physics perfect score module (answer)

1

BAHAGIAN PENGURUSAN

SEKOLAH BERASRAMA PENUH SEKOLAH KLUSTER

KEMENTERIAN PELAJARAN MALAYSIA

MARKING SCHEME

PERFECT SCORE MODULE

PHYSICS

2010

2

MODEL ANSWER PHYSICS PERFECT SCORE 2008

SECTION 1 - CONCEPTUAL

QUESTION ANSWER MARK

1

(a)(i) Weight/ air resistance 1

(ii) Acceleration 1

(b) (i) (ii) (iii)

The force in 5.1 larger than 5.2 5.1 same with 5.2 Time of impact in 5.1 shorter than 5.2

1 1 1

(c) The force produced increase when the collision time decrease 1

(d) Impulsive force

2

(a) Ice less dense than water 1

(b) Weight and Upthrust 1

(c) i Volume of water displaced in 5.1 more than 5.2 1

ii Weight of water displaced in 5.1 more than 5.2 1

iii Buoyant force in 5.1 more than 5.2 1

iv Buoyant force equal to the weight of water displaced 1

v Archimedes Principle 1

3

(a)i Contact surface area in 9.1 is smaller than in 9.2

1

(a) ii

Pain / discomfort is greater in 9.1 than 9.2 1

(a)(iii) The smaller the contact area, the grater the discomfort and the greater the pressure

1 1

(b) Pressure = force per unit area Unit : N m

-2 or Pa

1 1

4

(a) The amount of heat that is required to increase the temperatute of 1 kg substance by 1

0 C

1

(b)i 15000 = 1 x 900 x

= 16.67C

1 1

(b) ii 15000 = 1 x 390 x

= 38.46C

1

(c) The rise in temperature for metal block P is smaller than Q // vice versa 1

(d)i ii i) Specific heat capacity of metal block P is greater than Q (ii) The rise in temperature is smaller when specific heat capacity is greater

1 1

(e) Thermal equilibrium is achieved 1

5

(a) Distance between two consecutive crest 1

(b) d = 1250 x 0.15 = m 2

(c)i Amplitude of reflected waves is lower than transmited waves 1

(c)ii Some energy loss during transmission 1

(c)iii The amplitude of the reflection wave in Diagram 5.4 is higherthan 5.3 1

(c)iv 5.3 deeper than 5.4. When the depth increases, the energy lost inceases 1

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(a) same 1

(b) i M1 brighter than M1 1

ii V1 is bigger than V2 1

iii V3 = V1 +V2 1

Iv A1 = A2 + A3 1

(c) i Series circuit 1

ii Not suitable 1

If one bulb blown up ( does not light up) all the bulb will not function 1

3


7

(a) Diagram 6.1 has less number of turns compare to Diagram 6.2 1

Diagram 6.1 has less deflection of pointer compare to Diagram 6.2 1

(b) P = North Q = South 2

(c) The larger the number of turns, the higher the induced current produced. 1

(d) Faraday’s Law 1

(e) Increase the speed of the relative motion between the coil and the magnet // Use a stronger magnet

1

(f) Direct Current Generator (D.C. Dynamo) // Alternating Current Generator (A.C. Dynamo) // Moving coil microphone

1

8

i Density of glass block in 9.3 denser than 9.2 1

ii Refractive index of glass block in 9.3 more than 9.2 1

iii The angle of refraction in 9.2 more than 9.3 1

iv When the density of the glass increase the angle of refraction decrease 1

v When the refractive index increase angle of refraction decrease 1

9

(a)i Wavelength in shallow area is shorter // vice versa 1

ii when depth increase wavelength increase

(b)

(i) 1. v = 12 x 0.1 2. = 1.2 m/s (ii) v = 12 x 0.2 3. = 2.4 m/s

3

(c) Depth increase , velocity will increase too. 1

(d) Energy per unit volume is smaller in deep area 1

10

(a) A resultant field due to the combination of the magnetic field due to the current in the conductor and external magnetic field // Diagram

(b) Number of magnet in 10.2 is more than 10.1 angle of deflection of cooper wire D10.2 is bigger the angle of deflection of ammeter indicator in 10.2 is larger

3

(c) as the number of magnet used increase the strength of catapult field increase and the angle of deflection of copper wire increase.

