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2005

Section A

Bahagian A

[60 marks]

[60 markah]

Answerall questions in this section.

Jawab semuasoalan dalam bahagian ini.

1.Figure below shows the scale of an ammeter.

Rajah di bawah menunjukkan skala pada sebuah ammeter.

Figure

Rajah

(a) Name the physical quantity measured by the ammeter.

Namakan kuantiti fizik yang diukur dengan ammeter.

Current/Arus

[1 mark]

[1 markah]

(b) In the space below, draw the symbol for an ammeter.

Pada ruang di bawah, lukiskan simbol bagi ammeter.

[1 mark]

[1 markah]

(c) What is the value of the smallest division on the scale?

Berapakah nilai bagi satu senggatan terkecil di skala itu?

0.1 A

[1 mark]

[1 markah]

(d) State the function of the mirror located under the scale.

Nyatakan fungsi cermin yang terdapat di bawah skala itu.

To overcome parallax error

[1 mark]

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2.Two similar louds peakers are placed 0.8 m apart. They emit a coherent sound wave. A girl walks slowly parallel

to the two loudspeakers at a distance 3.2 m in front of the loudspeakers. She hears a loud sound and weak sound

alternately. Figure below shows the positions of the loud and weak sounds.

Dua pembesar suara yang serupa diletakkan sejarak0.8 m antara satu sama lain. Pembesar suara itu

menghasilkan gelombang bunyi yang koheren. Seorang pelajar berjalan perlahan pada jarak3.2 mselari di

hadapan pembesar suara itu. Pelajar itu mendengar bunyi kuat dan bunyi perlahan berselang seli. Rajah below

menunjukkan kedudukan bunyi kuat dan bunyi perlahan itu.

Figure

Rajah

(a) What is meant by a coherent wave?

Apakah yang dimaksudkan dengan gelombang yang koheren?

Coherent waves are waves of the same frequency (same wavelength) and constant phase difference.

[1 mark]

[1 markah]

(b) The distance between three positions of the loud sound is 4.5 m, as shown in Figure above.

Calculate the wavelength of the sound wave.

Jarak di antara tiga kedudukan bunyi kuat ialah 4.5 m,seperti ditunjukkan pada Rajah di atas.

Hitungkan panjang gelombang bagi gelombang bunyi itu.

a = 0. 8 m, D = 3.2 m, x = m = 2.25 m

= 0.56

[3 marks]

[3 markah]

(c) The loud sound is heard due to the constructive interference of the sound waves. State how the constructive

interference occurs.

Bunyi kuat itu kedengaran disebabkan oleh interferens membina gelombang bunyi. Nyatakan bagaimana

interferens membina berlaku.

When the peak/trough of one wave meets with the peak/trough of another wave, constructive interference

occurs[1 mark]

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3.Figure A shows a student standing 3 m from a plane mirror in a room. The student can see the image of the wall

clock located 2 m behind him.

Rajah A menunjukkan seorang pelajar yang berdiri 3 m dari sebuah cermin satah di dalam sebuah bilik.

Pelajar itu dapat melihat imej jam dinding yang berada 2 m di belakangnya.

Figure A

Rajah A

Figure B shows the top view of the student in the room.

Rajah B menunjukkan pandangan dari atas kedudukan pelajar di dalam bilik itu.

Figure B

Rajah B

(a) Name the light phenomenon that enables the student to see the image of the wall clock in the plane mirror.

Namakan fenomena cahaya yang membolehkan pelajar itu melihat imej jam dinding di dalam cermin

satah.

Reflection of light/ Pantulan cahaya

[1 mark]

[1 markah]

(b) What is the distance between the student and the image of the wall clock?

Berapakah jarak di antara pelajar itu dengan imej jam dinding?

8 m

[1 mark]

[1 markah]

(c) The student then moves 1 m towards the plane mirror. What is the distance between the student and the

image of the wall clock?

Pelajar itu kemudian bergerak1 m ke arah cermin satah. Berapakah jarak di antara pelajar itu dengan

imej jam dinding?

7 m [1 mark]

(d) The time shown by the wall clock is 9 a.m. By drawing the hands of the clock in Figure C, complete the

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image of the wall clock in the plane mirror as seen by the student.

Jam dinding itu menunjukkan pukul9 a.m.Dengan melukiskan jarum jam pada Rajah C, lengkapkan imej

jam dinding yang diperhatikan oleh pelajar itu di dalam cermin satah.

Figure C

Rajah C

[1 mark]

[1 markah]

(e) The student moves to position X. He can see the image of the lamp in the plane mirror.

