physics perfect score module (answer)

of 18/18
1 BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH SEKOLAH KLUSTER KEMENTERIAN PELAJARAN MALAYSIA MARKING SCHEME PERFECT SCORE MODULE PHYSICS 2010

Post on 04-Oct-2014

435 views

Category:

Documents

15 download

Embed Size (px)

TRANSCRIPT

BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH SEKOLAH KLUSTER KEMENTERIAN PELAJARAN MALAYSIA

MARKING SCHEMEPERFECT SCORE MODULE

PHYSICS

2010

1

MODEL ANSWER PHYSICS PERFECT SCORE 2008SECTION 1 - CONCEPTUAL QUESTION (a)(i) (ii) (b) (i) (ii) (iii) (c) (d) (a) (b) (c) i ii iii iv v (a)i ANSWER Weight/ air resistance Acceleration 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 The force produced increase when the collision time decrease Impulsive force Ice less dense than water Weight and Upthrust Volume of water displaced in 5.1 more than 5.2 Weight of water displaced in 5.1 more than 5.2 Buoyant force in 5.1 more than 5.2 Buoyant force equal to the weight of water displaced Archimedes Principle Contact surface area in 9.1 is smaller than in 9.2 MARK 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1

1

2

3

4

5

6

(a) i Pain / discomfort is greater in 9.1 than 9.2 i The smaller the contact area, the grater the discomfort and the (a)(iii) greater the pressure Pressure = force per unit area (b) -2 Unit : N m or Pa The amount of heat that is required to increase the temperatute of 1 kg (a) 0 substance by 1 C 15000 = 1 x 900 x (b)i = 16.67C 15000 = 1 x 390 x (b) ii = 38.46C (c) The rise in temperature for metal block P is smaller than Q // vice versa i) Specific heat capacity of metal block P is greater than Q (d)i ii (ii) The rise in temperature is smaller when specific heat capacity is greater (e) Thermal equilibrium is achieved (a) Distance between two consecutive crest (b) d = 1250 x 0.15 = m (c)i Amplitude of reflected waves is lower than transmited waves (c)ii Some energy loss during transmission (c)iii The amplitude of the reflection wave in Diagram 5.4 is higherthan 5.3 (c)iv 5.3 deeper than 5.4. When the depth increases, the energy lost inceases (a) same (b) i M1 brighter than M1 ii V1 is bigger than V2 iii V3 = V1 +V2 Iv A1 = A2 + A3 (c) i Series circuit Not suitable ii If one bulb blown up ( does not light up) all the bulb will not function

2

QUESTION (a) (b) (c) (d) (e) (f) i ii iii iv v (a)i ii (b) (c) (d) (a) 10

ANSWER Diagram 6.1 has less number of turns compare to Diagram 6.2 Diagram 6.1 has less deflection of pointer compare to Diagram 6.2 P = North Q = South The larger the number of turns, the higher the induced current produced. Faradays Law Increase the speed of the relative motion between the coil and the magnet // Use a stronger magnet Direct Current Generator (D.C. Dynamo) // Alternating Current Generator (A.C. Dynamo) // Moving coil microphone Density of glass block in 9.3 denser than 9.2 Refractive index of glass block in 9.3 more than 9.2 The angle of refraction in 9.2 more than 9.3 When the density of the glass increase the angle of refraction decrease When the refractive index increase angle of refraction decrease Wavelength in shallow area is shorter // vice versa when depth increase wavelength increase (i) 1. v = 12 x 0.1 2. = 1.2 m/s (ii) v = 12 x 0.2 3. = 2.4 m/s Depth increase , velocity will increase too. Energy per unit volume is smaller in deep area A resultant field due to the combination of the magnetic field due to the current in the conductor and external magnetic field // Diagram 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 as the number of magnet used increase the strength of catapult field increase and the angle of deflection of copper wire increase. Work done in moving one unit of charge between one point to another. 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. The graph in 10.1(b) shows that potential difference is directly proportional to current Obeys Ohms law 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 Voltage drop is due to the internal resistance of the battery The rate of flow of charge 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 Semiconductors are material which can conduct electricity better than insulator but not as well as conductor The input current in both diagrams is alternating current The current produced by output transformer also alternating current Current flow through R are direct current Draw correct waveform

MARK 1 1 2 1 1 1 1 1 1 1 1 1 1 3

7

8

9

1 1

3

(b) (c) (a)