2

11

(a) Work done in moving one unit of charge between one point to another. 1

(b)

The voltmeter in Figure 10.1(a) is parallel to the resistor while in Figure 10.2(a) the voltmeter is parallel to the battery.

1

The graph in 10.1(b) shows that potential difference is directly proportional to current

1

Obeys Ohm’s law 1

Graph in Figure 10.2(b) shows that the potential difference across the cell decreases when the current flowing through it increases.// V decreases linearly with I

1

Voltage drop is due to the internal resistance of the battery 1

12

(a) The rate of flow of charge 1

(b)

The length of the coil in Diagram 9.2 is equal to the length of the coil in Diagram 9.3 The thickness of the heating element in Diagram 9.2 is more than the thickness of the heating element in Diagram 9.3 The time taken to boil the water for kettle P is > the time taken for kettle Q The thinner the coil, the more the resistance The thinner the wire the more heat produced to boil the water

1 1 1 1 1

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(a) Semiconductors are material which can conduct electricity better than insulator but not as well as conductor

1

(b)

The input current in both diagrams is alternating current 1

The current produced by output transformer also alternating current 1

Current flow through R are direct current 1

Draw correct waveform 4

4


10.1- half waves rectification 10.2- full waves rectification

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(a) Is a spontaneous disintegration of unstable nucleus accompanied by the emission of energertic particles

(b)i Shape of the graph- Curve graph/exponential -shape 10.1 same as 10.2 Time taken for activity to become half shorter in diagram 10.2

Ii P= 5 hours Q = 100 seconds

iii Half life

SECTION 2 – PROBLEM SOLVING (QUALITATIVE) QUESTION 1 [FORCES & MOTION]

Semi circular curve shaped Exchange between kinetic energy and gravitational potential energy easily.

Increasing / decreasing slope slightly Easily oscillates caused by changing of energy

Smooth surface Easily to moves // Reduce frictional force

Soft layer at the surface Reduce impulsive force when landing / accident

Strong material // concrete of foundation of the track

Withstand to the high force caused by jumping and landing.

QUESTION 2 [FORCES & PRESSURE]

Thicker wall at the base To withstand greater pressure at the bottom as the pressure increases with depth

The wall is constructed using stronger materials / Using reinforce concrete

To avoid the wall from breaking / To increase the strength of the wall / To avoid leaking

Equipped with the water overflow system To avoid flooding / To channel away the overflow water

Increase the height of the dam Store more water

Use turbine Produce electricity

Place turbine at the bottom of the wall High water pressure can be used to turn the turbine

QUESTION 3 [HEAT]

Top insulated cap/ stopper reduce the heat loss /heat flow in through conduction // slow down the heat transfer

Vacuum region/ / space reduce the heat transfer

High specific heat capacity material as body Heat up slower

Used a strong materials as body/ Has higher strength //

Used low density of material lighter

low rate of rusting can be used for a longer time.

QUESTION 4 [LIGHT]

Use refractive index of outer layer is less than therefractive index of outer layer

So that total internal reflection can happen in the fiber optic

Use high flexibility material so that it can be bend

Use strong material do not break easily

Use thin material Lighter // can be use in small area

Low density material Lighter

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QUESTION 5 [LIGHT]

P as eye piece and Q as objective lens Focal length of P is longer

fo < u < 2fo to produce real, inverted and magnified image

Adjusted so that u < fe to produce virtual, inverted and bigger image // to acts as a magnifying glass

Distance between lenses > fo + fe To produce bigger image from the eyepiece // to increase the magnification

Store in a cool and dry place To avoid formation fungus at the lenses

QUESTION 6 [WAVES]

Distance between two stereo speakers Near to one another

To reduce interference

The speakers must be placed in front of the microphones �The speaker must be placed in front of the microphone The speaker must be placed in front of the microphone

To avoid humming/disturbance // To prevent the sound from speakers being amplified again by the microphones

