Paper 2

1 (a) Potential difference 1B 0.2 V 1C Zero error / parallax error 1D To prevent parallax error// to ensure that the observer takes readings from the

correct position1

2 a) Conservation of momentum 1B (m1+m2)v = m1u

V= 7.62 ms-1

2

c) The skateboard mover faster/ at a higher velocity. The momentum of the skateboard increases caused by the change in momentum of the boy in the opposite direction.

2

d) The boy may fall down because he cannot stop immediately. He tends to continue his forward motion at the same velocity due to his inertia

2

3 a) i)

Electromagnetic induction is the production of an e.m.f. across a conductor when there is a changing magnetic flux.

1

ii) Moves to and fro about the zero reading 1Iii) 1

B When the magnets are removed, no induced current produced.Although there is no catapult force produced to oppose the motion of the pendulum again, because of inertia, the pendulum continues to oscillate until the energy.

111

4. a) The marking in the fluorescent lamp indicates that it will normally use 36 J of energy per second when it is connected to a 240 V power supply.

1

b) i) Water heater 1ii) The water heater has the highest power rating 1c) E = Pt = 26x 5x 60 = 10800 J 2d) i) P = IV

I = 3000/240 = 12.5 A2

II) P = V2/ R R= V2/ P = 19.2 Ω

2

5 a) Time taken for the number of undecayed nuclei to be reduced to half of its original number.

1

b) Sodium – 24. Because the half life of the radioisotope used is short. 2c) i) same 1

ii) x = 140 y = 38

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d) Radiation workers must wear gloves when handling radioactive materials/Laboratory coat must be worn.

11

6 a) i the force per unit area exerted against a surface by the weight of the air above 1

that surface.ii) When the steam or the hot water vapour inside the cup condenses, the air

pressure inside decreases.The air pressure is much greater outside than inside the cup.Thus, a force due to the pressure difference acts on the cup making it more difficult to be lifted up.

1

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b)i) The pressure variation = 1040 – 976 mbar = 64 mbar = 64000 N m-2

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c)i) This indicates strong winds. 1Winds blow from high pressure regions to low pressure regions. 1

7.(a) Energy required to increase the temperature of a kg substance by a 1 degree Celcius.

1

b) The specific heat capacity of clay pan is greater. 1Same 1The increase of temperature of copper pan is higher than clay pan. 1

c) The higher the specific heat capacity, the lower the increase of temperature. 1d) During the day, the sun heats up both the ocean surface and the land.

Water has greater specific heat capacity and heats up much more slowly than land. The air above the land will be warmer. and will rise throughout the day.

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8 a) i)

To collect more light from the object in order to produce a brighter image.1

Fo = + 50 cmFe = 5 cmLength of the telescope = fo + fe = 55 cm

1

2iii) The telescope is too long and inconvenient.

he image formed is inverted. 114

(iv) Total internal reflection 1

Section b9) a) i)

Density is distribution of mass per unit volume of a substance1

ii) Density of air in Diagram 7.1 is greater than density of air in Diagram 7.2

The number of load in Diagram 7.1 is greater than in 7.2 The height of the balloons in both Diagram 7.1 and Diagram 7.2 are

equal. Buoyant force increases as density of air increases Weight of load carries up increases as density of air increases

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b By Archimedes principle, the buoyant force = weight of water displaced by the ship = submerged volume x density of water x gravitational field strength.

River water has a lower density than that of seawater. The buoyant force on the ship is smaller. To produce a buoyant force which equals its total weight, the ship has to

displace more river water by submerging deeper into water.

1

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Suggested modification ReasonThe ship is fitted with ballast tanks on both sides

The ballast tanks enable the ship to float when empty and sink when filled with water.

The whole body of the ship is made watertight

To prevent water from entering the ship when it is submerged.

The whole body of the ship is made stronger

Able to withstand high water pressure when it is submerged.

The body of the ship is streamline

Able to move quickly and easily through water.

The ship is fitted with a larger and more powerful propeller

To produce a larger thrust for driving the ship against strong opposing forces through water.

10

10. a)

The maximum displacement from equilibrium position1

b) The diameter of string P is greater than the diameter of string Q. The frequency of oscillation in Diagram 8.2 is less than that in Diagram 8.3. The amplitude of waves produced are the same. The greater the diameter, the less the frequency of sound wave. The greater the frequency, the greater the pitch of the sound.

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c) i) When the string is plucked, the string will vibrate. The vibration from the strings is transferred (through the bridge) to the body of the violin. The body of the violin that is a hollow chamber that vibrates the air particles and produce sound waves.

11

2

ii) Suggested modification ExplanationLow density of string//. Higher elasticity.

Low mass.// Easy to vibrate 10

High tension of string Can produce high frequencyNickel / strong material Can withstand bigger force/ /no

easily breakSound hole must be big More air can be trapped// the

coupled resonance of the front and back plates produces a resonance

The bow must be made from strong material // the bow must be sticky

No easily break.// to create friction between the bow and the strings.

11. a)

Rate of change of momentum1

b) i) Inertia causes body to lurch forward.Seat belt prevents the body from lurching forward.

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ii) Seat belt has bigger surface area.Reduce pressure on body.