2 1 1 1 1 1

11

(b)

1 1 1 1 1 1 1 1 1 1 1 4 3

(a)

12

(b)

(a) 14 (b)

QUESTION

ANSWER 10.1- half waves rectification 10.2- full waves rectification Is a spontaneous disintegration of unstable nucleus accompanied by the emission of energertic particles 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 P= 5 hours Q = 100 seconds Half life

MARK

(a) 15 (b)i Ii iii

SECTION 2 PROBLEM SOLVING (QUALITATIVE)QUESTION 1 [FORCES & MOTION] Semi circular curve shaped Increasing / decreasing slope slightly Smooth surface Soft layer at the surface Strong material // concrete of foundation of the track Exchange between kinetic energy and gravitational potential energy easily. Easily oscillates caused by changing of energy Easily to moves // Reduce frictional force Reduce impulsive force when landing / accident Withstand to the high force caused by jumping and landing.

QUESTION 2 [FORCES & PRESSURE] Thicker wall at the base The wall is constructed using stronger materials / Using reinforce concrete Equipped with the water overflow system Increase the height of the dam Use turbine Place turbine at the bottom of the wall To withstand greater pressure at the bottom as the pressure increases with depth To avoid the wall from breaking / To increase the strength of the wall / To avoid leaking To avoid flooding / To channel away the overflow water Store more water Produce electricity High water pressure can be used to turn the turbine

QUESTION 3 [HEAT] Top insulated cap/ stopper Vacuum region/ / space High specific heat capacity material as body Used a strong materials as body/ Used low density of material low rate of rusting reduce the heat loss /heat flow in through conduction // slow down the heat transfer reduce the heat transfer Heat up slower Has higher strength // lighter can be used for a longer time.

QUESTION 4 [LIGHT] Use refractive index of outer layer is less than therefractive index of outer layer Use high flexibility material Use strong material Use thin material Low density material So that total internal reflection can happen in the fiber optic so that it can be bend do not break easily Lighter // can be use in small area Lighter

4

QUESTION 5 [LIGHT] P as eye piece and Q as objective lens fo < u < 2fo Adjusted so that u < fe Distance between lenses > fo + fe Store in a cool and dry place Focal length of P is longer to produce real, inverted and magnified image to produce virtual, inverted and bigger image // to acts as a magnifying glass To produce bigger image from the eyepiece // to increase the magnification To avoid formation fungus at the lenses

QUESTION 6 [WAVES] Distance between two stereo speakers Near to one another 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 Covers the walls with thick and soft curtains / a layer of soft board Use chairs with thick cushions Covers the floor with thick carpets Covers the wall with uneven/rough surface Make sure all the small openings between doors/windows and the door/window frames are closed up Positioning of the two speakers and audience is arranged in the way as such that they form a triangle To reduce interference To avoid humming/disturbance // To prevent the sound from speakers being amplified again by the microphones To reduce the echoes effect // Soft materials can reduce reflection of sound waves To reduce the echoes effect // Soft materials can reduce reflection of sound waves To reduce the echoes effect // Soft materials can reduce reflection of sound waves To reduce the echoes effect // So that the reflected waves are in various directions and finally being absorbed To avoid diffraction of sound waves // To avoid noise from the outside To produce a clear sound staging effect

QUESTION 7 [ELECTRICITY] Attach one fuse to the live wire in the consumer unit/ fuse box. The speakers must be placed in front of the microphones Using the insulating wires // thicker wires Using the insulating wires // thicker wires Attach switch for each lamp Connect the metal fitting lamp to the earth wire/cable Using only 240 V light bulb. To break/switch off the circuit when large current before the wire become hotter and produce fire. To prevent short circuit // To reduce resistance, improve efficiency To allows each lamp to be switched on and off independently To flows electron (extra) to earth to avoid lethal shock To ensure the bulbs light up with normal brightness

