# marking scheme perfect score physics module 2008

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SEKOLAH

SEKTOR SEKOLAH BERASRAMA PENUH BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH DAN KLUSTER KEMENTERIAN PELAJARAN MALAYSIA

MARKING SCHEMEPERFECT SCORE MODULE

PHYSICS

2008

SBP 2008

1

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MODEL ANSWER PHYSICS PERFECT SCORE 2008SECTION 1 - CONCEPTUAL QUESTION (a) (b) (c) (d) (a) (b) i ii iii (c) i ii (d) (e) (a) i ii (b) i ii iii (a) (b) 4 (c) (d) (e) (a) (b) i ii iii Iv (c) i ii (a) (b) (c) (d) (e) (f) ANSWER Weight/ air resistance Bigger Different: Velocity (terminal) water droplet > velocity (terminal) feather Velocity (terminal) increase when the decrease of surface area / Velocity (terminal) inversely proportional with the surface area. Density is the mass per volume Level of the boat is higher in the sea than in the river. Water displaced in the sea is less than in the river. Density of sea water is higher than river water. The lower the density of water, the greater /higher the volume of water displaced. Weight of the boat = Weight of the water displaced Archimedes principle // Bouyancys law Ballast tank filled by sea water Weight of submarine > upthrust The temperature of air increase The volume of air increase The mass of air constant When the temperature increase the volume of air increase Charles Law Temperature increase, the kinetic energy increase The rate of collision increase/ pressure increase and expand the ballon/ball Length between the two crest / trough / consicutive wave front The water wavelength remains constant after went through the gap. The wavelength in 4.2 is greater than 4.1 Curvature of the wave pattern in fig. 4.2 is more greater / Diffraction of waves is more in 4.2 The greater the wavelength, the wave pattern more spread or curve after went through gap. Diffraction same M1 brighter than M1 V 1 is bigger than V2 V 3 = V 1 +V 2 A1 = A2 + A3 Series circuit Not suitable If one bulb blown up ( does not light up) all the bulb will not funtion 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 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 1 1 1 1 1 1 1 1 1 2 1 1 1 1

1

2

3

5

6

SBP 2008

2

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QUESTION i

7

ii

ANSWER Buoyant force is an upward force acting on an object immersed in a fluid The mass of the catch does not change through out the whole act of lifting the net The volume of the catch still in the water is getting smaller/is the least in Figure 9.3 and the largest in Figure 9.1 The force needed to lift the catch is getting bigger. / in Figure 9.3 is the greatest The weight of water displaced is getting smaller / the greatest in Figure 9.1 and the least in 9.3 Buoyant force is equal to weight of water displaced The greater the weight of water displaced the greater the buoyant force

MARK 1 1 1 1 1 1 1 (Any 5) 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 1 1 1

i 8

Ii

(a) 9 (b) (c) (a)

10

(b)

(a)

11

(b)

12

(a)

13 (b)

Distance from the optical centre to a focal point. Lens K is thicker than lens J Light ray is refracted more in lens K than lens J. Focal length of lens K is shorter than lens J. Therefore the thicker the lens, the greater the refraction of light and with that the shorter the focal length of a lens will be magnetic field region The number of turns of the coil in diagram 3.2 is more // vice versa The arrangement pattern of the iron filings in diagram 3.1 is further apart. The angle of deflection of diagram 3.2 is more. The closer the pattern of iron filing the greater the strength of magnetic field. The strength of magnetic field increases as the number of turns increases// vice versa. Electric current is the rate of flow of charge. 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 charge flows Diagram 11.1 connected in series and Diagram 11.2 connected in parallel The reading of ammeter in Diagram 11.2 is greater than in Diagram 11.1. The reading of voltmeter in Diagram 11.1 > Diagram 11.2. The effective resistance in Diagram 11.2 < Diagram 11.1. Effective resistance increases, the current flows decreases. Circuit connected in parallel, the effective resistance decreases The light bulb in diagram 12.2 does not light up while the light bulb in diagram 12.1 light up In diagram 12.2 the negative terminal cell is connected to the anode. This increase the junction resistance in diagram 12.2 The current cannot flow through the junction. The diode in diagram 12.2 is reversed bias. Concept Diode allows current to flow in one direction. Nuclear fission is the splitting of a heavy nucleus into two lighter nuclei, which subsequently emit either two or three neutrons and release of large amounts of energy. // the high number mass/ high nucleon number to small nucleus Difference: State that nuclear fission involves the fission of heavy nucleus. State that nuclear fusion involves the combination of lighter nuclei Similarities: State that decrease/loss of mass after the process occurs. State that the neutrons are produced. State that nucleon number/ mass number/ atomic number before and after are the same 2 E = mc // loss of mass/ mass defect directly proportional to the energy released .

