physics HOTS KBAT questions

CHAPTER 4 : HEAT

4.1 Understanding Thermal Equilibrium Aras : Aplikasi The hand feels cold after it is rubbed with ethanol because Tangan akan berasa sejuk selepas disapu dengan ethanol kerana A the temperature of the ethanol is lower than the body temperature Suhu etanol lebih rendah dari suhu badan B ethanol on the skin prevents the loss of heat from the body etanol yang disapu di atas kulit menghalang tenaga haba bebas dari badan C Heat is transferred from ethanol to the body Haba dipindahkan dari etanol ke badan D when ethanol evaporates, heat is absorbed from the body apabila etanol tersejat, haba di pindahkan ke badan Ans : D

4.1 Understanding Thermal Equilibrium Aras : Analisis Diagram 2 shows two beakers, P and Q. Rajah 2 menunjukkan dua buah bikar, P dan Q.

Beaker P

Beaker Q

Bikar P

Bikar Q

200 g of water at 90˚C

100 g of water at 30˚C

200 g of water at 90˚C

100 g of water at 30˚C

Diagram 2 /Rajah 2

The water in beakers P and Q are mixed.

Which graphs shows the correct temperature

change, θ, with time, t, until thermal equilibrium is achieved? Air dalam bikar P dan Q dicampurkan. Graf manakah yang menunjukkan perubahan suhu, θ, dengan masa, t, sehingga keseimbangan terma tercapai? A

C

θ /°C

θ /°C

90

90

30

30

t /min

t /min

B

D

θ /°C

θ /°C

90

90

30

30

t /min

t /min

Answer : A

4.1 Understanding Thermal Equilibrium Aras : Analisis Name the physical quantity that determines the direction of heat flow? A Heat B Temperature C Specific heat capacity D Mass Ans : B

4.2 Understanding Specific Heat Capacity Aras : Menilai More heat energy is required to change 1 kg of water at 100C to steam than melting 1 kg of ice because Lebih banyak haba diperlukan untuk menukarkan 1 kg air pada 100C kepada stim daripada meleburkan 1 kg ais kerana A specific heat capacity of water higher than specific heat capacity of ice muatan haba tentu air lebih tinggi dari muatan haba tentu ais B

specific heat capacity of water lower than specific heat capacity of ice muatan haba tentu air lebih rendah dari muatan haba tentu ais

C

specific latent heat of vaporization of water higher than specific latent heat

fusion of ice haba pendam tentu pengewapan air lebih tinggi dari haba pendam tentu pelakuran ais D

specific latent heat of vaporization of water lower than specific latent heat of fusion of ice

of

haba pendam tentu pengewapan air lebih rendah dari haba pendam tentu pelakuran ais Answer : A Paper 2 – Structured question (Section A)

4.1 Understanding Thermal Equilibrium Aras : Menilai We can not use Laboratory thermometer to measure our body temperature. Why? Termometer makmal tidak boleh digunakan untuk mengukur suhu badan. Kenapa?

....................................................................................................................................................... Answer : There is no ‘kink’ in laboratory thermometer. Therefore the temperature will fall as soon as we remove the thermometer from the mouth & we will not be able to measure the correct temperature of the body.

4.1 Understanding Thermal Equilibrium Aras : Analisis Why is mercury used in thermometer? Mengapakah merkuri digunakan di dalam thermometer?

....................................................................................................................................... Answer : Mercury is used in thermometer because of following reasons: i) It does not stick to the walls of capillary tube. ii) Its silvery shine helps us to see temperature accurately. iii) Its expansion is uniform. iv) It does not vaporize easily.

4.1 Understanding Thermal Equilibrium Aras : Aplikasi / Menilai Suppose you are given the choice in winter of using either one thick blanket or two thin blankets joined together. What would you choose & why? Anda diberi pilihan ketika musim sejuk untuk menggunakan satu selimut tebal atau dua selimut nipis yang digabungkan bersama. Yang manakah akan anda pilih dan kenapa?

.......................................................................................................................................

Answer: We prefer two thin blankets joined together because the air trapped between two blankets acts as an insulator and does not allow the body heat to escape.

4.1 Understanding Specific Latent Heat Aras : Menilai Why does 100°C steam is more injurious to the skin than boiling water? Mengapakah 100°C wap akan menyebabkan kecederaan yang lebih teruk kepada kulit daripada air mendidih?

