kranji prelim09 5116 p2 with keys

8/14/2019 Kranji Prelim09 5116 P2 With Keys

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Centre Number Candidate Number

Candidate Name: ______________________ Class: _____

KRANJI SECONDARY SCHOOLPreliminary Examination 2 Secondary 4 ExpressSecondary 5 Normal (Academic)

SCIENCE 5116/02, 5117/02

PAPER 2 Science (Physics)

Thursday 17 September 2009 1 hour 15 minutesKRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJIKRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI

KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJIKRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI

READ THESE INSTRUCTIONS FIRST

Write your name, index number and class on all the work you hand in.Write in dark blue or black pen.You may use a soft pencil for any diagrams, graphs, tables or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.

Section A (45 marks):Answer all questions.Write your answers in the spaces provided on the question paper.

Section B (20 marks):Answer any two questions.Write your answers on the lined pages provided and, if necessary, continue on separateanswer paper.

At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each question or part question.

FOR EXAMINERS USE

TOTAL

Set by : Mr Malek

This document consists of 11 printed pages and 3 lined pages.[Turn Over

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Kranji Prelim09 5116 P2 (+ans) 10/8/20092

SECTION A (45 MARKS)

Answerall the questions.

Write your answers in the spaces provided on the question paper.

1 a) When two forces of 5.0 N are added, they may produce a resultant force that

has a value ranging between 0.0 and 10 N.Describe how it is possible to produce a resultant force of

(i) 0.0 N, [1]

_______________________________________________________

_______________________________________________________

(ii) 10 N. [1]

_______________________________________________________

_______________________________________________________

b) The diagram below shows a can of paint lifted by using two ropes A and B.

The angle between the two ropes is 90o. The ropes are as indicated by the

broken lines in the diagram. The tension on rope A is 140 N and is drawn toscale. The scale used is 1.0 cm represents 20 N.

Rope B64 N

Rope A140 N

90o


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(i) Using this same scale, draw on the diagram, the correspondingtension of 64 N on the rope B. [1]

(ii) Hence, determine the resultant force of the two tensions on the tworopes. State the magnitude and direction of the resultant force. [3]

Magnitude of resultant force: _______________________________

Direction of resultant force: _______________________________

2 The diagram below shows a safety valve that might be fitted to a steam-engine.

a) Calculate(i) the force, F, exerted on the valve opening by the steam, [2]

(ii) the pressure exerted by the steam on the valve opening. [2]

pivot

10 cm

80 cm

movable weight

300 N

F steam

area = 100 cm2

valve opening


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b) How would you adjust the movable weight so that the valve would releasesteam at a higher pressure? [1]

_____________________________________________________________

_____________________________________________________________

3 The graph below shows how the temperature of a pure liquid substance varied as itcools.

a) Describe what happened to the substance from

(i) A to B, [1]

_______________________________________________________

(ii) B to C, [1]

_______________________________________________________

b) Explain why the temperature of the substance remain constant as thesubstance loses energy to the surrounding from B to C. [2]

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

temperature

A

B C

D

time


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4 The diagram below shows a saucepan containing water placed on a hot plate. Aftersometime, the water becomes hot.

a) Describe and explain how heat is distributed in the water. [3]

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

b) The sides of the saucepan are often polished. Explain the advantage. [2]

_____________________________________________________________

_____________________________________________________________

5 The diagram shows a light ray traveling through water in an aquarium at an angle of40o to the surface of the water.

a) Given that the refractive index of water is 1.33, calculate the critical angle for

a ray traveling from water to air. [2]

water

steel

hot plate

plastic handle

40o

water


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b) (i) Complete the path of the light ray in the above diagram. [1]

(ii) Explain your answer. [2]

_______________________________________________________

_______________________________________________________

_______________________________________________________

_______________________________________________________

6 The diagram shows the image of an object as formed by a converging lens.

a) Complete the path of the two rays shown in the diagram above. [2]

b) Label the focal point F on the diagram above. [1]

c) Measure the focal length of the lens. [1]

_____________________________________________________________

d) The image formed is real. What is a real image? [1]

_____________________________________________________________

_____________________________________________________________

image

object

lens


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7 The diagram below shows three waves A, B and C. They travel 12.0 meters in 2.0 sthrough the same medium.

Calculate

a) the wavelength of wave A, [2]

b) the period of wave B, [1]

c) the speed of wave C. [2]


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8 A cell of e.m.f. 1.5 V was connected in series with two resistors as shown in thediagram below.