In Figure D, draw a ray diagram to show how the student can see the image of the lamp.

Pelajar itu bergerak ke kedudukan X.Dia dapat melihat imej lampu di dalam cermin satah.

Pada Rajah D, lukiskan gambar rajah sinar untuk menunjukkan bagaimana pelajar itu dapat melihat imejlampu.

Figure D

Rajah D

[2 marks]

[2 markah]

4. (a) Sweating is one of the ways our body maintains the body temperature of about 37 C. Sweat

is largely made up of water and it comes from sweat glands as shown in Figure below.

Berpeluh adalah satu cara badan kita mengekalkan suhu badan di sekitar37 C. Sebahagian

besar peluh adalah air dan ianya dikeluarkan oleh kelenjar peluh, seperti ditunjukkan pada

Rajah di bawah.

Figure

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When sweat evaporates, it takes heat away from our body.

Apabila peluh menyejat, ia mengeluarkan haba dari badan kita.

(i) What is meant by evaporation?

Apakah yang dimaksudkan dengan penyejatan?

The change of liquid into gas at the surface of the liquid happening at any temperature below the

boiling point of the liquid.

[1 mark]

(ii) Using kinetic theory of matter, explain how evaporation takes away heat from our body.

Menggunakan teori kinetik jirim, terangkan bagaimana proses penyejatan mengeluarkan haba dari

badan kita.

When a person sweats, water evaporates from the skin. Evaporation takes place when fast moving

molecules near the surface escape to the surroundings. The average kinetic energy of the molecules

left behind decreases and this causes a drop in the temperature, hence causing the cooling effect on

the body.

[2 marks]

(b) State two environmental factors that affect the rate of evaporation of sweat.

Nyatadua

faktor alam sekitar yang mempengaruhi kadar penyejatan peluh.

The flow of air/humidity of air/atmospheric pressure/the surface area of the liquid.

[2 marks]

(c) While playing badminton, 0.05 kg of sweat was evaporated from Ahmadfs body. Calculate the quantity of

heat lost from his body due to the evaporation. The latent heat of vaporisation of sweat is 2.3 10 6 J kg-1.

Semasa bermain badminton, 0.05 kgpeluh tersejat dari badan Ahmad. Hitungkan kuantiti haba yang hilang

dari badan Ahmad yang disebabkan oleh penyejatan peluh itu. Muatan haba pendam pengewapan peluh

ialah 2.3 106 J kg-1.

The heat loss/Kehilangan haba= ml

= (0.05 kg)(2.3 106J kg1)

= 1.15 105 J

[2 marks]

5. Figure A shows a piece of paper hanging from a retort stand. When air flows from the nozzle

of an air pump, the paper changes its position as shown in Figure B.

Rajah A menunjukkan sekeping kertas digantung pada satu kaki retort. Apabila udara dialirkan

dari muncung suatu pam udara, kedudukan kertas itu berubah seperti ditunjukkan pada Rajah B.

Figure A/Rajah A Figure B/Rajah B

(a) Compare the position of the paper in Figure A and Figure B.

Bandingkan kedudukan kertas itu dalam Rajah A dan Rajah B.

The position of the paper in Figure B is higher than in Figure A.

[1 mark]

[1 markah]

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(b) F is a force that causes the paper to change its position. In box X, on Figure B, indicate and label the

direction of F that acts on the paper.

F ialah daya yang menyebabkan kedudukan kertas itu berubah. Dalam petak bertanda X,pada

Rajah B, tanda dan labelkan arah Fyang bertindak ke atas kertas itu.

[1 mark]

[1 markah]

(c) Explain how F is produced.

Terangkan bagaimana F dihasilkan.

The fast flowing stream of air blown above the paper has caused the air pressure at that region to be

lower than that of the region below the paper. The difference in pressure results in a net force, F, acting

upwards.[2 marks]

[2 markah]

(d) (i) Compared to the position of the paper in Figure B, how does the position of the paper change when the

air flows faster?

Berbanding dengan kedudukan kertas itu pada Rajah B, apakah perubahan pada kedudukan kertas itu

jika udara mengalir lebih laju?

The paper will move further upwards

[1 mark]

[1 markah]

(ii) Give a reason for your answer in (d)(i).Berikan sebab bagi jawapan anda di (d)(i).

Because the difference in pressure increases and produces a greater force

[1 mark]

[1 markah]

(e) Name the principle that causes the observation in Figure B.

