-3
between 1 000 kg m-3and 13 600 kg 6-a
A spacecraft travels from the Earth to the Moon.
At a certain point in the journey, it has zero weight.
Why is the weight zero atthis point?
A
B
C
D
10
The gravitational fields of the Earth and the Moon cancel each other.
The spacecraft leaves the Earth's atmosphere.
The spacecraft stops moving.
There is no air resistance on the spacecraft.
The diagrams show four table lamps with their centre of gravity, M.
Which lamp is the most stable?
ABC
D
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11
The diagram shows four balls, A, B, C and D.
Which ball is in a state of stable equilibrium?
B
D
A
c
12
A car of mass 500 kg is at rest at point X on a slope, as shown. The car's brakes are released
and the car rolls down the slope with its engine switched off. At point Y, the car has moved
through a vertical height of 30 m and has a speed of 11 m/s.
mass = 500 kg
speed = 0 mis
30m
speed = 11 mls
Y
The gravitationalfield strength, g, is 10 N/kg.
What is the energy dissipated by frictionalforces when the car moves from X to Y?
A 3.0x10al
13
B 1.2x1OsJ
C 1.5x10sJ
D
1.8x10sJ
An electric motor runs on 24OV a.c. supply with a current of 5.0 A. The electric motor raises a
load of 2 000 N vertically through a distance of 12 m.
The motor is operating at 80 % efficiency.
What is the time taken to raise the load?
A
0.050 s
B
G
16s
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D
25s
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14
The diagram shows a manometer containing mercury that is sealed at one end
vacuum
d
mercury
What happens to the distance d when the manometer is taken to the top of a mountain?
A
B
C
D
15
lt decreases, because atmospheric pressure decreases with height.
lt decreases, because atmospheric pressure increases with height.
lt increases, because atmospheric pressure decreases with height.
lt increases, because atmospheric pressure increases with height.
Two vessels are joined together with a tube and filled with water. Both vessels are open at the
top.
water
P
a
o
R
{
>
How does the water pressure at point R compare to the water pressures at points P and Q?
pressure at R
pressure at R
A
greater than at P
lower than at Q
B
greater than at P
same as at Q
c
same as at P
lower than at Q
D
same as at P
same as at Q
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6
A girl measures the resistance of a metal wire at the ice point and at the steam point. She records
her results.
temperature
resistance /
ice point
15.0
steam point
20.0
C)
What is the temperature when the resistance of the wire is 14.0 A?
A
17
-20
B
"C
c
*17"C
D
17"C
20',C
The temperature of a gas in a rigid container is increased
Which property of the gas must also increase?
A
B
C
D
density
internalpotentialenergy
pressure
volume
1B The diagram below shows a wooden bar and a copper
bar joined together at one end with a
piece of paper wrapped tightly around the centre.
wood
copper
s
paper
flame of
bunsen burner
Heat is applied from the flame of a bunsen burner at the paper and the paper goes brown on
one side only.
Which side of the paper goes brown and what can we conclude about wood and coppeP
brown side
copper
wood
A
copper
good conductor of heat
poor conductor of heat
B
copper
poor conductor of heat
good conductor of heat
G
wood
good conductor of heat
poor conductor of heat
D
wood
poor conductor of heat
good conductor of heat
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19 An experiment to study heat transfer is shown
below. A light bulb is tumed on and two
thermometers X and Y are clamped at the same distance from it. A shiny aluminium foil and an
aluminium foil painted black are inserted between the light bulb and the thermometers. The
temperatures on both thermometers are recorded every minute.
thermometer X
shiny aluminium foil
thermometer Y
atuminium foil painted black
Which set of graphs correctly shows how the temperature measured by each thermometer
varies with time?
A
B
temperature / K
temperature / K
X
Y
Y
X
f/min
f/min
c
D
temperature / K
temperature / K
Y
Y
X
f/min
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20 Wooden boxes P and Q each contain a hot pot. ln box P, the hot pot is surrounded
by leaves
and branches.
leaves and
branches
air
hot pot
wooden box
o
P
Which statement is true?
A
The hot pot in P will lose heat at a faster rate than the hot pot in Q as the leaves and
branches increase heat loss by convection.