Covers the walls with thick and soft curtains / a layer of soft board

To reduce the echoes effect // Soft materials can reduce reflection of sound waves

Use chairs with thick cushions To reduce the echoes effect // Soft materials can reduce reflection of sound waves

Covers the floor with thick carpets To reduce the echoes effect // Soft materials can reduce reflection of sound waves

Covers the wall with uneven/rough surface To reduce the echoes effect // So that the reflected waves are in various directions and finally being absorbed

Make sure all the small openings between doors/windows and the door/window frames are closed up

To avoid diffraction of sound waves // To avoid noise from the outside

Positioning of the two speakers and audience is arranged in the way as such that they form a triangle

To produce a clear sound staging effect

QUESTION 7 [ELECTRICITY]

Attach one fuse to the live wire in the consumer unit/ fuse box.

To break/switch off the circuit when large current before the wire become hotter and produce fire.

The speakers must be placed in front of the microphones �Using the insulating wires // thicker wires Using the insulating wires // thicker wires

To prevent short circuit // To reduce resistance, improve efficiency

Attach switch for each lamp To allows each lamp to be switched on and off independently

Connect the metal fitting lamp to the earth wire/cable

To flows electron (extra) to earth to avoid lethal shock

Using only 240 V light bulb. To ensure the bulbs light up with normal brightness

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QUESTION 8 [ELECTRICITY]

Use the fluorescent lamp Consume less power and economic

Use a more efficient fluorescent lamp It brightens the room more clearly and thoroughly and prevents wastage

Use a more energy efficient fluorescent lamp Helps the temperature in the room to be not too hot due to less energy loss in form of heat energy

Fuses should be connected to the fluorescent lamp

To prevent overheating of lamps might cause the fluorescent lamp to blow out

Two or more fluorescent lamp are arrange in parallel

If one lamp blows the rest are still functioning

QUESTION 9 [ELECTROMAGNETISM] The efficiency of the electric bell can be increased by

U shape core To increase the strength of magnetic field

Attach spring to armature The armature will return back to its original position when no attraction occur

Attach contact screw to armature Cut the circuit when the armature attract to the electromagnet, so that the hammer hit the gong continuously

Increase the number of turn of coil To increase the strength of magnetic field

Use soft iron core To increase the strength of magnetic field

QUESTION 10 [ELECTROMAGNETISM]

use thin diaphragm Easy to vibrate

Use strong material Not easy to break

More number of turns of coil Increase the rate of change of magnetic flux linkage // The magnitude of the induced current or is also increased

Thicker diameter of wire of coil reduce the resistance of the coil

Using more powerful magnet to increase the strength of the magnetic field

Increase the rate of change of magnetic flux linkage //The magnitude of the induced current or induced electromotive force is also increased

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QUESTION 11 [ELECTROMAGNETISM] The sensitivity of the moving coil galvanometer can be increased by

Use radial magnet To increase the strength of magnetic field // increase the force between the current carrying coil and magnetic field.

Use hairspring of lower stiffness smaller opposing forces to stop the turning of the coil.

Use a lighter pointer/cylinder smaller inertia, easier to move

Use a coil of lighter mass smaller inertia, able to move easily

increasing the area of the coil more changes to the magnetic flux, a bigger force is produced.

QUESTION 12 [ELECTROMAGNETISM]

Change slip rings with commutator

To reverse contact with brushes so that the current flow in same direction in external circuit

Use more number of turn for the coil/ Increase the speed of rotation

Increase the rate of change of magnetic field/increase the induced current

Use strong magnet.

Strong magnet produced strong magnetic field, when a conductor cutting through a strong magnetic field, high e.m.f./current will be induced.

Concave poles of magnet // Use radial magnet

Concave poles provide a radial field which ensures the cutting of the magnetic field is always maximum.

Larger area of coils. The larger the area of the coil, the more the magnetic field will be cut through, therefore more e.m.f./current is induced.

Wires are wound on a soft iron core which is called armature.