Namakan prinsip yang menyebabkan pemerhatian pada Rajah B.

Bernoullis principle

[1 mark]

[1 markah]

(f) Name one piece of apparatus in a school laboratory which uses the principle in (e).

Namakansatualat yang terdapat di dalam makmal sekolah yang menggunakan prinsip di (e).

Bunsen burner

[1 mark]

[1 markah]

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6. A student studies the effect of the movement of a lift on the readings of a weighing scale. The mass of the

student is 50 kg. In this study, the student stands on a weighing scale in a lift as shown in Figure below.

Seorang pelajar mengkaji kesan gerakan lif terhadap bacaan suatu penimbang. Jisim pelajar itu ialah 50 kg.

Dalam kajian ini, pelajar itu berdiri di atas penimbang di dalam lif seperti ditunjukkan pada Rajah di bawah.

Figure

Rajah

He records the readings of the weighing scale when the lift is at rest, moving up with acceleration, moving upwith uniform velocity, moving down with uniform velocity and moving down with deceleration. The readings

of the weighing scale in the study are shown in Table above.

Pelajar itu mencatatkan bacaan penimbang semasa lif itu pegun, bergerak naik dengan pecutan, bergerak naik

dengan halaju sekata, bergerak turun dengan halaju sekata dan bergerak turun dengan nyahpecutan. Bacaan

penimbang dalam kajian ini ditunjukkan dalam Jadual di atas.

Table

Jadual

(a) The mass of the student is 50 kg. What is the weight of the student in newtons?

Jisim pelajar itu ialah 50 kg.Berapakah berat pelajar itu dalam unit newton?

500 N

[1 mark]

[1 markah]

(b) State two types of movement of the lift when the reading on the weighing scale is equal to the mass of the

student.Nyatakandua jenis gerakan lif yang menunjukkan bacaan penimbang sama dengan jisim pelajar itu.

1. At rest

2. Moves up with uniform velocity/Moves down with uniform velocity

[2 marks]

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(c)Fis a resultant force that acts on the student.R is the normal reaction of the weighing scale on the student.

m is the mass of the student.gis the gravitational acceleration. Write a general equation to show the

relationship between F, R, m and g.

F ialah daya paduan yang bertindak ke atas pelajar itu. R ialah tindak balas normal penimbang itu ke atas

pelajar itu. m ialah jisim pelajar. g ialah pecutan graviti. Tulis satu persamaan umum untuk menunjukkan

hubungan antara F, R, m dan g.

R = mg + F

R = mg F

[1 mark]

[1 markah]

(d) When the lift moves up with acceleration, the normal reaction is greater than his weight. Explain why.

Semasa lif itu bergerak naik dengan pecutan, tindak balas normal lebih besar daripada berat pelajar.

Jelaskan mengapa.

The normal reaction, R, is the summation of the weight, W, and the resultant force actingupwards on

the students.

[2 marks][2 markah]

(e) (i) What is observed on the reading of the weighing scale when the lift moves down with acceleration?

Apakah yang diperhatikan pada bacaan penimbang itu semasa lif itu bergerak turun dengan pecutan?

The reading of the weighing scale decreases.

[1 mark]

[1 markah]

(ii) Give a reason for your answer in (e)(i).

Berikan sebab bagi jawapan anda di (e)(i).

Normal reaction = Weight Resultant force[1 mark]

[1 markah]

7. (a) A grazing pasture was polluted with radioactive waste from a nuclear reactor. A researcher carried out a

study on the radioactive content in the milk collected from the cows in that area. He discovered the

radioactive content in every litre of the milk was 1600 counts per minute. The researcher continued to

measure the radioactivity in the milk from that area in 10 day intervals.

Suatu kawasan padang ragut telah tercemar dengan sisa radioaktif daripada suatu reaktor nuklear.

Seorang penyelidik mengkaji kandungan radioaktif dalam susu daripada lembu yang diternak di kawasan

itu. Penyelidik itu mendapati kandungan radioaktif dalam setiap liter susu itu ialah 1600 bilangan per

minit. Penyelidik itu seterusnya mengukur keradioaktifan susu dari kawasan itu dalam sela masa setiap 10hari.

The results of the study are shown in Table below.

Keputusan kajian itu ditunjukkan dalam Jadual di bawah.

TableJadual

(i) On the graph paper below, draw a graph of radioactivity against time.

Pada kertas graf di bawah, lukis graf keradioaktifan melawan masa.

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[2 marks]

[2 markah]

(ii) Using the graph in (a)(i), determine the half-life of the radioactive material in the milk.