B
The hot pot in P will lose heat at a slower rate than the hot pot in Q as the leaves and
branches reduce heat loss by convection.
C
D
21
The hot pot in Q will lose heat at a faster rate than the hot pot in P as air is a good conductor
of heat.
Both hot pots in P and Q will lose heat at the same rate as they are housed within the same
type of wooden box.
A solid substance is heated at a constant rate. The solid changes into a liquid and then into a
gas.
The graph shows how the temperature of the substance changes'
temperature
l"c
7oo
600
500
400
300
200
100
0
0
40
2A
60
80
100
120
time/s
Which statement is mrrect?
A
B
C
D
The specific heat capacity of the gas is lower than that of the liquid.
The specific heat capacity of the gas is the same as that of the tiquid.
The specific heat capacity of the liquid is lower than that of the solid.
The specific heat capacity of the liquid is the same as that of the solid
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22
The energy required to change liquid water into water vapour at the same temperature is called
latent heat of vaporisation.
What does this energy do?
A
B
C
D
lt increases the average separation of the water molecules.
lt increases the average speed of the water molecules.
lt raises the temperature of the air near the water.
lt splits the water molecules into their separate atoms.
23 A student generates
a transverse wave in a long rope. He makes 2 oscillations in 1.6 s. The
diagram shows the displacement-distance graph of the wave. The wave is travelling to the right.
displacement
distance
Which diagram correctly represents the shape of the rope 0.20 s later?
AB
displacement
displacement
distance
distance
c
D
displacement
displacement
distance
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24
ln which situation is the wavelength of the wave changed?
A
B
C
D
25
lnfra-red radiation from the Sun passing from air into water.
Radio waves travelling through space.
Sound waves reflected off a wall.
Water waves travelling in a swimming pool of uniform depth.
Which applications use X-rays?
I
ll
lll
A
B
C
D
detecting flaws in metals
detecting metal in luggages at airports
detecting bone fracture in human body
llonly
I and lllonly
ll and lll only
I and
all of the above
26 The diagram below shows the image of a clock as seen in a plane mirror.
What is the actualtime on the clock?
A 3:05
27 What are the characteristics
A
B
C
D
B
C
3:55
8:05
D
8:35
of an image formed by the thin converging lens in the human eye?
real, inverted and diminished
real, upright and diminished
virtual, inverted and diminished
virtual, upright and magnified
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28 An astronaut uses a walkie-talkie
radio to communicate with his fellow astronauts inside the
space shuttle some distance away.
@s
6ffi!'
/6,6
5E
astronaut
space shuttle
What is the conect nature and sequence of the two types of waves used during the
communication?
A
B
C
D
longitudinal
+
transverse
longitudinal
--+
transverse ---) longitudinal
transverse --t longitudinal
transverse ---) longitudinal ---) transverse
29 Which statement
A
B
C
D
about sound waves is correct?
Loudness depends on amplitude and pitch depends on frequency.
Loudness depends on frequency and pitch depends on amplitude.
Loudness depends on velocity and pitch depends on wavelength.
Loudness depends on wavelength and pitch depends on amplitude
30 Two metal spheres
in contact are suspended by threads. Sphere Q is earthed
positively-charged
rod
When a positively-charged rod is held close to P, what would be the net charge on each sphere?
P
o
A
negative
positive
B
negative
no charge
c
positive
negative
D
positive
no charge
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31 Which statement
A
B
C
D
32
about electric current is conect?
lt is the rate of flow of charge and its unit is the ampere.
lt is the rate of flow of charge and its unit is the coulomb.
lt is the rate of work done per unit charge and its unit is the ohm.
lt is the rate of work done per unit charge and its unit is the volt'
Wire X has a resistance of 9.0 O.
Wire Y is made of the same material as X but is ha/ce as long and has a diameter three times
larger.
What is the resistance of wire Y?
83 The diagram
D
c 54c-
B 6.0r)
A 2.OA
shows part of an electrical circuit with four different resistors.
2.0
P
6.0
0
0
o
I
T
4.0 0
3.0
0
R
Across which junction will the maximum effective resistance be achieved?