The armature becomes magnetized and increases the strength of the magnetic field

QUESTION 13 [ELECTRONIC]

Component Function

Filament To heat up the cathode

Cathode Emits electrons

Control Grid

Controls the number of electrons // control the brightness of the image on the screen

Focusing anode Focuses the electrons into a beam

Accelerating anode To accelerate electrons to towards the screen

Y-plates To deflect the electron beam vertically

X-plates To deflect the electron beam horizontally

QUESTION 14 [ELECTRONIC]

Replace thermistor with R1 IB / IC flow // transistor on when high temperature //

Replace R1 with thermistor Potential divider

Replace fan with relay switch To switch on the secondary circuit

Use 240V power supply at secondary circuit To supply electricity in the secondary circuit

Air conditioner at secondary circuit Connect to 240V of a.c. power supply

Diode connect parallel with relay coil To protect the transistor from being damaged by the large induced e.m.f. in the relay coil when the IC drops to zero

8

Question 15 [Electronics]

a

(i) 0111 1

(ii) 1000 1

(iii) 0001 1

(iv) 1110 1

b (i) 0001 1

(ii) AND 1

c

Q Q

1

d

R

Q

P

3

QUESTION 16 [RADIOACTIVITY]

Uses thick lead box Radioactive rays cannot pass through

Packed into concrete drum and buried underground

Prevent the radioactive waste discharged to the environment

Use forceps/ robotic hand Avoid direct touching

Use siren Faster warning when leakage

Wearing photographic films Detect the exposure radiations

6V

R1

RB

Thermistor Air conditioner

240 V a.c. power supply

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State of matter ; solid form easy to handle

beta-ray has high penetrating power/ able to penetrate through the paper

the half-life is longer Can last longer/ can use for longer period/ no need to replace frequently

high penetrating power/moderate Can penetrate the paper

Use a Geiger Muller tube as detector Can detect beta rays/ radioactive emission


The half-life should be a few days long This allows for the location to be detected and thereafter the radioactive contamination is reduced

The substance should emit γ particles

This allows the radiation to be able to be detected above the ground

The detector should be able to detect γ particles (low ionising particles) // GM tube

High ionising particles like α and β particles are absorbed by the ground

Substance in liquid state Easy to flow in the water

High penetrating power Penetrate the ground so that it can be detected by a detector

SECTION 3 – DECISION MAKING 1.

Characteristic Explanation

Smallest 0.1 cm More sensitive measuring

Range of measurement 0 – 50 cm Suitable with the size of metal block

Zero error is 0 More accurate, no zero error

Shape of instrument flat and thin Suitable with the shape of metal block

R

Smallest 0.1 cm, Range of measurement 0 – 50 cm, Zero error is 0 and Shape of instrument flat and thin

10 marks

2.


Length of the chain from the bar 210 cm

the frequency of swing oscillations will be higher

Joint of chain to the bar with ball bearing

Reduce the friction, it can rotate smoothly

Angle of V-shape pillar 40o Increase the stability, low centre of gravity

Soft padded floor Reduce the impulsive force if the children fall down

M

Length of the chain from the bar 210 cm, Joint of chain to the bar with ball bearing, Angle of V-shape pillar 40

o and Soft

padded floor.

10 marks

10

3.


Distance between seat and handle is far ( 75 cm )

The rider can bend his body to form an aerofoil shape to reduce the air resistance

Density of bicycle’s frame is small Mass of the bicycle will be smaller, lighter

Width of tyres are small ( 4 cm ) Less friction, increase the speed

With gear Gear act as a simple machine, less energy used

Z

Distance between seat and handle is far ( 75 cm ), Density of bicycle’s frame is small, Width of tyres are small ( 4 cm ) and has gear.

10 marks

4.


Boiling point is high Not easy to evaporate

Rate of thermal conductivity is high Can transfer heat easily

Viscosity is is low Can flow easily

Specific heat capacity high Can absorb more heat

P

Boiling point is high, rate of thermal conductivity is high, viscosity is low and specific heat capacity is high

10 marks

5.