Calculate

a) the current flowing in the circuit, [2]

b) the potential difference across the 4 resistor, [1]

c) the power dissipated in the 4 resistor. [2]

1.5 V

4 6


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9 The diagram below shows an electromagnet connected to a variable resistor R, aswitch S that is open and a strong battery. A plotting compass C is placed veryclose to end B.

a) Name the material used for the core of the electromagnet. Explain youranswer. [2]

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

b) The switch S is closed. Describe and explain what would happen to thecompass needle. [2]

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

_____________________________________________________________

c) The switch S is opened again. State what would happen to the compassneedle. [1]

_____________________________________________________________

_____________________________________________________________

NN

A B

SR

core

compass

C


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SECTION B (20 MARKS)

Answer any two questions.

Write your answers on the lined pages provided and, if necessary, continue on separateanswer paper.

10 In a bungee jump, a man has both his legs bound to an elastic cord before he fallsfrom rest at a high platform. The change in the velocity of the man during the fall isrepresented by the graph below.

a) Calculate the acceleration of the man during the initial descent. [2]

b) At what time did the elastic cord first became taut? [1]

c) Calculate

(i) the deceleration of the man just before coming to rest at the firstinstance, [2]

(ii) the greatest distance moved by the man from the platform. [2]

d) Describe the main energy changes taking place as the man falls from 0.0 sto 4.0 s. [2]

e) The man finally comes to rest. State what has happen to the energy. [1]

10

20

30

40

-10

-20

-30

-40

0

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 time /s

velocity / m s-1

time / s5.0


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11 a) Illustrate with diagrams the arrangement of molecules in the solidstate, liquid state and gaseous state. [3]

b) Explain why the density of a substance is lower when it is in a gaseous statecompared to when it is a solid state. [2]

c) Describe the motion of the molecules of a substance when it is in a

(i) solid state, [1](ii) liquid state, [1](iii) gaseous state. [1]

d) Explain the effect of a rise in temperature on the motion of the molecules ofa gas. [2]

12 a) The current in a wire was measured at different voltages.The table shows the results.

Current in amperes / A 0.20 0.35 0.55 0.70 0.85Voltages in Volts / V 0.80 1.4 2.2 2.8 3.4

(i) Draw a labelled circuit diagram, which could be used in anexperiment to obtain the above data. [2]

(ii) Describe and explain what you would do with the data in order tocheck whether the wire obeys Ohms Law. [2]

b) The diagram below shows part of the lighting circuit of a house.

(i) Explain why a fuse is included in the circuit. [1]

(ii) Explain why the fuse is placed in the live wire. [2]

(iii) Each lamp has a power of 60 W.

Calculate the current through one lamp when it is switch on. [2]Hence calculate the maximum number of similar lamps that can beinstalled in this house. [1]

------------------------------------ End of Paper -----------------------------------

240 V

live

neutral

fuse 5 A


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TABLE OF SPECIFICATIONScience Physics (5116 / 5117) Sec 4 Express & 5NA Paper 2 Preliminary 2 Exam 2009

Recall Understand ApplicationTOPICS

P1 P2A P2B P1 P2A P2B P1 P2A P2B

Marks

Measurements1 1

Kinematics 4 1 3 8

Forces 1 1

Vectors 1 2 4 7

Pressure 2 2

Mass, wt & density 1 1

Turing effect of forces 1 3 4

Energy, work & power 2 1 1 4

Kinetic Model ofMatter

3 5 2 10

Transfer of thermalenergy

1 3 2 6

Thermal properties 1 4 5

Waves 1 2 3 6

Reflection

Refraction 1 2 3 6

Lens 1 1 2 2 6

Electromagneticwaves

1 1

Sound 1 1

Static Electricity 1 1

Current Electricity 1 4 5

D.C. Circuit 1 5 6

Practical Electricity 1 3 2 1 7

Magnetism 1 1

Electromagnetism 2 1 3 6

Total 7 3 8 9 20 11 4 22 11 95

Marks 18 40 37 95

Marks (%) 18.9 42.2 38.9 100%


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SOLUTIONS

Science Physics (5116/5117) Sec 4 Express & 5NA Paper Preliminary 2 Exam 2009

Paper 1

1) B 2) B 3) A 4) D 5) D6) B 7) B 8) D 9) B 10) D11) B 12) B 13) C 14) A 15) A16) C 17) A 18) A 19) D 20) D

Paper 2

1 a) (i) The two forces act opposite to each other. [1](ii) The two forces act in the same direction. [1]

b) (i) [1](ii) [1]