A
PQ
B
PR
c
QS
D
SR
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34 A.22 Q resistance wire XY is 5.0 m long and is connected in the circuit shown
24V
X
.r9 a
2.0
4.0 m
Y
a
What is the reading on the voltmeter?
A 17.6V
35
B
c
19.6V
21.6V
D
22.0V
A fuse is connected to the neutralwire of atan.
Which statement(s) is/are correct?
I
ll
lll
A
B
C
D
The fan will be safe to touch when the fuse blows.
The fan will not operate if the fuse blows.
The fan will still be connected to the high voltage source even after the fuse blows.
llonly
land lllonly
ll and lllonly
I and
all of the above
36 The power
produced in a resistor is
P.
The voltage across the resistor is then doubled.
What is the new power produced in the resistor?
Ai P
BP
c2P
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37 The diagram shows
how a steel bar can be magnetised
d.c. supply
+
,
steel bar
Which statement describes how the steel bar can be demagnetised?
A
B
C
D
Reverse the d.c. supply and gradually decrease the cunent in the circuit.
Reverse the d.c. supply and gradually increase the current in the circuit.
Use an a.c. supply and gradually decrease the cunent in the circuitUse an a.c. supply and gradually increase the cunent in the circuit.
38 The diagram shows a bar magnet on a turntable.
A plotting compass is placed in front of the
magnet as shown.
turntable
S
magnet
N
plotting
compass
When the turntable rotates in a clockwise direction, what would be observed?
A
B
C
D
The compass needle does not move.
The compass needle oscillates.
The compass needle rotates anticlockwise.
The compass needle rotates clockwise.
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39
The diagram shows a small plotting compass placed above a copper wire. When there is no
current in the wire, the plotting compass points to the North.
N
direction of
current in wire
I
compass
copper wire
A large current is passed through the wire. The direction of the cunent is shown above.
Which diagram shows what happens to the compass needle when the current is passed through?
A
B
c
D
l
------+
I
40 The diagram shows
I
a small magnet hanging on a thread near a wire coiled around a hollow
plastic tube.
hollow plastic tube
What happens to the magnet when an iron core is inserted into the hollow tube?
A
It moves away from the tube.
B
It moves towards the tube.
c
It rotates 180
o
and move away from the tube.
D
It rotates 180
o
and move towards the tube.
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Register Number
Class
Name
BARTLEY SECON DARY SCHOOL
GCE O.LEVEL PRELIMINARY EXAMINATIONS
PHYSICS
6091/02
Sec 4 Express
2 Sep 2020
Paper 2 Theory
t
hours 45 minutes
Candidates answer on the Question Paper
Additional Materials: NIL
READ THESE INSTRUCTIONS FIRST
Write your class, register number and name on all the work you hand in
Write in dark blue or black pen on both sides of the paper.
You may use a soft pencil for any diagrams and graphs.
Do not use staples, paper clips, highlighters, glue or correction fluid.
Section A
Answer all questions.
Section B
Answer all questions. Question 12 has a choice of parts to answer.
Candidates are reminded that all quantitative answers should include appropriate units.
The use of an approved scientific calculator is expected, where appropriate.
Candidates are advised to show all their working in a clear and
orderly manner, as more marks are awarded for sound use of
For Examiner's Use
Physics than for correct answers.
Section A
At the end of the examination, submit this question paper.
The number of marks is given in brackets [] at the end of each
guestion or part question.
Section B
Total
This document consists of 21 printed pages and 1 blank page.
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Section A
Answer all the questions in the spaces provided.
1
Fig. 1.1 shows a student using a metre rule to determine the diameter of a ball bearing. Five ball
bearings are lined up beside each other with two wooden blocks supporting them at the sides.
block
ballbearings
Fig. 1.1
(a)
Determine the average diameter of one ball bearing.
diameter =
(b)
t1I
Suggest another instrument that could be used to measure the diameter of the ball
bearing. Explain why the instrument you suggest is a better way of measuring the
diameter of the ball bearing.
l2l
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2
Fig.2.1shows the horizontal forces acting on a moving car. The forward driving force remains
constant throughout the journey.
total resistive force
forward driving force
<-
Fig.2.1
-)>
Fig.2.2 shows how the total resistive force that acts on the car varies with time.