Two prism are arrange with the hypotenuse surface parallel but perpendicular to each other

To ensures the final image is upright

Diameter of objective lens is large To allow more light to enter the binocular to produce bright images

Magnification is bigger To see the object clearly

The lens and prisms should be coated with anti-reflective coating

To increase light transmission and deliver a sharp image

T

Two prism are arrange with the hypotenuse surface parallel but perpendicular to each other, diameter of objective lens large, magnification is bigger and the lens and prisms should be coated with anti-reflective coating

10 marks

6.


The shape of the wall is thicker at the base To withstand higher pressure at deeper position

Material of wall is concrete Strong to withstand stronger wave

Location of harbour is at the bay At the bay the sea is more calmer

The wall has opening The diffraction of waves will be occur, the amplitude of waves become shorter

S

The shape of the wall is thicker at the base, material of wall is concrete, the location of harbour is at the bay and the wall has opening

10 marks

11

7.


Shape of heating element is like kettle Q or S More resistance

Melting point is high Can withstand ( not melt ) at high temperature

Ability to break at high temperature is hard Not easy to break at higher temperature

Oxidisation at high temperature is low Not easy to become oxide.

Q

The shape of the heating element is like kettle Q or S, melting point is high, ability to break at high temperature is hard and oxidisation at high temperature is low

10 marks

8.

Reason

Type of electromagnet Soft iron core (1M) - Soft iron core focused the magnetic flux / increase the strength of the electromagnet (1M)

Power supply 6V V = IR = 160 X 10-3 X 20 (1M) = 3.2 V (1M)

Terminal AB must be connected to 6V power supply (1M)

Current flow in electric motor

I = P / V = 1000 / 240 (1M) = 4.167 V (1M)

Suitable connecting wire

Thick copper wire (1M)

Copper – low resistance (1M) Thick – do not melt due to high current / low resistance (1M)

10 marks

9.


W – DC power supply with A is terminal positive and B is terminal negative

npn transistor

X – thermistor To detect the changes in temperature

Y – Fixed resistor Together with component X act as a potential divider

Z – Electromagnetic relay To switch on the second circuit (motor)

B

W – DC power supply with A is terminal positive and B is terminal negative, X – thermistor, Y – Fixed resistor and Z – Electromagnetic relay

10 marks

10.


Solubility in water is high Easy to dissolve in water

Half life is 8 days Half life of 8 15 hours is a sufficient time for the worker to detect the leakage.

Type of radiation is beta Has medium penetration power

Physical state is liquid It easy to flow in water

W

Solubility in water is high, half life is 8 days, type of radiation is beta and the physical state is liquid.

10 marks

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SECTION 4 (UNDERSTANDING) 1. 1. When the lawn mower is pushed

2. Downward force = W + Fy , so the lawn mower feels heavier 3. When the lawn mower is pulled 4. Downward force = W – Fy , so the lawn mower feels lighter

2. 1. There are two types of force; attraction and repulsive force between the particles of the solid.

2. When the solid is stretched, the molecules displaced away from each other 3. Attractive forces are acting to oppose the stretching 4. When the solid is compressed, the molecules displaced closer to each other 5. Repulsive forces are acting to oppose the compression 3. 1. The balloon acted by two forces: Upthrust and the weight of the balloon

2. The density of helium gas is less than the density of surrounding air 3. Upthrust equals to the weight of the air displaced by the ballloon 4. Upthrust is higher than the weight of the balloon

4. 1. Volume of air displaced equal to volume of a balloon

2. Density of air decreased as a altitude increase 3. Weight of displaced air become smaller 4. At certain height weight of displaced air equal to weight of the balloon

5. 1. The speed of air in the region between both vehicles is high.

2. According to Bernoulli’s principle, the pressure in the region between both

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vehicles will decrease. 3. The pressure on the rear sides of the vehicles is higher than the pressure in the region between both vehicles. 4. Both vehicles will move closer to each other.

6. 1. When the brake is pressed ,a force is applied to the piston and pressure is exerted.

2. Pressure is transmitted uniformly throughout the brake fluid. 3. Force is exerted on the piston of the brake pads 4. Brake pads will press against the brake discs.

7. 1. Molecules moving freely in random motion

2. When temperature increase, kinetic energy//velocity increase 3. Molecules strike the walls of pressure cooker more frequently,

the rate of change of momentum increase 4. Force exerted on the walls increase, pressure (P = F/A) increase

8. 1. With cover, the water vapour is trapped.