Show on the graph how you determined the half-life.

Dengan menggunakan graf di (a)(i), tentukan setengah hayat bahan radioaktif dalam susu itu.

Tunjukkan pada graf itu bagaimana anda menentukan nilai setengah hayat itu.

The half-life is The half-life is 7 days.

[2 marks]

[2 markah]

(iii)

Milk is safe to drink if the radioactivity in every litre of the milk is not more than 50 counts per minute.Using the half-life in (a)(ii), calculate the time when the milk from this area becomes safe to drink.

Susu selamat di minum jika keradioaktifan dalam setiap liter susu itu tidak melebihi 50

bilangan per minit. Menggunakan setengah hayat di (a)(ii), hitungkan masa susu dari kawasan itu

menjadi selamat diminum.

Time taken = 5 half-lives

The time when the milk becomes safe to drink = 5 7 days = 35 days

[2 marks]

[2 markah]

(b) In a nuclear reactor, radium-226 decays to become radon-222 by releasing one alpha particle. This reaction

experiences a mass defect.

Dalam suatu reaktor nuklear, radium-226 mereput menjadi radon-222 dengan membebaskan satu zarah

alfa. Bertindak balas itu mengalami satu kecacatan jisim.

(i) The number 226 for radium is called itsNucleon number

[1 mark]

[1 markah]

(ii) Complete the equation of the reaction by writing the appropriate number in the

boxes provided.

Lengkapkan persamaan bagi tindak balas itu dengan menulis nombor yang sesuai

dalam kotak yang disediakan.

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[1 mark]

(iii

)

The nuclear reaction of one nucleus of radium-226 experiences a mass defect of 8.6818 10 -30 kg.

Calculate the energy released in the nuclear reaction. The velocity of light is 3 10 8 m s-1.

Tindak balas nuklear bagi satu nukleus radium-226 mengalami kecacatan jisim sebanyak8.6818 10-30 kg.Hitungkan tenaga yang dibebaskan dalam tindak balas itu. Halaju cahaya adalah

3 108 m s-1.

E = mc2

E = (8.6818 1030 kg) (3 108 m s1)2

= 7.81 1013 J

[2 marks]

8. A factory producing pesticide uses a logic system to ensure the volume of pesticide in a plastic bottle is within

an acceptable range. Figure below shows the arrangement of the logic system fixed beside a conveyor belt

carrying bottles of pesticide. The radioactive detectors, S1 and S2, detect the level of radiation passing

through the bottles.Satu kilang pengeluar racun serangga menggunakan sistem logik untuk mempastikan isi padu racun

serangga yang diisi di dalam botol plastik adalah dalam julat yang diterima. Rajah di bawah menunjukkan

susunan sistem logik yang dipasang bersebelahan tali sawat yang membawa botol-botol racun serangga.

Pengesan radioaktif, S1 dan S2, mengesan tahap sinaran yang melalui

Figure

Rajah

Detectors S1 and S2 will give input 0 to the logic gate system when they receive a low level of radiation.

Detectors S1 and S2 will give input 1 to the logic gate system when they receive a high level of radiation.

Pengesan S1 dan S2 memberikan input0 kepada sistem get logik apabila menerima tahap sinaran

yang rendah.Pengesan S1 dan S2 memberikan input1 kepada sistem get logik apabila menerima tahapsinaran yang tinggi.

(a) State the level of the pesticide in the bottle if the input S1 is 0. Give a reason for your answer.

Nyatakan aras racun serangga dalam botol itu apabila inputS1 adalah 0.Berikan sebab bagi jawapan

anda.

The level of the pesticide exceeds the acceptable range. This is because only low level of radiation is

received.

[2 marks]

[2 markah]

(b) State the level of pesticide in the bottle if the input S2 is 1. Give a reason for your answer.

Nyatakan aras racun serangga dalam botol itu apabila S2adalah 1.Berikan sebab bagi jawapan anda.

The level of the pesticide does not fulfil the acceptable range. This is because high-level radiation is

received.

[2 marks]

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Figure below shows two combinations of logic gates, P and Q, that are suggested to develop Use

the logic gate system.

Rajah di bawah menunjukkan dua kombinasi get logik, P dan Q,yang dicadangkan untuk membina

sistem get logik ini.

Figure

Rajah

(c) Name the logic gate M.

Namakan get logikM.

OR gate

[1 mark]

[1 markah]

(d) Complete the truth tables for P and Q.

Lengkapkan jadual kebenaran bagi P dan Q.