Fig. 2.3 shows the speed-time graph for the firsl24 s of the motion of the car along a straight
road.
total resistive force / N
2 000
Fa
I
time i s
Fig. 2 .2
20
18
speed
16
mis
14
12
10
8
6
4
2
0
0 24
6
81012141618202224
time / s
Fig.2.3
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(a)
(i)
At what time did the forces acting on the car become balanced?
(ii)
Determine the driving force of the car
driving force =
(b)
11I
Describe and explain the motion of the car between 8.0 s to 14 s of its journey
..t11
(c)
The car has a mass of 800 kg.
(i)
Calculate the resultant force of the car for the first 8.0 s of the journey
resultant force
(ii) Determine
=
.......121
the total resistive force, Fn, otr the car during the first 8.0 s of the journey.
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3
Fig. 3.1 shows a man sitting on a plastic chair. Fig. 3.2 shows the same man with his plastic
chair tilted backwards slightly.
Fig.3.1
Fig.3.2
The chair and man fall over if the chair is tilted far backwards than in Fig. 3.2.
Explain why.
..121
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4 (a) Define pressure.
11I
(b)
Fig. 4.1 shows two vertical tubes P and Q, each closed at the upper end. The space above
the mercury meniscus in tube P is vacuum. On the other hand, there is a small amount of
air in this space in tube Q. The density of mercury is 13 600 kg/m3.
PO
76 cm
60 cm
mercury
Fig.4.1
(i)
Determine the atmospheric pressure in Pa.
pressure =
(ii)
....Pa [2]
Determine the pressure, in Pa, exerted by the air in the space at the top of tube Q.
pressure
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......Pa121
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7
5
A marble of mass of 15 g is released from a slope shown in Fig. 5.1. The radius of the loop, R,
is 20 cm.
marble
h
Fig.5.1
lf the marble were to complete its path along the track without falling off the loop, it must maintain
a speed of at least 2.0 m/s.
(a)
State what is meant by mass of the marble.
..
t1l
(b) On Fig. 5.1, mark, with an X, the position on the loop where the marble has the slowest
speed.
(c)
t1I
Calculate the minimum kinetic energy of the marble at the point marked in (b).
kinetic energy =
(d) Thus, calculate the minimum height
121
needed to release the marble so that it will be able to
complete the track without falling off.
minimum height =
(e) state an assumption that you had made when calculating the height
l2l
in (d)
...I11
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6
Fig. 6.1 shows the cross section of a cup noodle.
Fig.6.l
(a) The container
of the cup noodles is made of expanded polystyrene.
State and explain one advantage of using such a material to make the container.
t2l
(b)
Explain why the inner surface of the lid is usually shiny.
Lzl
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7
A water wave is produced in a ripple tank. Fig. 7.1 shows lhe wavefronfs of a water wave in a
ripple tank.
Fig.7.1
(a)
Explain what is meant by a wavefront.
.t1I
(b)
Fig. 7.2 shows how the height of water at the same place in the tank for two waves P and
Q varies with time f. The mean level is marked as 0.
wave P
height
of water
0
ilrn$
wave Q
height
of water
0
0
500
1
t/rn$
Fig.7.2
(i)
Based on Fig. 7.2, state one difference and one similarity of the two waves.
difference
similarig
121
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(ii)
The speed of the water wave is 0.20 m/s.
Determine the wavelength of wave P.
wavelength
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8
Fig. 8.1 shows a 60 O resistor and a thermistor connected in series with an ammeter and a
battery of electromotive force of 6.0 V. The alarm bell will trigger when the potential difference
across it is more lhan 2.0 V. Assume that the alarm bell takes in negligible cunent.
60c)
6.0v
-
alarm
bell
thermistor
Fig. 8.1
(a)
Define electromotive force.
t1I
(b) The ammeter reads 0.025 A.
(i)
(ii)
(ii)
On Fig. 8.1, mark the positive and negative terminals of the ammeter using "+" and "-"
respectively.
t1I
Calculate the potential difference across the 60 O resistor,
potential difference =
121
resistance =
.....121
the resistance of the thermistor.