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c)characteristics ReasonSmaller mass Less force acting on headWhite and shiny surface of helmet To reflect the lightExternal part of helmet is strong and rigid

Does not break and change shape

Coated with light and soft material Reduce impulsive force on headS. Small mass, White and shiny surface, light and soft and strong and rigid.

10

Ft = mv- mu= 1500 ( -35- 40)= 112500 Ns

21

Impulsive force = 112500

0.2 = 562500 N

2

12 a) Diagram 11.1, the n end of diode is connected to negative terminal of dry cell

Diagram 11.2, the n end of diode is connected to positive terminal of dry cell

Bulb in Diagram 11.1 lights up No current flow in Diagram 11.2 // Current flow in Diagram 10.1 The bulb will lights up when the p end of diode is connected to the

positive terminal of dry cell. Current only flow in the circuit when p end of diode is connected to

positive terminal of dry cell or in forward bias

1

1

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1

b) characteristic ExplanationStep – down transformer Capable of reducing potential

differenceRatio 20 : 1 Reduce potential difference 240 V

to 12 VUsing 4 diodes Full wave rectificationUsing capacitor Smoothen output currents Step down transformer, ratio is 20 :

1, using 4 diodes and using a capacitor.

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c) i) 12 V 1

ii) Pi = VI = (240)(0.5) = 120 W 1

PO = 24 + 24 = 48 W Efficiency = PO = 48 x 100% Pi 120 = 40 %

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Paper 3

No.1 a) (i) The length, l of the wire X (ii) The angle, θ (iii) The distance from A to the needle // the diameter

of the wire //the material of wire X b Values of θ are correct

(All values are correct : 2M) (One value incorrect : 1M) Tabulate l and θ correctly in the table. A Shows a table which have l , and θ B State the correct unit of l /cm and θ /° C All values of l are correct D Values of l and θ are consistent

l / cm Θ / o

50.0 3640.0 3030.0 2120.0 1610.0 9

C Draw the graph of θ against l . A - Label y-axis and x-axis correctly B - States the unit at the axis correctly C - Both axes with the even and uniform scale:

D - 5 points correctly plotted: E - a smooth best straight line

F - minimum size of the graph is 5 x 4 squares of 2 x 2 cm. d State the correct relationship based on the candidate’s

graph l is directly propotional to θ // l is increasing linearly to θ

e 1- The eye’s of observer must be perpendicular to the scale reading in order to avoid the parallax error. 2- Repeat the experiment and find the average.

2 a) (i) Ө increases linearly as t(ii) extend the line to intercept the Ө axisӨ = 27.30C

(iii) suitable big Δ drawnk = 1.75 oC/ min = 0.0292 oC s-1

B (i) substitution of mSubstitution of k c = 4. 29 X 10 3 J kg-1 o C-1

(II)Same c) - the liquid must b stirred throughout the experiment

- stay away from windSection B:

3(a)

1 State a suitable inferenceThe volume of gas depend on its temperature

(b) 1 State a relevant hypothesis .The volume of gas increases as its temperature increases

(c) 1 State the aim of experiment To investigate the relationship between the volume of gas and its temperature.

1 State the manipulated variable and the responding variable

Manipulated : TemperatureResponding : The volume of gas

1 State ONE variable that kept constantMass of gas

1 Complete list of apparatus and materialsCapillary tube, thermometer, water, metre rule and sulphuric acid

1 Arrangement of apparatus :

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State the method of controlling the manipulated variable1. Apparatus is set as shown in the above figure.2. Water is heated to 300C.

State the method of measuring the responding variable3. The vertical column of trapped air is measured by using metre rule.

Repeat the experiment at least 4 times4. The experiment is repeated using the temperature 400C, 500C, 600C

and 700C.1 Tabulation of data:

Temperature Volume of gas

1 Analyse the data . Volume of gas

Temperature

4(a)

1 State a suitable inferenceThe length of wire influences the resistance

(b) 1 State a relevant hypothesis . When the length of wire increases, the resistance also increases.

(c) 1 State the aim of experiment To determine the relationship between the length of wire, l withresistance, R.

1 State the manipulated variable and the responding variable

Manipulated : length of wire,lResponding : resistance, R

1 State ONE variable that kept constantDiameter of wire

1 Complete list of apparatus and materialsmetre rule, voltmeter, ammeter, dry cell, rheostat, constantan wire

1 Arrangement of apparatus :

1

1

1

State the method of controlling the manipulated variableApparatus is set as shown in the above diagramMeasure length of wire, l = 20.0 cm with a metre-ruleState the method of measuring the responding variableAdjust the rheostate so that current, I = 0.01 A throughout theexperiment.Use current with smaller value so that the temperature of the constantanwire is constant.Calculate the resistance, R =I/VVoltage, V is obtained from the voltmeterCurrent, I is obtained from the ammeterRepeat the experiment at least 4 timesRepeat the experiment with l = 40.0 cm, 60.0 cm, 80.0 cm, 100.00 cm

1 Tabulation of data:L ( cm) V (V) I (A) R ()

20.0 0.01

40.0 0.01

60.0 0.01

80.0 0.01

100.0 0.01

1 Analyse the data . R ()