....................................................................................................................................... Answer : The boiling point of water is 100 degrees Celsius. At this temperature the water will begin to change from the liquid state to the gas state. In order for this change to take place, additional energy is required. In fact, every kg of liquid water requires 2.26x106 Joules of heat energy just to convert it to steam. This is called the Lantent Heat of Vaporization. During the conversion process, temperature does not increase. It is, therefore, possible to have both liquid water and steam that exist at 100 degrees Celsius. While they both would exist at the same temperature, the steam would have a lot more heat energy due to the additional 2.26x10 6 Joules per kilogram of heat energy that has been absorbed.

4.4 Understanding Gas Law Aras : Aplikasi, Analisis, Menilai Diagram 7 shows the apparatus which can be used to investigate the relationship between the temperature and pressure for a fixed volume of gas. The reading of the pressure gauge is shown in the Table 1. Rajah 7 menunjukkan peralatan yang digunakan untuk menyiasat hubungan antara suhu dan tekanan bagi gas pada isipadu tetap. Bacaan jangka tekanan ditunjukkan dalam Jadual 1. Bourdon gauge Thermometer

Tolok bourdon

termometer

Water Air

Round bottom flask Kelalang bulat

Rubber tube beaker Tiub getah bikar Air udara

Diagram 7 / Rajah 7 Temperature / suhu ( o C)

Pressure / Tekanan( kPa)

0

103.0

100

250.6 Table 1 / Jadual 1

(a)

State why the pressure of gas is not zero when the temperature is 0 ⁰C. Nyatakan mengapa tekanan gas tidak sama dengan sifar apabila suhu 0 ⁰C. ............................................................................................................................ ...........................................................................................................................

(b) (i) The initial pressure in a car tyre is 200 kPa and the temperature of the air in the tyre is 27 ⁰C. After a long journey, the temperature of the air in the tyre increases to 85 ⁰C. Calculate the air pressure in tyre after the journey. Tekanan awal dalam tayar kereta ialah 200 kPa dan suhu udara dalam tayar ialah 27 ⁰C. Selepas perjalanan yang jauh, suhu udara di dalam tayar bertambah kepada 85 ⁰C. Hitung tekanan udara dalam tayar selepas perjalanan.

(ii) The optimum operating pressure of the tyres of a particular car is 240 kPa. Suggest the recommended pressure to be pumped to the tyres before the journey. Give one reason. Tekanan tayar yang paling optimum untuk sesebuah kereta ialah 240 kPa. Cadangkan tekanan yang bersesuaian untuk di pam ke dalam tayar sebelum memulakan perjalanan. Berikan satu sebab. Suggestion / cadangan: ............................................................................................................................ Reason / sebab: ............................................................................................................................ Answer : a) The air molecules are still in motion // still collide with each other // still collide with the wall b)

(i) T1 = 27 + 273 = 300 K // T2 = 85 + 273 = 358 K

200 P2  300 358 P2 = 238.67 kPa (ii)Less than 240 kPa According to Pressure law, Pressure increases when temperature increases // Pressure is

directly proportional to absolute temperature. Therefore, as the car moving,

temperature

inside the tyre will increase, thus the pressure of the tyre will increase.

Paper 2 – Essay question (Section B) 4.2 Understanding Specific Heat Capacity Aras : Mencipta / Aplikasi A chef has to cook for a banquet and he has to be able to prepare his food quickly, with the minimum cost yet without compromising on the quality of the food served. Seorang chef diminta memasak untuk satu jamuan dan dia perlu menyediakan makanan dalam masa yang singkat, namun tidak mengurang kualiti makanan yang dihidangkan. Using the appropriate physics concepts, suggest and explain suitable designs or ways to have a pot with the following features: Menggunakan konsep-konsep fizik yang sesuai, cadang dan terangkan rekabentuk atau kaedah yang sesuai dilakukan untuk menghasilkan periuk yang mempunyai ciri-ciri berikut:

(i) long lasting and safe tahan lama dan selamat (ii) portable mudah alih (iii) consume little fuel/cooking gas menggunakan hanya sedikit bahan api / gas memasak (iv) versatile (adaptable for various purpose: cooking, steaming and etc) pelbagai (boleh diubah sesuai untuk pelbagai tujuan : memasak, mengukus dan lain-lain)

Answer : Designs or ways

Explanation

Made from material with low

Temperature in the pot can be increased

specific heat capacity

quickly when heated. This saves fuel / cooking gas.

Made from a low density

Pot is light and more portable.

material Made from material that is not

Pot is more durable and will not contaminate

easily corroded or oxidized

the food with dangerous material.

The handle of the pot is made

The handle becomes hot slower and can be

from the material with high

held without scorching the hand.

specific heat capacity The pot is designed to have

This makes the pot versatile because

vertical compartments which

different food can be cooked at the same

can be added or removed

time.