Magnitude of resultant force = 156 N [1]Direction of resultant force = 25o from the 140 N force [1]

(or 65o from the 64 N force)2 a) (i) Taking moment about pivot,

Sum of anticlockwise moment = sum of clockwise momentF x 10 = 300 x 80

F = 2 400 N [2]

(ii) P = F / A= 2 400 / 100= 24 Ncm-2 or 2.4 x 105 Pa [2]

b) Move the movable weight further from the pivot to the right. [1]

Rope B64 N

Rope A140 N

90o


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3 a) (i) A to B: The liquid cools down (or temperature decreases)[1]

(ii) B to C: The liquid gradually solidify at constanttemperature. [1]

b) The lost of energy will results in the formation of the intermolecularbonds among the molecules. Thus the liquid solidifies. [1]

The average KE of the molecules remain unchanged. Thus thetemperature remain unchanged. [1]

4 a) Heat is distributed by convection.The warmer water near the hot plate expands and becomes less dense.So it rises. The cooler water above is denser so it sinks. This results inthe formation of the convection current. [3]

b) Polished surface is poor emitter of infrared radiation. Thus heat lostdue to radiation is reduced. [2]

5 a) Sin C = 1 / n= 1 / 1.33

C = 48.8o [2]

b) (i) [1]

(ii) The ray undergoes total internal reflection. [1]The angle of incidence is greater than the critical angle and it isin a denser medium. [1]

6 a, b) [3]

c) Focal length = 2.1 cm [1]d) Real image is an image that can be formed on a screen. [1]

40o

water

image

object

lens

F


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7 a) wavelength of A = 12 / 4= 3.0 m [2]

b) Period of B = 2.0 s [1]c) Speed of C = d / t

= 12.0 / 2.0= 6.0 m/s [2]

8 a) I = V / R= 1.5 / (4 + 6)= 0.15 A [2]

b) V = R I= 4 x 0.15= 0.6 V [1]

c) P = V I= 0.6 x 0.15= 0.09 W [2]

9 a) Iron. [1]It is easily magnetized when current flow through the coil. [1]And easily demagnetized when the current is not flowing.

b) The needle will point to the right. [1]When current flow around the coil the core is magnetized with B asthe N-pole. The N-pole will repel the N-pole of the needle. [1]

c) The needle will remain pointing to the right. [1]

10 a) a = (v u) / t= (40 0) / 4= 10 ms-2 [2]

b) 4.0 s [1]

c) (i) a = (v u) / t= (0 40) / 1= - 40

Deceleration = 40 ms-2 [2]

(ii) distance = area under graph= x 5 x 40= 100 m [2]

d) Gravitational potential energy to kinetic energy. [2]e) The energy is given to the surrounding as heat. [1]


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11 a) [3]

b) For the same volume, the gas has smaller mass than the solid. [1]Since d = m/V, the gas has smaller density than solid. [1]

c) (i) The molecules vibrate within a fixed position [1](ii) The molecules move randomly & freely within the liquid [1](iii) The molecules move randomly, very freely & very fast [1]

d) The molecules gain kinetic energy and move faster. [2]

12 a) (i) [2]

(ii) Plot a graph of voltage against current. [1]If the graph is a straight line passing through the origin, then itobeys Ohms law. [1]

b) (i) To prevent overheating of the wires by breaking the circuit whenthe current exceeded the fuse rating. [1]

(ii) To disconnect the circuit from the high voltage live wire whenthe fuse break. Thus preventing the user from electric shock. [2]

(iii) I = P / V= 60 / 240= 0.25 A [2]

Max number of lamps = 5 / 0.25= 20 [1]

Rheostat

(variable resistor)

V

A+

+

_

_

solid liquid gas


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Markers Report

Questions that are not well answered are as follow.

2 (a) (ii) Common mistakes: wrong unit,wrong conversion of unit.

3 Common mistakes: misunderstood the question,Energy is usedto form intermolecular bondsDid not write average ke is unchanged.

4 (b) Common mistakes: Poor absorber / poor reflectorDid not write heat lost due to radiation is reduced.

5 (b) Common mistakes: Unable to see that the angle of incidence is greater thanthe critical angle.Did not write that the incident ray is in the densermedium.

9 (b) Common mistakes: Did not write N-pole repel N-pole.(c) Unale to see that the compass needle is a magnet.

kranji prelim09 5116 p2 with keys

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