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(c)
The resistance of the thermistor varies with temperature as shown in Fig. 8.2.
resistance / O
-10
0
10 20 30 40 50 60 70 80 90
temperature
100
i'C
Fig.8.2
(i)
Determine the temperature range that the alarm bellwill trigger'
temperature range
(ii)
.t3I
State one practical application in which an alarm bell is triggered for the temperature
range determined in (c)(i).
tlI
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I
Fig. 9.1 shows a part of the mains electrical circuit in a house. The three lamps and the fan are
connected to the live and neutral wires of the mains supply of 24A V.
-,
I-
double
insulation
motor
I
fan
I
I
Y
l- _ _ r
5.0 A
Z
double
insulation
live
neutral
Fig.9.1
(a)
(b)
State the colour of the rubber insulation for the live and neutral wires.
r
insulation for live wire
._.tl
r
insulation for neutralwire
..I11
l
Each lamp is rated at "60 W, 24A\f'and the fan is rated at "1 000 W, 240 V".
Calculate the appropriate fuse ratings for fuses Y and Z.
fuse Y rating =
fuse Z rating =
t3l
(c)
All lamps and the fan are turned on for 5.0 hours each day.
The cost of electricity supplied is $0.19 per kWh.
Calculate the weekly cost of using the lamps and fan
total cost =
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Section B (30 marks)
Answer all the questions in this section.
Answer only one of the two alternative questions in Question 12.
10
When a piece of glass is placed in a liquid of exactly the same refractive index as the glass, the
glass seems to diiappear. This method is used to determine the refractive index of a small piece
of glass found at an accident.
The tables in Fig. 10.1 give the refractive indexes of some types of glass and of some liquids.
type of glass
liquid
refractive index
refractive index
bottle glass
1.524
cinnamon oil
1.601
car headlight glass
1.478
glycerol
1.466
crown glass
1.606
olive oil
1.460
flint glass
1
silicone oil
1.520
spectacle glass
1.525
water
1.333
.60 1
Fig. 10.1
(a)
One of the types of glass in Fig. 10.1 seems to disappear in one of the liquids.
State the type of glass and the liquid.
(b)
The values of the refractive index of the glasses and liquids given in the table are for yellow
light.
(i)
State the value of the speed of light in a vacuum.
I1I
(ii) State the type of glass or liquid in Fig. 10.1 in which yellow
light travels the slowest.
....t11
(iii)
Calculate the speed of yellow light in water
soeed =
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(c) Arectangularpieceof glasswasfoundatthesiteof
theaccident. Fig. l0.2showsthepiece
of glass placed in silicone oil and Fig. 10.3 shows the same piece of glass placed in glycerol.
I
I
t
I
weak ht
reflected I
ray
,t' weak
I
,
glass
glass
silicone oil
glycerol
Fig.1O.2
reflected
Fig. 10.3
Light is incident on the vertical faces of the piece of glass. The different parts of the light are
shown.
There is no refracted ray of light inside the glass in Fig. 10.2.
(i)
Using ideas about the angle of incidence, critical angle and refractive index, explain
why the rays of light do not enter the glass in Fig. 10.2.
I3I
(ii) The piece of glass shown in Fig. 10.2 and Fig. 10.3 is one of the types of glass shown
in the table in Fig. 10.1.
State which type of glass was found at the site of the accident and explain how you
determined the answer.
l2l
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16
11 (a) Fig.
1 1.1 shows a circuit breaker. lt is a safety device to switch off a circuit if the current
becomes too large. The current enters at terminalA and leaves at terminal B.
iron armature
coil
tron core
spring
B
Fig. 11.1
(i)
Explain how this circuit works.
t3l
(ii)
The iron core is removed.
1.
State the effect that this has on the magnetic strength of the coil
........t1
2.
l
Name one other way to enable the circuit breaker to operate under the same
current condition as before.
..11
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(b)
One end of a thin copper rod is freely suspended at pivot A and the other end is immersed
in a small pool of mercury. The copper rod is held vertically in the magnetic field of a
horseshoe magnet as shown in Fig. 11.2. A battery is connected in series to the circuit.
pivot
copper rod
+
lt'-
mercury
switch
eye -4
observer's
(facing the side of the magnet)
Fig.11.2
(i)
When the switch is closed, a cunent passes through the copper rod.