Paper 3 – Experiment (Section B) 4.4 Understanding Gas Law Aras : Aplikasi, Analisis, Mencipta Diagram 4.1 shows three balloons which were blown and tied to a string in the early a sports day. Diagram 4.2 shows the appearance of the same balloons

morning for

during the hot afternoon.

Rajah 4.1 menunjukkan tiga belon yang diisi dengan angin dan diikat pada awal pagi untuk hari sukan. Rajah 4.2 menunjukkan bentuk belon-belon tersebut semasa tengahari yang panas.

Diagram 4.1 / Rajah 4.1

Diagram 4.2 / Rajah 4.2

Observe the shape of the balloons in both situations. Perhatikan bentuk belon-belon tersebut dalam kedua-dua situasi itu. Based on the observations :

Berdasarkan pemerhatian di atas: (a)

state one suitable inference nyatakan satu inferens yang sesuai.

(b) state one suitable hypothesis that could be investigated. nyatakan satu hipotesis sesuai yang boleh disiasat. (c)

With the use of apparatus such as a capillary tube closed at one end with some air trapped in it with a small column of oil, a tall beaker, a tripod stand and gauze, a retort stand and other apparatus, describe an experiment to investigate the hypothesis stated in 4(b). Menggunakan peralatan seperti tiub kapilari yang tertutup di satu hujungnya dengan udara yang terperangkap oleh satu turus kecil minyak, satu bikar tinggi, tungku kaki tiga dan

dawai kasa, kaki retot dan peralatan,lain, terangkan satu eksperimen untuk

menyiasat hipotesis yang dinyatakan di 4(b). In your description, state clearly the following; Didalam penjelasan anda, nyatakan dengan jelas yang berikut (i)

The aim of the experiment Tujuan eksperimen

(ii) The variables in the experiment Pembolehubah yang terlibat dalam eksperimen (iii) The list of apparatus and materials Senarai radas dan bahan (iv) The arrangement of the apparatus Susunan radas (v) The procedure used in experiment. Describe how to control the manipulated variable and how to measure the responding variable. Prosedur yang digunakan dalam eksperimen. Terangkan bagaimana mengawal pembolehubah dimanipulasikan dan bagaimana mengukur pembolehubah bergerakbalas. (vi) The way to tabulate the data. Cara untuk menjadualkan data. (vii) The way to analyze the data. Cara untuk menganalisa data. Answer : Question number (a)

Suggested answer State a suitable inference

The volume of gas depends on temperature. / the temperature affects volume (b)

State the hypothesis The higher the temperature , the bigger the volume. (correct direction)

(c)

State the aim of the experiment To investigate the relationship between the temperature and volume for a fixed mass of gas. Manipulated variable : Temperature, T Responding variable : Volume, V Constant variable : Gas pressure , P // mass of gas, m List of appropriate apparatus and material Beaker, stirrer , Bunsen burner*, capillary tube, tripod stand, thermometer*, ruler.

*must state both Arrangement of the apparatus : Set up of apparatus is functional Method to control the manipulated variables - Heat up the water with Bunsen burner slowly and stir the water until temperature reach 30 0C. Method to measure responding variables - Measure the length of the air trapped inside the capillary tube. Repeated experiment at least 4 times for manipulated variables - Repeat the experiment by continuously heat up the water until the temperature reach 400C, 500C, 600C and 700C Tabulation of data : Temperature Temperature, Volume, ,

T/K

T/ 0C

V/cm3 //Length, l/cm

30 40

50 60 70 Analysis of data A graph of Volume, V/cm3 against , Temperature, T/K is plotted V/cm3

T/K

CHAPTER 5 : LIGHT 5.1 Understanding Reflection of Light Aras : Aplikasi Ahmad is moving with speed 2 m s-1 towards a plane mirror. Ahmad and his image will approach each other at speed... Ahmad bergerak kea rah cermin dengan laju 2 m s-1 . Ahmad dan imejnya akan mendekati satu sama lain dengan laju... A. 1 m s-1 B. 2 m s-1 C. 3 m s-1 D. 4 m s-1 Answer: D

5.1 Understanding Reflection of Light Aras : Aplikasi Diagram below shows two cars, P and Q, travelling in the opposite directions, passing through a sharp bend. Rajah dibawah menunjukkan dua kereta, P dan Q bergerak dari arah yang berbeza, melalui selekoh tajam Which mirror is the most suitable to be placed at X so that the driver in car P can see car Q? Cermin manakah yang paling sesuai untuk diletak di X supaya pemandu kereta P dapat melihat kereta Q?

A

B

C

D

Answer : C 5.3 Understanding Total Internal Reflection Aras : Analisis The critical angle of a type of coloured liquid is 48. Which diagram shows the total internal reflection?

