# scheme physics perfect score 2012     Post on 18-Apr-2015

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Semoga bermanfaat kepada semua.. calon SPM 2013

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BAHAGIAN PENGURUSAN

SEKOLAH BERASRAMA PENUH SEKOLAH KECEMERLANGAN

KEMENTERIAN PELAJARAN MALAYSIA

MARKING SCHEMEPERFECT SCORE & X A-PLUS MODULE

PHYSICS

2012

SECTION II - COMMON MISTAKES AND MISCONCEPTIONS8. Physical Quantity Stop watch voltmeter thermometer Bourdon gauge Ammeter 9. Terms [The type of energy when the object is at P] a Gravitational Potential Energy Potential energy Common Mistake Correct Answer Physical quantity measured time Voltage, V temperature Gas pressure Electric current Physics Unit and symbol Second. s Volt, V Kelvin or oCelsius Pascal, Pa Ampere, A

Force acting on surface area b Pressure Force/area A product of depth, density and gravitational acceleration c Pascals principle In a close container, force is In a close container, pressure is transmitted equally transmitted equally. Heat absorbed to change by 1oC Heat absorbed to change 1 kg of liquid to gas without any changes in temperature. Normal force acting on a unit of surface area

d

Latent heat of vaporization

e

Temperature

Transfer from hot body to cold body

Amount of kinetic energy in an object

[Physics phenomena in a prism] Total internal reflection

f

Reflection

Terms

Common Mistake Critical angle is when the refracted angle is 90o Critical angle is the incident angle when the reflected angle is 90o The image that formed behind the lens

Correct Answer Critical angle is the incident angle in denser medium which produces when the refracted angle in less dense medium is 90o The image that cannot formed on the screen be

g

Critical angle

h

Virtual image

i

Monochromatic light

A colour of one light

light of one frequency / wavelength / colour .. displacement of any particle/oscillating system from its .. ..

j

Amplitude

Maximum point of the highest displacement

k

Period

One complete oscillation

The time taken for any particle to make one complete oscillation

l

Specification: 240 V, 1000 W

1000 W of energy is supplied when the power supplied is 240 V.

1000 W of energy is consumed in 1 s when connected to a 240 V power supply.

j

electromagnet

When the current flow through magnet Is a combination of electric and magnetic field Negative charge

A conductor which can produce magnetic field when current passes through it.

k

Beta particles

Fast moving electron

B.

Misconceptians Examples: Num

Misconceptions

Correction

1

Oil is used in hydraulic jack because it has higher boiling point Snells law state that:

.. because it is not easily evaporate.

2

The sine of incident angle The sine of refracted angle

=

Refractive index

The sine of incident angle The sine of refracted angle

=

constant

Container A

Container B

water 3 The force exerted at X > the force exerted at Y because smaller surface area (P = F /A)

Pressure at X = Pressure at Y because X and Y are at the same depth, same gravitational acceleration and in the same type of liquid that has same density. ( P = hg)

To increase the efficiency of ac/dc GENERATOR: Use more number of turns to produce stronger magnetic field

Generator the current is induced

The ship can float in sea water because the total density of the ship is less than the density of water The buoyant force is equals to the total weight of the ship

The ship can float in sea water because the buoyant force is bigger than the weight of the ship

C. Paper 3

1.

Data Tabulation Title ContentExample: Common Mistake Correct Answer no unit not consistent

Electric Current 0.1 0.12 0.14

Voltage 0.5 1 1.5

Electric Current, I (A) 0.10 0.12 0.14

Voltage, V (V) 0.5 1.0 1.5

TOV 1 SPM FORMAT SET 14531/2 SECTION A Question 5 No a b(i) b(ii) b(iii) c d(i) d(ii) d(iii) Answer Scheme The force that gravitation exerts upon a body The mass of slotted weigh in Diagram 5.1 > Diagram 5.2 The nett force in Diagram 5.2 > Diagram 5.1 The acceleration in Diagram 5.2 > Diagram 5.1 The greater the nett force , the greater the acceleration Net force in Diagram 5.1 > Diagram 5.3 The acceleration in Diagram 5.1 > Diagram 5.3 The weight of 20 N in Diagram 5.1 is perpendicular to the tension of the string Mark 1 1 1 1 1 1 1 1

Question 6 No a(i) a(ii) b(i) b(ii) c d Answer Scheme Diagram 6.1 : no relative motion Diagram 6.2 : there is a relative motion Number of turns in Diagram 6.3 > Diagram 6.2 The greater the number of turn of coil, the greater the change in magnetic flux The greater the number of turn of coil, the greater the magnitude of induced current Faradays Law When the magnet is pulled away from the coil Reason : the current will flow in such direction that oppose the change that cause it Mark 2 1 1 1 1 2

