physics perfect score module (answer)

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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







(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


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




1 1


(b) (c) (a)

2 1 1 1 1 1



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




(a) 14 (b)


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


(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


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


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 arr