Describe and explain what happens to the rod as seen from the observe/s eyes.
l3I
(ii)
The switch is now open. Fig. 11.3 below shows the top view of the two ends of the
horseshoe magnet and the copper rod.
Sketch the magnetic field pattern between the two ends of the magnet.
copper rod
I
I
I
I
I
I
?
a
N
Fig. 11.3
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12 EITHER
Fig. 12.1shows part of a hydraulic jack used to lift the front of a car
hydraulic
oil
of
large
piston
pulling forceby operator
small
piston
50 cm
handle
pivot
arm
25 cm
pivot
Fi1.12.1
The operator pulls the handle using a force of 60 N. This action produces a lorye on the small
piston. The force exerted by the hydraulic oil on the large piston increases to F. The large piston
moves and rotates the arm about another pivot, which then raises the front of the car'
The cross-sectional area of the small piston is 1.5 cm2, while the cross-sectional area of the
large piston is 5.0 cm2.
(a)
Calculate
(i)
the force acting on the small piston,
force acting on the small Piston =
(ii)
l2l
the pressure in the oil caused by the force on the small piston,
pressure
(iii)
the value of F
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(b) Suggest one modification that can be made to the handle in order to produce a larger
magnitude of F.
t1I
(c)
Using the concept of work done, compare the distances moved by the large and small
pistons. Explain your answer.
....121
(d) Air bubbles form in the hydraulic oil of Fi1.12.1. As air is compressible,
that this has on the operation of the hydraulic jack.
explain the effect
l2l
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12 0R
Fig. 12.2 shows the apparatus used to measure the specific latent heat of fusion of water.
to power supply
electric heater
crushed ice at 0
'C
funnel
glass beaker
a
Fi1.12.2
The heater is switched on and water drips into the beaker at a constant rate.
ln 120 s, 31 g of water drips into the beaker. The power of the heater is 85 W.
You may ignore heat transfer to the ice from the room.
(a)
Calculate the amount of electrical energy supplied to the heater in 120 s.
energy =
(b)
._.__t2l
Hence, calculate the specific latent heat of fusion of water.
specific latent heat =
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(c)
With reference to the kinetic model of matter, describe the changes to the water molecules
during the melting process.
I3l
(d)
ln another experiment using the same heater, ice at a temperature of
-
4"C is used
Explain why a smaller mass of water drips into the beaker in 2.0 minutes.
t1l
(e) After the water has been collected in the beaker, the beaker was heated over a Bunsen
bumer, and the temperature of the water was recorded.
Thermal energy is transferred to the water at a constant rate but the temperature of the
water does not increases at a constant rate, as shown in Fig. 12.3.
1
80
temperature I oC
60
40
20
0
50
100
150
f/s
200
250
Fig. 12.3
Describe how the temperature of the water changes. suggest a reason for this.
.......... t2I
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4E1 Phy Prelim Exam2020 Suggested Marking Scheme
Paper
I [40 marksl
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Q8
Q9
Q10
c
B
A
B
c
c
B
c
A
A
Q11
Q12
Q13
Q14
Q15
Q16
Q17
Q18
Q1e
Q20
c
B
D
A
B
A
c
c
D
B
Q21
Q22
Q23
Q24
Q25
Q26
Q27
Q28
Q29
Q30
A
A
A
A
D
c
A
B
A
B
Q31
Q32
Q33
Q34
Q35
Q36
Q37
Q38
Q39
Q40
A
A
c
A
c
D
c
c
D
B
Paper 2 Section A [50 marksl
1(a)
(b)
diameter
=
3.5 /
5 =
0.70 cm or 0.7
Vemier caliper or micrometer screw
cm
41
gauge.
81
These instruments have better precision and give more precise
answers.
Bl
(accept answer if students mention that the smallest unit the instrument can measure is
0.01 cm or 0.01 mm respectively)
s
(iil 2000N
2(a)(i)
(b)
Al
Al
14
From 8.0
sta14s, the car moves with decreasinq acceleration
as the resultant force
decreases due to driving force stays constant while total resistive force
(cXi)
a
=
v-u
12.8
t
-
increases.