2. The water vapour will condensed 3. Releases latent heat of vaporization to the food

9. (i) 1. Temperature of the coolant decreases

2. Speed of the molecules decreases 3. Distance between molecules decreases

(ii) 1. When coolant changes from a liquid to a gas, latent heat is required. 2. Latent heat is obtained from the interior of the refrigerator.

10. 1. The convex lens is aimed/focused to a distant object (infinity)

2. The screen is adjusted until a sharp image is formed on the screen 3.The distance between the screen and the lens is measuredl 4.Focal length = distance between the screen and the lens

11. 1. The layers of air nearer the road warmer. The density of air decrease nearer to the road surface.

2. The light travel from denser to less dense area. 3. The light refract away from the normal 4. When the angle of incidence exceed the critical angle, total internal reflection occurs

12. 1. At the centre of the ocean the water waves travel at uniform speed as the depth of the sea is uniform 2. When the waves reach the coast ,the water is shallower, 3. Wave speed reduced, refraction occurs 4. Refraction causes the wave front bend toward the normal This results the wavefront following the shape of of coastline 13. 1. When a tuning fork vibrates, air molecules will vibrate.

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2. When the tuning fork moves forwards, the air is compressed. 3. When the tuning fork moves backwards, the air layers are pulled apart and cause a rarefraction. 4. Therefore, a series of compression and rarefactions will produce sound.

14. 1. Charges on the disc neutralize the negative charges on the ping pong ball

2. Likes charges on the disc and the ball repelled each other 3. The ball attracted by the positively charged disc 4. The ball oscillates between the two plates

15. .(Nichrome wire is widely used as a heating filament because)

1. Nichrome wire is an alloy 2. with low rate of oxidation 3. its resistance does not vary with temperature. (tungsten wire is more preferred as heating filament in the light bulb because ) 4. The melting point of tungsten is higher than nichrome.

16. 1. The two dry cells are connected in parallel

2. The effective e.m.f. remains the same 3. The effective internal resistance of the two cells is smaller 4. A larger current will flow through the bulb to make it brighter

17. 1. The direction of the magnetic field on the left coil is anti clockwise

2. The direction of the magnetic field on the right coil is clockwise

3. As the result the magnetic fields in the middle of the coil are in the same direction, ie upward. So the magnetic field will be stronger in the middle.

18. 1. rotate the coil in clock wise direction

2. the coil cut across the magnetic field 3. current is induced in the coil 4. the commutator change the direction in the coil so that the direction of current in external circuit I always the same.

19. 1. The (magnadur) magnets produce a magnetic field / diagram

2. The current in the wire produces a magnetic field / diagram 3. The two magnetic fields interact/combine to form a resultant / catapult field / diagram

4.

S N

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20. 1. Diode forward biased / diagram p-type to positive of battery, n-type to negative of battery

2. Electron from p-type pulled across p-n junction / p-n junction narrowed / resistance decreases , current flow in the circuit 3. Diode reverse biased / diagram p-type to negative of battery, n-type to negative of battery 4. Both electrons and holes pulled away from p-n junction / p-n junction widened / resistance increases, no current flow

21. 1. The cathode is heated and emits electrons

2. The electron/cathode ray accelerated 3. Cathode rays travel in a straight line. 4. Cathode rays is blocked by maltase cross 5. Cathode rays carry kinetic energy and converts to light energy when they hit the screen.