For P/Q

The table truth table of P The truth table of Q

Jadual kebenaran bagi P Jadual kebenaran bagi Q

[4 marks]

[4 markah]

(e) When the output of the logic gate system is 1, it indicates the volume of the pesticide in the bottle

is within the acceptable range. When the output of the logic system is 0, it indicates the volume of the

pesticide in the bottle is outside the acceptable range.

Apabila output sistem get logik ini adalah1, ia menandakan isi padu racun serangga di dalam botol

adalah di dalam julat yang diterima. Apabila output sistem get logik ini adalah 0, ia menandakan isi padu

racun serangga di dalam botol adalahdi luar

julat yang diterima.(i) Based on the output of the truth tables in (d), which combination of logic gates is suitable to be used for

the logic gate system?

Berdasarkan output dalam jadual kebenaran di (d), kombinasi get logik yang manakah sesuai

digunakan untuk get logik ini?

Combination of logic gates: Combination of logic gates P.

[1 mark]

[1 markah]

(ii) Give two reasons for your choice.

Berikan duasebab bagi pilihan anda.

1. When input S1 is 1 and input S2 is 0, combination P gives an acceptable output.

2. When both inputs are 0 or 1, the output is not acceptable.

[2 marks]

[2 markah]

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Section B

Bahagian B

[20 marks]

[20 markah]

Answer any one question from this section.

Jawab mana-mana satusoalan daripada bahagian ini.

9. (a) A fisherman finds that his boat is at different levels in the sea and in the river, although the boat carries

the same load. The density of sea water is 1 025 kg m -3 and of river water is 1 000 kg m-3.

Figures A and B illustrate the situation of the boat in the sea and in the river.

Seorang nelayan mendapati botnya pada aras yang berbeza semasa di laut dan di sungai, walaupun bot

itu membawa muatan yang sama. Ketumpatan air laut ialah 1 025 kg m-3dan ketumpatan air sungai

ialah 1 000 kg m-3.Rajah A dan B menggambarkan situasi bot itu ketika di laut dan di sungai.

Figure A Figure B

Rajah A Rajah B

(i) What is meant by density?

Apakah yang dimaksudkan dengan ketumpatan?

Density is defined as the mass per unit volume of a substance.[1 markah]

(ii) Using Figures A and B, compare the levels of the boat and the volumes of water displaced by the boat.

Relating the mass of the boat with its load, the volume of water displaced and the density of the water,

deduce a relevant physics concept.

Menggunakan Rajah A dan B, bandingkan aras bot dan isi padu air yang disesarkan oleh bot itu.

Hubungkaitkan antara jisim bot bersama muatannya, isi padu air yang disesarkan dan ketumpatan

itu, untuk menyimpulkan satu konsep fizik yang sesuai.

The boat submerges more in the river than in the sea.

The volume of river water displaced is more than the volume of sea water displaced. The mass of river water displaced is the same as the mass of sea water displaced.

The buoyant force acting on the boat in Figure A is the same as that acting on the boat in Figure B.

As the density of the water increases, the volume of water displaced decreases and vice-versa.

[5 marks]

(iii

)

Name the physics principle that explains the above situation.

Namakan prinsip fi zik yang menerangkan situasi di atas.

Archimedes principle

[1 markah]

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(b) A submarine can sail on the sea surface and under the sea. Explain how a submarine on the surface

submerges.

Suatu kapal selam boleh belayar di permukaan laut dan di dalam laut. Terangkan bagaimana suatu kapal

selam yang berada di permukaan laut tenggelam ke dalam laut.

When a submarine is floating partially above water, its ballast tanks are only partially filled with

water and the weight of the submarine is equal to the buoyant force.

When the ballast tanks are filled with sea water, the weight of the submarine increases..

This causes the submarine to sink into the sea water as its weight is greater than the buoyant force.

[3 marks]

(c) Figures C and D illustrate the working principle of a hydrometer. The depth to which the test tube sinks

depends on its surrounding liquid.

Rajah C dan D menggambarkan prinisp kerja hidrometer. Kedalaman tabung uji itu tenggelam

bergantung kepada ketumpatan cecair di sekitarnya.

Figure C/Rajah C Figure D/Rajah D

Explain how you would design a hydrometer that can determine a wide range of densities of liquid,

using the idea of the working principle of a hydrometer shown above. Draw a diagram that shows the

design of your hydrometer and in your explanation, emphasise the

following aspects:Terangkan bagaimana anda merekabentuk satu hidrometer yang boleh menentukan ketumpatan cecair

dalam julat besar, dengan menggunakan idea tentang prinsip hidrometer yang ditunjukkan di atas.