B't
O
C1
8.0
1.6 ms-2
F=ma
(c)(ii)
3
2 000
800
- Fn =
1280N
Fn=
720 N
x 1.6
1280N
Allow ECF from (a)(ii) and (c)(i)
A1
cl
A1
The line of action of the man's weiqht falls outside the base area of the chair.
(Or CG is lowered)
B1
Thus the weiqht oroduces anticlockwise moment about the point of contact between
4(a)
chair's leg and the floor, causing the man to fall.
B1
lt is the force acting per unit area.
B1
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4E1 Phy Prelim Exam2020 Suggested Marking Scheme
(bxi) P"t'
(bxii)
Psas
=
=
=
=
0.76 (13 600X10)
C1
103 000 Pa (3 s.f.)
A1
Pam
103
-
(0.60X13 600X10)
360-81
Allow ECF from (b)
600
Pa
21 800 Pa or 22 000
c1
A1
(3 s.f.)
Mass of the marble is the amount of matter in the marble.
B1
(b)
X is at the top of the loop
B1
(c)
KE =
=
=
GPE =
5(a)
(d)
Ytmv2
%xA.$5
A1
0.030 J
mgh
loop
of release
GPE at top of
Heisht
c1
x2.Az
=
0.015 x 10 x
0.40 =
0.060) / (0.015 x
=
c1
0'060 J
10)
Allow ECF from (b)
:r#:.
A1
It is assumed that there is no work done aoainst friction alonq the slope or aqainst air
(e)
B1
resistance.
6(a)
Polystyrene has pockets of air and air is a poor conductor (good insulator) of
heat.
81
Heat is conducted slowlv to the hands which hold the cup, so hands won't get scalded.
B1
(b)
7(al
(bxi)
(ii)
Shiny surface are poor absorbers of radiation OR oood reflectors of radiation.
B1
It will reduce the rate of heat beinq lost bv radiation.
B1
lt is an imaoinary line ioining points that are in phase-
Or it is a line that ioin all peaks of a wave.
B1
Difference: Q has a qreater amplitude (or maximum height, peak to peak) than P
B1
Similarity: Both waves have same frequencv / same oeriod / are transverse waves
B1
A
vlt
OR
A
vT
0.21
3.3 0R
A
0.2 x 0.3
A1
0.060 m
8(a)
cl
E.m.f is the work done by an electrical energy source to drive a unit charqe around a
B1
complete circuit.
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4E1 Phy Prelim Exam 2020 Suggested Marking Scheme
(bxi) "*" terminal on left side of ammeter
(ii) V
=
"-'
and
terminal on right side of ammeter
lR
(o-o25x6o)
c1
=
(iii)
A1
p.d. across thermistor
6.0
-
=
1.5
4.5
4.5
Resistance of thermistor
6.0
240
-60
180
Atlow ECF from (i)
0
240 A
0.025
Resistance of thermistor =
V
180
0.025
Total resistance of circuit =
(cXi)
B1
0
c1
A1
l
alternative
solution
c1
A1
Let Rrn be resistance of thermistor.
60
c1
C1
A1
(ii) Alarm is triggered
o
for any one of the following situations:
B1
to alert users if afreezer door is left open and the temperature inside freezer
exceeds 6'C.
o
if cooling unit in afreezer malfunction and temperature inside freezer > 6"C
Accept any other logical and complete answers.
e(a)
insulation for live
wire:
lnsulation for neutral
(b)
(c)
wire:
brown
B1
blue
B1
l=PA/
Current through all 3 lamps =
Current through the fan
=
Cunent through fuse Z
=
Fuse rating for Y
=
Fuse rating for Z
=
Total kWh used per week
=
1 O00l24O =
3 x 60/240
4.17
A+
0.75 A
4.17 A
0.75 A = 4.92 A
-l
.t
at least 2 out of
3 calculations
A1
1.0 A
A1
5.0 A to 7.0 A
A1
(3.0x0.060 + 1)x5x7
c1
41.3
Total cost
41 .3 x
$7.85
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$0.19
A1
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4El
Phy Prelim Exam 2020 Suggested Marking Scheme
Section C
10(a)
(bxil
(ii)
(iii)
Flint glass and cinnamon oil
B1
3.0 x 108 m/s
A1
crown glass
speed of light in vacuum
n
speed of light in water
3.0
1.333
108
Allow ECF from
speed of light in water
speed of light in
(cXi)
x
water
(b)(i)
C1
A1
2.25 x 108 m/s
The rays undergo total internal reflection within silicone
oil'
81
ln Fig. 10.2, the anqle of incidence of the lioht ravs at the oil-qlass boundarv is larqer
than the critical anqle of silicone
oil.