Sudut kritikal untuk cecair berwarna ialah 48 0. Rajah yang manakah menunjukkan fenomena pantulan dalam penuh.

A

B

C

D

Answer : B

5.1 Understanding Lenses Aras : Aplikasi / Mencipta A student is given three convex lenses of focal lengths 2 cm, 10 cm and 50 cm. He wishes to construct a powerful astronomical telescope. Which of the following arrangements should he choose? Seorang pelajar mempunyai tiga kanta cembung yang mempunyai panjang fokus 2 cm, 10 cm, dan 50cm. Dia ingin membina teleskop astronomi. Antara yang berikut, gabungan yang manakah perlu dipilih?

Focal length of objective lens /

Focal length of eye lens / cm

Panjang fokus kanta mata / cm

cm Panjang fokus kanta objektif / cm A

50

2

B

10

10

C

2

50

D

50

10

Answer : A

5.1 Understanding Reflection of Light Aras : Analisis Four point objects A, B, C and D are placed in front of a plane mirror MN as shown. Between their images, which can be seen by the eye?

M

N

Eye A

B

D

C

Answer :

image A

image B

image C

M

image D

N

Eye A

B

C

D

Only image D can be seen because the line joining image D to the eye cuts the actual mirror

Paper 2 – Structure (Section A) 5.2 Understanding Refraction of Light

Aras : Menilai, Analisis, Aplikasi Diagram 7.2 shows a man shooting a fish as seen by him in water. His shooting does not hit the fish. Rajah 7.2 menunjukkan seorang lelaki menembak seekor ikan yang diperhatikannya di dalam air. Tembakannya tidak mengena ikan tersebut.

Diagram 7.2 Rajah 7.2 (a) Give one reason why his shooting fails to hit the fish. Beri satu sebab mengapa tembakannya tidak mengena ikan tersebut.

................................................................................................................................ On Diagram 7.2, Pada Rajah 7.2, (b) draw two light rays to determine the actual position of the fish. lukis dua sinar cahaya untuk menentukan kedudukan sebenar ikan itu. (c) mark with X the actual position of the fish. tanda dengan X kedudukan sebenar ikan itu. (d) Give one suggestion how to shoot the fish accurately. Beri satu cadangan bagaimana untuk menembak ikan dengan tepat ................................................................................................................................ Answer : (a) Because he shoots at the image of the fish (b)

(c) He should shoot a few cm below the image of the fish

5.3 Understanding Total Internal Reflection Aras : Menilai, Analisis 1. Diagram 5.1 and Diagram 5.2 show a light ray passing through prism P and prism Q respectively. Prism P and prism Q are made of glass with different densities. Rajah 5.1 dan rajah 5.2 menunjukkan satu sinar cahaya melalui prisma P dan Q. Prisma P dan Q diperbuat daripada kaca yang berbeza ketumpatan

(a) Explain why the light ray does not bend when it enters both prisms at point A. Jelaskan mengapa sinar cahaya tidak bengkok semasa memasuki kedua-dua prisma di titik A …………………………………………………………………………………………… (b) (i) Based on Diagram 5.1 and Diagram 5.2, how can the angle of incidence at point B be made equal critical angle? Berdasarkan rajah 5.1 dan 5.2, bagaimanakah sudut tuju di titik B dijadikan sama dengan sudut genting? Prism P / Prisma P

:

……………………………………………………………………………………… Prism Q / Prisma Q

:

……………………………………………………………………………………… (ii) Diagram 5.1 shows the light ray passing from glass to air at point B. Compare the density of glass with the density of air.

Rajah 5.1 menunjukkan sinar cahaya itu merambat dari kaca ke udara di titik B. bandingkan ketumpatan kaca dengan ketumpatan udara. ………………………………………………………………………………………

Answer : (a) The angle of incidence is zero which parallel to normal causing the angle of reflection to be zero (b) i) Prism P : Increase the angle of incidence (more than 450) Prism Q : Reduce the angle of incidence (less than 450) ii) Glass is denser than air

5.3 Understanding Lenses Aras : Aplikasi An astronomical telescope consist of two thin lens set 36cm apart and has a magnifying power 8. Calculate the focal length for both lens. Sebuah teleskop astronomi mempunyai dua kanta nipis yang jaraknya ialah 36 cm dan kuasa pembesaran ialah 8. Kira panjang focus untuk kedua-dua kanta itu

Answer : Magnification = Focal length of objective lens, f0 Focal length of eyepiece, fe 8 = f0 / fe fo = 8 fe f0 + fe = 36