1

1 1 1

1

SBP 2008

3

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SECTION 2 PROBLEM SOLVING (QUALITATIVE) QUESTION 1 Elastic potential energy (i) [1 mark] (iii)

1

(ii) a (iii)

k=

F , x

k=

3.6 4

1-1

k = 0.9 N cm E = Fx

2 = x 3.6 x 4/100 = 0.072 J

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

x=

5 0.9

2

l = 12 5.56 = 6.44 cm The compression of the spring is directly proportional to the load Exceed the elastic limit of the spring/ Spring does not return to its original condition after the applied force has been removed. Connect the spring in parallel Use spring with larger spring constant. Use spring with smaller diameter. TOTAL

1 1 2

10

QUESTION 2 (i) Pascal Principle a (ii) Oil cannot be compressed (i) 5 000 Nm F = PA b (ii) = 10 000N m = 1 000 kg (iii) move downward Increase diameter of the piston c Use thicker wall cylinder d Hydraulic brake TOTAL

1 1 1 1 1 1 1 1 1 1 10

QUESTION 3 a n-p-n transistor (i) 12 V (ii) 27 + 3 = 30 k b (iii) V YZ =

3 x 3 + 27

1 1 1 1 12 1 1 1 1 1 1 10

c d e

= 1.2 V 1- Lamp L will not glow 2- because the voltage across YZ (i.e 1.2 V) is less than the base-emitter potential difference of 2V Resistor R1 and R2 are swapped places 1-Resistor R1 is replaced by a thermistor. 2- Lamp L is replaced by an electric bell. TOTAL

QUESTION 4 (i) 0111 (ii) 1000 a (iii) 0001 (iv) 1110 b (i) 0001

1 1 1 1 1

SBP 2008

4

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(ii) c

AND

1

Q

Q

1

Qd

P RTOTAL

3

10

QUESTION 5 Suggestion 1 2 3 4 5 6 7 8 9 Balloon should be large size Balloon material is made of light weight material like nylon Balloon material should also have a high melting point. The part of the balloon (the skirt) near the burner must be fire resistant /coated with fire resistant material The burner burns (liquefied) propane/gas A large fan is needed initially The basket must be made off light and flexible/safe material (e.g. rattan or cane woven) There must be a line or rope from the balloon to the ground Best times to launch the balloon are early morning and late afternoon when the air is cooler Rationale To create sufficient buoyant force due to greater weight of surrounding air displaced. The total weight of the balloon is less than the buoyant force//reduce weight It will not disintegrate when exposed to hot air So that it doesnt catch fire easily Warms up the air in the balloon To blow enough air into the balloon Prolong the collision time between basket and ground// reduce impulsive force when basket hits the ground Prevents the balloon from being swept away from the carnival site. Cool air is denser, providing more buoyant force TOTAL QUESTION 6 Suggestion Rationale Choose lens S as objective lens Choose lens Q as eyepiece Lens S is placed in front of lens Q The two lenses are adjusted so that they are in normal adjustment where distance between the two lenses is equal to (fo + fe) Modification Explanation Use low power convex lens as the objective lens. (ii) Use high power convex lens as the eye lens Use bigger diameter of objective lens Magnification of telescope = 1 1 1 1 10 MARK

Any 5 correct

(i)

fo fe

,

1 1 1 1 1

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