Lukiskan gambar rajah yang menunjukkan reka bentuk hidrometer anda dan dalam penerangan dan anda

diberikan penekanan bagi aspek-aspek berikut:

(i) the stability of the hydrometer,

kestabilan hidrometer itu,

The lead shots at the base lowers the centre of gravity of the hydrometer

Cylinder with a bigger diameter at the lower section

To enable the hydrometer to float upright in a liquid and not overturn

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(ii) the sensitivity of the hydrometer,

kepekatan hidrometer itu,

The cylinder must have a small diameter on the upper section

A small reading scale can be incorporated

(iii

)

the ability to measure a wide range of densities of liquids,

kebolehan menentukan ketumpatan cecair dalam julat yang besar,

The cylinder must be long

The scale can be made bigger and cover a wide range of densities

(iv)the calibration of the hydrometer.

penentukuran hidrometer itu.

The hydrometer is floated in a liquid with a known density like water. The liquid level at

the stem is marked.

For every liquid with a known density, the level of the liquid on the hydrometer stem is marked. The difference in the liquid levels can be used to calibrate the stem of the hydrometer.

[10 marks]

[10 markah]

10. Figure A shows the arrangement of the apparatus for an experiment to study a wave phenomenon.

Rajah A menunjukkan susunan radas bagi eksperimen untuk mengkaji satu fenomena gelombang.

Figure A

Rajah A

Figure B shows the bright and dark bands of the wave pattern formed on the screen when plane waves pass

trough narrow and wipe gaps.Rajah B menunjukkan jalur terang dan jalur gelap bagi corak gelombang yang terbentuk pada tabir apabila

gelombang satah melalui celah kecil dan celah besar.

Figure B

Rajah B

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(a) (i) Explain how the dark and light bands are formed on the screen.

Terangkan bagaimana jalur terang dan jalur gelap terbentuk pada tabir.

The water waves formed are like convex and concave lenses

This causes the parallel light rays from the lamp to converge forming bright spots and diverge

Forming dark regions.

[4 marks]

(ii) Observe Figure B. Compare the wave patterns and the wavelengths of the waves before and

after they pass through the gaps.Relate the size of the gaps, the wave patterns and the wavelengths to

deduce a relevant physics concept.

Perhatikan Rajah B. Bandingkan corak gelombang dan panjang gelombang sebelum dan selepas

gelombang air itu melalui celah-celah itu. Hubungkaitkan antara saiz celah, corak gelombang dan

panjang gelombang untuk menyimpulkan suatu konsep fizik yang sesuai

The wavelengths of the waves before and after passing through the narrow and wide gaps are the

same

Before passing through the narrow and wide gaps, plane wavefronts can be observed.

After passing through the gaps, the waves emerging from the gap have circular wavefronts

The curvature of the bending is more obvious in the diagram, where the gap is narrower.

When a wave passes through a gap, the wave bends. The narrower the size of the gap is, the

bigger the bending/ curvature of the wave will be.

(iii

)

Name the wave phenomenon shown in Figure B.

Namakan fenomena gelombang yang ditunjukkan pada Rajah B.

Diffraction of waves

[1 mark]

(b) Figure C shows the seashore of a fishing village. During the rainy season , waves are big. One year

the waves eroded the seashore, caused the jetty to collapse and damage the fishermenfs boats.

Rajah C menunjukkan pantai bagi satu kampung nelayan. Semasa musim tengkujuh, saiz gelombang

adalah besar. Pada suatu tahun gelombang ini menghakis pantai meruntuhkan jeti dan merosakkan bot-

bot nelayan.

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Figure C

Rajah C

To prevent similar damage in the future, the fishermen suggest building retaining walls and relocating

the jetty. Make further suggestions of ways to help the fishermen solve their problems. You should use

your knowledge of reflection, refraction and diffraction of waves to explain these suggestions, to include

the following aspects:

Untuk mengelakkan kerosakan yang serupa berulang pada masa hadapan, nelayan-nelayan itu bercadang

untuk membina benteng dan memindahkan jeti ke tempat yang baru. Buat cadangan selanjutnya tentang

cara untuk membantu nelayan itu mengatasi masalah mereka. Anda perlu menggunakan pengetahuantentang pantulan, pembiasan dan pembelauan gelombang bagi menerangkan cadangan itu, yang

merangkumi aspek-aspek berikut:

(i) the design and structure of the retaining wall,

reka bentuk dan struktur benteng,

Concrete structures, solid and rigid

Can withstand the impact of the waves, not easy to crack

Has narrow gaps

Diffraction will occur, the smaller amplitude of the diffracted waves causes the sea to be calm

Must be high To ensure no overspill of the waves

(ii) the location of the new jetty,

lokasi jeti yang hendak dibina,

The new jetty is built in the region of the bay

The waves in the bay are calmer (amplitude is lower) than in the cape

(iii

)

the size or energy of the waves.

saiz atau tenaga gelombang.