5

QUESTION 8 [ELECTRICITY] Use the fluorescent lamp Use a more efficient fluorescent lamp Use a more energy efficient fluorescent lamp Fuses should be connected to the fluorescent lamp Two or more fluorescent lamp are arrange in parallel Consume less power and economic It brightens the room more clearly and thoroughly and prevents wastage Helps the temperature in the room to be not too hot due to less energy loss in form of heat energy To prevent overheating of lamps might cause the fluorescent lamp to blow out 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 The armature will return back to its original position Attach spring to armature when no attraction occur Cut the circuit when the armature attract to the Attach contact screw to armature 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 Use strong material More number of turns of coil Thicker diameter of wire of coil Using more powerful magnet to increase the strength of the magnetic field Easy to vibrate Not easy to break Increase the rate of change of magnetic flux linkage // The magnitude of the induced current or is also increased reduce the resistance of the coil Increase the rate of change of magnetic flux linkage //The magnitude of the induced current or induced electromotive force is also increased

6

QUESTION 11 [ELECTROMAGNETISM] The sensitivity of the moving coil galvanometer can be increased by To increase the strength of magnetic field // increase the force between the current carrying coil and magnetic field. smaller opposing forces to stop the turning of the coil. smaller inertia, easier to move smaller inertia, able to move easily more changes to the magnetic flux, a bigger force is produced.

Use radial magnet Use hairspring of lower stiffness Use a lighter pointer/cylinder Use a coil of lighter mass increasing the area of the coil

QUESTION 12 [ELECTROMAGNETISM] Change slip rings with commutator Use more number of turn for the coil/ Increase the speed of rotation Use strong magnet. To reverse contact with brushes so that the current flow in same direction in external circuit Increase the rate of change of magnetic field/increase the induced current 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 provide a radial field which ensures the cutting of the magnetic field is always maximum. The larger the area of the coil, the more the magnetic field will be cut through, therefore more e.m.f./current is induced. The armature becomes magnetized and increases the strength of the magnetic field

Concave poles of magnet // Use radial magnet Larger area of coils. Wires are wound on a soft iron core which is called armature.

QUESTION 13 [ELECTRONIC] Component Filament Cathode Control Grid Focusing anode Accelerating anode Y-plates X-plates Function To heat up the cathode Emits electrons Controls the number of electrons // control the brightness of the image on the screen Focuses the electrons into a beam To accelerate electrons to towards the screen To deflect the electron beam vertically To deflect the electron beam horizontally

QUESTION 14 [ELECTRONIC] Replace thermistor with R1 Replace R1 with thermistor Replace fan with relay switch Use 240V power supply at secondary circuit Air conditioner at secondary circuit Diode connect parallel with relay coil IB / IC flow // transistor on when high temperature // Potential divider To switch on the secondary circuit To supply electricity in the secondary circuit Connect to 240V of a.c. power supply To protect the transistor from being damaged by the large induced e.m.f. in the relay coil when the IC drops to zero

7

Thermistor

Air conditioner

240 V a.c. power supply RB R1

6V

Question 15 [Electronics] (i) (ii) (iii) (iv) (i) (ii) 0111 1000 0001 1110 0001 AND 1 1 1 1 1 1

a

b

c

Q

Q

1

Q

dR

P

3

QUESTION 16 [RADIOACTIVITY] Uses thick lead box Packed into concrete drum and buried underground Use forceps/ robotic hand Use siren Wearing photographic films Radioactive rays cannot pass through Prevent the radioactive waste discharged to the environment Avoid direct touching Faster warning when leakage Detect the exposure radiations

8

QUESTION 16 [RADIOACTIVITY] State of matter ; solid form beta-ray the half-life is longer high penetrating power/moderate Use a Geiger Muller tube as detector easy to handle has high penetrating power/ able to penetrate through the paper Can last longer/ can use for longer period/ no need to replace frequently Can penetrate the paper Can detect beta rays/ radioactive emission

QUESTION 20 [RADIOACTIVITY] The half-life should be a few days long The substance should emit particles The detector should be able to detect particles (low ionising particles) // GM tube Substance in liquid state High penetrating power This allows for the location to be detected and thereafter the radioactive contamination is reduced This allows the radiation to be able to be detected above the ground High ionising particles like and particles are absorbed by the ground Easy to flow in the water Penetrate the ground so that it can be detected by a detector

SECTION 3 DECISION MAKING1. Characteristic Smallest 0.1 cm Range of measurement 0 50 cm Zero error is 0 Shape of instrument flat and thin R Explanation More sensitive measuring Suitable with the size of metal block More accurate, no zero error Suitable with the shape of metal block Smallest 0.1 cm, Range of measurement 0 50 cm, Zero error is 0 and Shape of instrument flat and thin 10 marks