81
This must mean that silicone oil is optically denser than the
glass,
81
Or the refractive index of silicone oil is larqer than the refractive index of the qlass.
(ii)
The glass that fits these is car headlioht qlass.
B1
From Fig. 10.2 and Fig. 10.3, we know that the refractive index of the qlass is
between that of glycerol's 1.466 and silicone oil's 1.520.
11(aXi)
B1
When normal current flows, the coil becomes an electromaonet but it is not strong
enouqh to attract the iron
armature.
81
When the current becomes too larqe, the electromaqnet becomes stronqer and it now
attracts the iron
armature.
81
The iron armature loses contact with the sprinq and the circuit is open. No more
current can
(ii) 1.
2.
(bxi)
flow.
81
Maonetic strenqth of the coil becomes weaker.
B1
lncrease the number of turns per unit lenqth of the coil.
B't
The observer sees the copper rod moves to the
right.
81
The maqnetic field around the rod interacts with the maqnetic field of the maqnet,
resulting ;n one reqion of hioher maqnetic strenqth and another region of weaker
maqnetic
strenqth.
81
Thus a force is produced whose direction is determined usinq Flemino's Ieft hand rule.
B1
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93
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4El
Phy Prelim Exam 2020 Suggested Marking Scheme
(i
i)
I
I
V
o
N
.
.
Uniform field, i.e. horizontal lines spaced equally apart and curved at top and
bottom ends of magnets
B1
Correct direction of field lines
B1
12 EITHER
(aXi) Moment about pivot
Force on the small
(ii)
P
(iii)
(b)
Force
=
piston
60x50
3 000
=
F
120
A
1.5
25
3 000 Ncm
M1
120 N
A1
Accept ECF from (a)(i)
= 80 N/cm2 or 800 000 N/m2
80x5 = 400N
Accept EGF from (a)(ii)
A1
B1
lncrease the lenqth of the handle and applv force at end of the handle.
Shift the pivot on the handle closer to the small piston.
and
as force x distance moved.
Work done at both oistons is the same
B%
work done is calculated
B%
Since the force at the larqe piston is larqer than the force at the small
piston,
the distance moved by the larqe piston is shorter than that moved by small
(d)
cl
A1
Any one of the following answer:
r
.
(c)
S
piston.
Byz
B%
As air is compressible, the pressure transmitted to the larse piston will be smaller.
B1
Hence the force produced at the larqe piston will be smaller.
B1
Thus it becomes more difficult to lift the car.
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4E1 Phy Prelim Exam2A2A Suggested Marking Scheme
12 0R
(a)
E = Pt
(b)
10 200
=
=
It
10200
Or
lr
(c)
= 85x120
=
A1
10 200J
Allow EGF from (a)
0.031 x /r
A1
3.29x10s Jlkg
=
=
c1
31xlt
A1
329 Jlg
The motion of the molecules changes from vibratinq about their fixed positions to slidinq
over each
other.
81
The intermolecular forces change from beinq very stronq to beinq stronq. but weaker than
those in
solid.
Bl
The ananqement of the molecules changes from beino closelv oacked in a reqular pattern
with verv little space between molecules to molecules arranqed randomlv with little space
between
molecules.
81
Alternative answer
B%
fnermat enerqv is absorbed to b
B%
The molecules qet further apart as their potential enerqy increases.
The molecules are able to slide over each other instead of vibratino in fixed positions. B1
The averaqe speed of the molecules increases sliohtlv onlv / do not increase as their
kinetic energv remain
constant.
81
(d)
Some enerqv is used to raise the temoerature of the ice to its meltino point of 0 'C, thus
81
less eneroy is available to melt the ice.
(e)
Temperature rises at a decreasing rate.
As temperature rises, rate of heat loss to the surroundinq by radiation is increasinq.
partnerlnLe..ifrg
95
B1
B1