The wave energy diverges at the bay

The wave energy converges at the cape

The amplitude and size of the waves are smaller at the bay

[10 marks]

[10 markah]

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Section C

Bahagian C

[20 marks]

[20 markah]

Answer any one question from this section.

Jawab mana-mana satusoalan daripada bahagian ini.

11. (a) Figure A shows two convex lenses, R and S, used in an astronomical telescope.

The focal length for R is 40 cm and for S is 10 cm .

Rajah A menunjukkan dua kanta penumpu, Rdan S,yang digunakan dalam teleskop astronomi.

Panjang fokus bagi Rialah 40 cm dan panjang fokus bagi S ialah 10 cm.

Figure A

Rajah A

(i) Define the power of a lens.

Definisikan kuasa kanta.

Power of the lens =

[1 markah]

(ii) Give two reasons why R is used as the objective lens of the telescope.

Nyatakan duasebab mengapa Rsesuai digunakan sebagai kanta objek dalam teleskop.

Has a larger surface area which allows more light in

Has a longer focal length [2 markah]

(iii

)

Using lenses R and S, draw a ray diagram on Figure A to show the formation of the final

image by the telescope at normal adjustment. Use a scale of 10 cm to 1 cm.

Menggunakan kanta Rdan kanta S, lukiskan Rajah A, satu gambar rajah sinar

untukmenunjukkanpembentukan imej akhir oleh teleskop itu pada pelarasan normal. Gunakan

skala 10 cm kepada 1 cm.

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[5 markah]

(iv)Calculate the magnification of the final image formed by the telescope at normal adjustment.

Hitungkan pembesaran imej akhir yang dibentuk oleh teleskop pada pelarasan normal.

Magnification = Focal length of objective lens/Focal length of eyepiece

[2 markah]

(b) Presbyopia is an inability of the eye to adjust the focussing of far and near objects. This usually happens

when we get old, where the ciliary muscle is less able to change the shape of the eye lens to focus the

image on the retina, as shown in Figures B and C.

Presbiopia ialah keadaan di mana mata tidak boleh memfokus objek jauh dan objek dekat. Keadaan ini

biasanya berlaku apabila kita telah tua, disebabkan otot silia pada mata kurang kenyal untuk mengubah

bentuk kanta semasa memfokus ke retina, seperti ditunjukkan pada Rajah B dan Rajah C.

Figure B Figure C

Rajah B Rajah C

As an optician, you have three designs of lenses, X, Y and Z, in your shop. The cross-section of X,

Y and Z are shown in Figure D.

Sebagai seorang pakar optik, anda mempunyai tiga reka bentuk kanta, X, Y dan Z, di kedai anda. Keratan

rentas X, Y dan Z ditunjukkan pada Rajah D.

Figure D

Rajah D

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(i) Choose the most suitable design of lens in Figure D to correct the sight of a person with

presbyopia and explain the suitability of the design.

Pilih reka bentuk kanta pada Rajah Dyang paling sesuai untuk membetulkan penglihatan seorang

yang mengalami presbiopia dan terangkan kesesuaian reka bentuk kanta itu.

Most suitable for making a lens: Design Y

Contains both diverging and converging lenses

A diverging lens can be used to focus the image from a distant object onto the retina

A converging lens can be used to focus the image from a near object onto the retina

(ii) Explain why the other two designs are not suitable. Either low or high refractive index glass can be

used to make the lenses.

Terangkan mengapa dua reka bentuk kanta yang lain tidak sesuai. Kaca mempunyai indeks biasan

yang rendah atau yang tinggi boleh digunakan untuk membuat kanta.

Design X does not allow the image of a distant object to be focused onto the retina, so the distant

object cannot be seen clearly.

Design Z does not allow the image of a near object to be focused onto the retina, so nearobject cannot be seen clearly.

(iii

)

Which type of glass is most suitable to make the lens chosen in (b)(i)? Give reasons for your choice.