2. Characteristic Length of the chain from the bar 210 cm Joint of chain to the bar with ball bearing o Angle of V-shape pillar 40 Soft padded floor M Explanation the frequency of swing oscillations will be higher Reduce the friction, it can rotate smoothly Increase the stability, low centre of gravity Reduce the impulsive force if the children fall down Length of the chain from the bar 210 cm, Joint of chain to the o bar with ball bearing, Angle of V-shape pillar 40 and Soft padded floor. 10 marks

9

3. Characteristic Distance between seat and handle is far ( 75 cm ) Density of bicycles frame is small Width of tyres are small ( 4 cm ) With gear Z Explanation The rider can bend his body to form an aerofoil shape to reduce the air resistance Mass of the bicycle will be smaller, lighter Less friction, increase the speed Gear act as a simple machine, less energy used Distance between seat and handle is far ( 75 cm ), Density of bicycles frame is small, Width of tyres are small ( 4 cm ) and has gear. 10 marks

4. Characteristic Boiling point is high Rate of thermal conductivity is high Viscosity is is low Specific heat capacity high P Explanation Not easy to evaporate Can transfer heat easily Can flow easily Can absorb more heat Boiling point is high, rate of thermal conductivity is high, viscosity is low and specific heat capacity is high 10 marks

5. Characteristic Two prism are arrange with the hypotenuse surface parallel but perpendicular to each other Diameter of objective lens is large Magnification is bigger The lens and prisms should be coated with anti-reflective coating Explanation To ensures the final image is upright

To allow more light to enter the binocular to produce bright images To see the object clearly To increase light transmission and deliver a sharp image 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

T

6. Characteristic The shape of the wall is thicker at the base Material of wall is concrete Location of harbour is at the bay The wall has opening Explanation To withstand higher pressure at deeper position Strong to withstand stronger wave At the bay the sea is more calmer The diffraction of waves will be occur, the amplitude of waves become shorter 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

S

10

7. Characteristic Shape of heating element is like kettle Q or S Melting point is high Ability to break at high temperature is hard Oxidisation at high temperature is low Q Explanation More resistance Can withstand ( not melt ) at high temperature Not easy to break at higher temperature Not easy to become oxide. 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. Type of electromagnet Soft iron core (1M) Reason Soft iron core focused the magnetic flux / increase the strength of the electromagnet (1M) Terminal AB must be connected to 6V power supply (1M) -

Power supply 6V

Current flow in electric motor

Suitable connecting wire

V = IR = 160 X 10-3 X 20 (1M) = 3.2 V (1M) I = P / V = 1000 / 240 (1M) = 4.167 V (1M) Thick copper wire (1M)

Copper low resistance (1M) Thick do not melt due to high current / low resistance (1M) 10 marks

9. Characteristic W DC power supply with A is terminal positive and B is terminal negative X thermistor Y Fixed resistor Z Electromagnetic relay B Explanation npn transistor To detect the changes in temperature Together with component X act as a potential divider To switch on the second circuit (motor) 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. Characteristic Solubility in water is high Half life is 8 days Type of radiation is beta Physical state is liquid W Explanation Easy to dissolve in water Half life of 8 15 hours is a sufficient time for the worker to detect the leakage. Has medium penetration power It easy to flow in water Solubility in water is high, half life is 8 days, type of radiation is beta and the physical state is liquid. 10 marks

11

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. 2. 3. 4.

The balloon acted by two forces: Upthrust and the weight of the balloon The density of helium gas is less than the density of surrounding air Upthrust equals to the weight of the air displaced by the ballloon Upthrust is higher than the weight of the balloon

4.

1. 2. 3. 4.

Volume of air displaced equal to volume of a balloon Density of air decreased as a altitude increase Weight of displaced air become smaller 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 Bernoullis principle, the pressure in the region between both

12

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 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.

(ii)

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 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

11.

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.

13

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. 2. 3. 4.

Charges on the disc neutralize the negative charges on the ping pong ball Likes charges on the disc and the ball repelled each other The ball attracted by the positively charged disc 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. 2. 3. 4.

The two dry cells are connected in parallel The effective e.m.f. remains the same The effective internal resistance of the two cells is smaller 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. 2. 3. 4.

rotate the coil in clock wise direction the coil cut across the magnetic field current is induced in the coil 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

14

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. 2. 3. 4.