22. 1. Put the radioactive source opposite the detector

2. Detector is connected to the thickness indicator 3. Detector detect the reading of the changes in counts 4. If the reading of the detector is less than the specified value, the thickness of the paper is too tick / vice versa

16

SECTION 5 : PROBLEM SOLVING ( QUANTITATIVE)


1 (a) 31.25 m

(b) 5 s

2 (a) 1600 m

(b) 2.67 ms-1

3

(a) 5 ms-2

(b) 6000 N

(c) 40 m

4 (a)

The spring constant = gradient of the graph For P , spring constant = 8 / 0.5 = 16 N cm

-1

For Q , spring constant = 3 / 0.5 = 6 Ncm-1

3

(b) Elastic potential energy = ½ x 8 x 0.5 x 10 -2

=0.02 J 2

5

(a) 50 kg

(b) 50 kg

(c) 65 kg

6 (a) 2000J

(b) 3000 J

7

(i)

v2 = u

2 + 2as

0 = u2 + 2(-10)(5)

u = 10 m s-1

or ½ mv2 = mgh

v2 = 2 gh

v = 10 m s-1

2

(ii) E = ½ mv

2

= ½ ( 100/1000) (10)2

= 5 J

2

(iii) ½ kx2 = 5 J

k = 1000 N m-1

1

8

(i) Px = Fx / Ax = 15 N / 0.02 m2

= 750 Nm-2

2

(ii) F = PA = (750)(0.28) = 210 N

2

(iii)

Volume of liquid transferred is unchanged A2 x2 = A1 x1 x2 = ( A1 / A2)(x1) = (0.02 / 0.28) (21)

= 1.5 cm

2

9 (a) 1.05 x 10

7 J

(b) 3500 s

10 61200 J

11 84400 J

12 (i) u = 10 cm v/u = 2 , v = 2u v = 2x10 = 20 cm

2

(ii) v = -20 cm

17


1 = 1 + 1 f v u 1 = -1 + 1 f 20 10 f = 20 cm

2

(i) u = 10 cm v/u = 2 , v = 2u v = 2x10 = 20 cm

2

13 (i) Convex Image formed on the screen (real)

1

1

(ii)

u + v = 60 cm v = 2u

1 = 1 + 1 f u v 1 = 1 + 1 f 20 40 f = 13 cm

1

1

1

14

(a) 35.2o

(b) 41.8o

(c) At KL, angle of incidence > critical angle. Therefore total internal reflection occurs.

The light ray then travels to LM. At LM, the angle of incidence < the critical angle.

The light ray emerges

15

(i) Useful energy output =0 .8 x 10 x1.5 =12 Joule

2

(ii) Energy input = Pt = 1.2 x 5 x 4 = 24 J

2

(iii) Efficiency = 12/24 x 100 % = 50 %

2

16 (i) I =

12

10

= 0.83 A (with unit)

2

(ii)

PI = 10080

10x

= 12.5 W

I = 240

5.12/ 0.052 A (accept e.c.f)

3

17 (i) Potential difference across P = 3500 x 6 = 2.2 V (3500 + 6000)

2

(ii) Potential difference across Q, 6000 x 6 = 3.8 V (3500 + 6000)

2

(iii) Ring because the voltage across Q exceed / greater than 3.2 V.

2

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SECTION 6 – DESIGN EXPERIMENT

Q Experiment Manipulated

Variable Responding

Variable Fixed

Variable Topic

1 Mass of water and rise in temperature

Mass of water

Rise in temperature/ Final temperature

Time to heat up the water

Heat

2 Height of magnet and induced current

Height of magnet

Current Number of coil

Induced Current

3 Mass and volume of water displaced

Mass of sand Depth of straw sink

Density of water Hydrometer

4 velocity and current velocity Current induced Number of turns Electromagnets

5 Volume and pressure Volume Pressure Temperature Boyle”s Law

6 Weight and volume of liquid displaced

weight volume of liquid displaced

Density of the liquid

Force and pressure

7 Current and electromagnetic strength

Current Number of pin attract

Number of turn of solenoid

Electromagnetic effect

8 Density of water and volume of water displaced

Mass of salt dissolved in water

Depth of straw sink

Mass of straw Buoyant Force

9 Density of water and pressure

Mass of salt dissolved in water

Different depth of water level

Depth of thistle funnel

Pressure in liquid

10 Volume of water displaced and buoyant force

Depth of rod sink in water

Apparent weight

Density of water Buoyant Force

11 Length of wire and resistance

Length of wire Resistance

Thickness of wire Electricity

12 Resistance and temperature Temperature

Resistance Length of wire / thickness of wire

Electricity

13 Depth and pressure depth pressure Density of liquid electric