Jenis kaca yang manakah sesuai untuk membina kanta yang anda pilih di (b)(i)?Berikan sebab bagi

pilihan anda.

Glass with a high refractive index is suitable to be used to make the lens. This produces a lighter

and thinner lens

[10 marks]

[10 markah]

12. (a) Most of our electrical energy comes from hydroelectric power stations and thermal power

stations. These power stations are connected by cables to transmit electricity to users in industries,

offices, schools and houses. This system is called the national grid network.

Sebahagian besar tenaga elektrik yang digunakan datang daripada stesen janakuasa elektrik

hidro dan stesen janakuasa termal. Stesen janakuasa ini disambung antara satu sama lain

menggunakan kabel untuk menyalurkan tenaga elektrik kepada industri, pejabat, sekolah dan

rumah kediaman. Sistem ini dikenali sebagai rangkaian grid nasional.

(i) State the transformations of energy in a hydroelectric power system.

Nyatakan pemindahan bentuk tenaga yang berlaku di stesen janakuasa elektrik hidro.

Potential energy Kinetic energy Electrical energy[1 markah]

(ii) Explain briefly the importance of the national grid network system in distributing electrical

energy to the user

Terangkan secara ringkas kepentingan sistem rangkaian grid nasional dalam penghantaran

tenagaelektrik kepada pengguna.

The cost of generation of electricity is reduced because high voltage transmission of

energygreatly reduces energy loss in the cables.

Repair work and maintenance can be carried out at any power station at any time

To ensure the supply of the power is continuous

The generation of electricity by each station can be controlled and regulated according tothe demand pattern

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(b) Figure below shows how a model of an electric transmission system can be set up in a laboratory.

The model consists of a power station that generates 12 V of alternating current (a.c) that

transmits the electrical energy to the users using transmission wires and transformers P, Q and R.

Rajah di bawah menunjukkan satu model sistem penghantaran tenaga elektrik yang boleh dibina

di dalam makmal. Model ini mengandungi satu stesen janakuasa yang menjana 12 V arus ulang

alik(a.u) yangmenghantar tenaga elektrik kepada pengguna menggunakan dawai penghantar

dan transformerP, Q dan R.

Figure

Rajah

You are required to set up a model as in Figure above using the information in Table below.

Anda dikehendaki untuk menyediakan model seperti dalam Rajah di atas dengan menggunakan

maklumat dalam Jadual di bawah.

Table

Jadual

Using the information in Figure and Table above determine:Menggunakan maklumat dalam Rajah dan Jadual di atas tentukan:

(i) the number of turns in the primary coil and the secondary coil of transformers P, Q and R and

show your working.

bilangan lilitan dalam gegelung primer dan bilangan lilitan dalam gegelung sekunder

transformerP, Q, danR, tunjukkan kerja hitungan yang anda lakukan.

For transformer P(12 V 24 V):

Choose Np = 500, Ns = 1 000

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For transformer Q (24 V 8 V):

Choose Np = 1 200, Ns = 400

For transformer R (24 V 6 V):

Choose Np = 500, Ns = 120

(ii) the type of core you will use in all transformers and justify your choice.

jenis teras yang anda gunakan bagi semua transformer itu dan jelaskan pilihan anda.

- Laminated soft -iron core Soft iron can be easily magnetized and demagnetized. Therefore, reducing hysteresis loss

A laminated core is used for reducing the eddy current/induced current in the core, hence

reducing the power loss of the transformer.

(iii

)

the material you will use for the transmission wire and justify your choice.

bahan yang anda gunakan untuk membina dawai penghantar dan jelaskan pilihan anda.

Aluminium

Aluminium has a low resistance per metre, and so the power loss from the transmission

wire will be reduced.

Copper wire has a lower resistance per metre than aluminium but it is expensive and ithas a much higher density than aluminium

[10 marks]

(c) If the resistance of the transmission wires between transformers P and Q in the model at Figure

above is 30 , calculate:

Jika rintangan dawai penghantar antara transformerP dan transformerQ dalam model pada

Rajahdi atas ialah 30 , hitungkan:

(i) the current that flows in the transmission wire,

arus yang mengalir dalam dawai penghantar itu,

V = 24 V,R = 30

Current =

= 0.8 A

(ii) the power loss due to the heating effect of the current in the transmission wire.

kuasa yang hilang disebabkan oleh kesan pemanasan arus dalam wayar penghantar itu.

Power loss in the cables = I2R

= (0.8)2(30 )

= 19.2 W

[5 marks]