Put the radioactive source opposite the detector Detector is connected to the thickness indicator Detector detect the reading of the changes in counts If the reading of the detector is less than the specified value, the thickness of the paper is too tick / vice versa

15

SECTION 5 : PROBLEM SOLVING ( QUANTITATIVE) QUESTION 1 (a) (b) (a) (b) (a) 3 (b) (c) (a) 4 (b) (a) 5 (b) (c) 6 (a) (b) 31.25 m 5s 1600 m 2.67 ms 5 ms-2 6000 N 40 m The spring constant = gradient of the graph -1 For P , spring constant = 8 / 0.5 = 16 N cm -1 For Q , spring constant = 3 / 0.5 = 6 Ncm Elastic potential energy = x 8 x 0.5 x 10 =0.02 J 50 kg 50 kg 65 kg 2000J 3000 J v = u + 2as 2 0 = u + 2(-10)(5) -1 u = 10 m s or 72 2 2 -2 -1

ANSWER

MARK

2

3

2

2

(i)

mv = mgh 2 v = 2 gh -1 v = 10 m s 2

2

(ii) (iii) (i) (ii) 8 (iii)

9 10 11 12

(a) (b) 61200 J 84400 J (i) (ii)

E = mv 2 = ( 100/1000) (10) = 5J 2 kx = 5 J -1 k = 1000 N m 2 Px = Fx / Ax = 15 N / 0.02 m -2 = 750 Nm F = PA = (750)(0.28) = 210 N Volume of liquid transferred is unchanged A2 x2 = A1 x1 x2 = ( A1 / A2)(x1) = (0.02 / 0.28) (21) = 1.5 cm 7 1.05 x 10 J 3500 s

1 2 2 2

u = 10 cm v/u = 2 , v = 2u v = 2x10 = 20 cm v = -20 cm

2

16

QUESTION 1 f = 1+1 v u

ANSWER

MARK

1 = -1 + 1 f 20 10 f = 20 cm (i) u = 10 cm v/u = 2 , v = 2u v = 2x10 = 20 cm Convex Image formed on the screen (real) u + v = 60 cm v = 2u 1 = 1+1 f u v 1 = 1 + 1 f 20 40 f = 13 cm o 35.2 41.8o

2

2 1 1 1

13

(i)

(ii)

1 1

(a) (b) 14 (c)

(i) 15 (ii) (iii)

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 Useful energy output =0 .8 x 10 x1.5 =12 Joule Energy input = Pt = 1.2 x 5 x 4 = 24 J Efficiency = 12/24 x 100 % = 50 % I=

2

2 2 2

16

(i)

10 12

= 0.83 A (with unit) PI = (ii)

10 x100 80 12.5 / 0.052 A (accept e.c.f) 240Potential difference across P = 2 2 2

3

= 12.5 W I=

17

(i) (ii) (iii)

3500 x 6 = 2.2 V (3500 + 6000) Potential difference across Q, 6000 x 6 = 3.8 V (3500 + 6000) Ring because the voltage across Q exceed / greater than 3.2 V.

17

SECTION 6 DESIGN EXPERIMENT Q Experiment Mass of water and rise in temperature Height of magnet and induced current Mass and volume of water displaced velocity and current Manipulated Variable Mass of water Responding Variable Rise in temperature/ Final temperature Current Depth of straw sink Current induced Fixed Variable Time to heat up the water Number of coil Heat Topic

1

2

Height of magnet Mass of sand

Induced Current

3

Density of water

Hydrometer

4

velocity

Number of turns

Electromagnets

5

Volume and pressure Weight and volume of liquid displaced Current and electromagnetic strength Density of water and volume of water displaced Density of water and pressure Volume of water displaced and buoyant force Length of wire and resistance Resistance and temperature

Volume

Pressure volume of liquid displaced Number of pin attract Depth of straw sink Different depth of water level Apparent weight Resistance

Temperature Density of the liquid Number of turn of solenoid Mass of straw Depth of thistle funnel Density of water

Boyles Law Force and pressure Electromagnetic effect Buoyant Force

6

weight

7

Current Mass of salt dissolved in water Mass of salt dissolved in water Depth of rod sink in water Length of wire Temperature

8

9

Pressure in liquid

10

Buoyant Force

11

Thickness of wire Length of wire / thickness of wire Density of liquid

Electricity

12

Resistance

Electricity

13

Depth and pressure

depth

pressure

electric

18