Question 7 No a b c d(i) d(ii) d(iii) Answer Scheme Depth of water P = hg5 = 2.5 x 103 x 10 = 2.5 x 104 N m-2 Less different of water pressure Place the water tank P higher than water tank R // use water pump It will increase the water pressure // sufficient water supply Bigger base area //thicker wall at the bottom Less pressure exerted on the ground // could withstand water pressure Low density material // fiber tank Light // can withstand stronger pressure Mark 1 2 1 2 2 2

Question 8 No 1. (a) Answer Scheme Atmospheric pressure is the weight of the atmosphere on an object 1. (b) 2. 3. Vacuum pump is used to pump out the air from the suction cup Partial vacuum is created in the suction cup Higher atmospheric pressure push the glass sheet onto the suction cup Mark 1 3 1 1 1 1 1 1 1 1

Low pressure Larger difference in pressure (c)(i) Big diameter cup Greater force (ii) Triple cups Greater force (iii) R Straw/syringe/siphon/vacuum cleaner (iv) (d)

12

Question 9 No a Answer Scheme The force exerted by the gas molecules onto a unit of surface area Mark 1

No b

c

Answer Scheme When temperature increases, the average kinetic energy increases Rate of collision also increase Rate of change of momentum increase Force exerted on a unit of surface area increase Temperature of gas : 9.3 > 9.2 Volume of gas : 9.3 = 9.2 Reading of pressure gauge : 9.2 < 9.3 Temperature increase, reading of pressure gauge Pressure Law Characteristics Large radius Many tyres Explaination Rate of rotation is less // Temperature does not increase easily Increase the surface area // less pressure Provide a gripping surface Prevent from deformation Can withstand high temperature

Mark 4

5

d

Tyres with treads Strong tyre High melting point

10

Question 10 No a b Number of turns of coil : Diagram 10.3 > Diagram 10.4 Speed of magnet : same c Deflection of galvanometer : Diagram 10.3 > 10.4 When number of turns of coil increased, deflection also increased Faradays Law Characteristics Curve magnet Stronger magnet d Replace component X with commutator Copper wire coil Thick copper wire Explaination Produce radial magnetic field Produce stronger magnetic field Current is induced in one direction Good conductor Less resistance 10 5 Answer Scheme Electromagnetic induction Mark 1 4

Question 11 (a) (b)(i) Distance between optical centre and focal point M1 correct substitution into formula or correct answer M = v/u = 60/20 = 3 (b)(ii) M1 correct substitution into formula:

M2

Answer with correct unit f = 15 cm = 0.15 m

(b)(iii)

M1: M2:

P = 100/f = 100/15 Answer with correct unit: = 6.67 D Parallel light rays from the hot sun at infinity pass through a convex lens// labeled diagram Light rays are focused after passing through the lens // labeled diagram Light rays are converged onto a focal point of the lens At the point, the intensity of lights is great (and the light energy) causes an increases in temperature. When the spot on the paper become hot enough, the paper start to burn // light energy change to heat energy. Aspect Reason Focal length is longer // eyepiece must be more longer focal length than objective lens Focal length is shorter / objective lens must be powerful lens than eyepiece lens// Objective lens must be shorter focal length than eyepiece lens. To produce bigger image from the eyepiece // to increase the magnification To produce real, inverted and magnified image Focal length of eyepiece is longer than objective lens, distance between lenses is greater than (fo + fe), and the position of the specimen is between fo and 2 fo

(c)

M1:

M2: M3: M4:

Low power of eye piece High power objective lens Distance between lenses : >fo + fe Position of the specimen : fo< u < 2fo The most suitable is : microscope M

Question 12 Answer: (a) frequency (b) 1 High pitch, high frequency / pitch directly propotional to frequency 2 frequency is inversly propotional to wave length // high frequency has shorter wave length 3 Short / high f / high pith at C, will diffract / spread out/ bend less 4 Sound easily diffracted / bending / spread out during low pitch/ low f/long / at (c) Reason Receive more signal Signal are focused/converged to the receiver Has high frequency / high energy The signal is not blocked / easy to be High detected Choose K because Because it has large diameter, Same as focal length, use microwave and locate at high position. Characteristic Large diameter Same as focal length Microwave A,B,C

(d)(i) v = 2s/t = (2 x 90)/0.12 = 1 500 m/s (i) V = f = 1 500/50 000 = 0.03 m = 3 cm TOV 2 SPM FORMAT SET 2

4531/2 SECTION A

QUESTION 5

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