--------------------1

---------------------2

Put equation 1 into 2, 8 fe + fe = 36 fe = 4 cm f0 = 32 cm Paper 2 – Essay Question (Section B)

5.3 Understanding Lenses Aras : Mencpita / Aplikasi Diagram 9.4 shows a ray diagram of a slide projector. Rajah 9.4 menunjukkan gambarajah sinar sebuah projektor slaid. Condenser

Projector lens

Kondenser

Concave mirror

Slide

Cermin cekung

Slaid

Screen Skrin

Kanta projektor

Light source Sumber cahaya

The slide projector is needed in your school hall. You are required to modify the slide projector so that it can produce clearer image and can be seen by 800 students. Suggest and explain based on the following aspect:

Projektor slaid ini diperlukan untuk penggunaan dalam dewan sekolah. Anda diperlukan untuk mengubahsuaikan projektor itu untuk menghasilkan imej yang lebih jelas dan boleh dilihat oleh 800 orang pelajar. Cadang dan terangkan berdasarkan aspek-aspek berikut:

(i) The power of the bulb used. Kuasa lampu mentol yang digunakan. (ii) The position of the bulb from the concave mirror. Kedudukan bagi mentol dari cermin cekung. (iii) The curvature of the concave mirror. Kelengkungan cermin cekung. (iv) The position of the slide from the projector lens. Kedudukan slaid dari kanta projektor.

Answer : Use higher power bulb

Higher intensity of light / more light produced.

The filament of the bulb is at the

The light ray focuses to one point.

focus point of the concave mirror More curvature

Increase the intensity.

lens between f and 2f

To produce real and enlarge / bigger

images. Increase the distance / further away

Larger image produced

the screen Paper 2 – Essay Question (Section C) 5.3 Understanding Total Internal Reflection Aras : Analisis , Aplikasi

Diagram 11.2 shows an endoscope which depends largely on optical fibres for its function in showing the inside of an organ. It is able to provide light for illumination and the image can be seen through a flexible lens-telescope. Rajah 11.2 menunjukkan sebuah endoskop yang bergantung pada gentian optik untuk berfungsi dalam menunjukkan bahagian dalaman suatu organ. Ia mampu membekalkan cahaya penerangan dan imejnya boleh dilihat melalui sebuah teleskop kanta boleh lentur.

Diagram 11.2 Rajah 11.2

Optical fibres Gentian optik

Features of optical

Flexibility of

fibres

fibres

Ciri-ciri gentian

Kelenturan

optik

gentian

A few thick fibres P

Beberapa gentian tebal Single fine fibre

Q

Gentian halus tunggal A few fine fibres Beberapa gentian

R

halus

High Tinggi

Strength against breaking

terhadap

Nisbah

pemutusan

ni n0

High

Greater than 1

Tinggi

Lebih besar daripada 1

Very high

Sangat tinggi

Sangat tinggi

Sangat tinggi

ni n0

Kekuatan

Very high

Very high

Ratio

Greater than 1 Lebih besar daripada 1 Greater than 1

Very high

Lebih besar

Sangat tinggi

daripada 1

S

Single thick fibre

High

High

Gentian tebal tunggal

Tinggi

Tinggi

High

Very high

Tinggi

Sangat tinggi

A few fine fibres Beberapa gentian

T

halus

Greater than 1 Lebih besar daripada 1

Smaller than 1 Lebih kecil daripada 1

ni = refractive index of the inner core

no = refractive index of the outer cladding

indeks biasan bagi teras dalam

indeks biasan bagi pembalut luar

Table 11.1 Jadual 11.1

You are required to choose the most suitable optical fibre for use in the endoscope. Explain the suitability each characteristics of the optical fibres listed in Table 11.1 and determine the most suitable optical fibre to be used in in the endoscope. Give reasons for your choice. Anda dihehendaki untuk memilih gentian optik yang paling sesuai digunakan dalam endoskop itu. Jelaskan kesesuaian ciri-ciri gentian optik yang disenaraikan dalam Jadual 11.1 dan tentukan gentian optik yang paling sesuai digunakan dalam endoskop itu. Berikan sebab-sebab bagi pilihan anda.

Answer : 1. The cable should consist of a few fine fibres in a bundle - More signals can be transmitted separately at the same time 2. The fibres should have very high flexibility - So that it can be bent to move into difficult position easily 3. The fibres should have good strength against breaking - Could withstand vigorous and repeated bending without breaking to maintain the transmission of signals 4. The refractive index ratio of

ni >1 no

- Repeated total internal reflections can occur in the fibres 5. The most suitable fibre is R because

- It is consisted of a few fine fibres , very flexible, difficult to break and refractive ratio is

ni >1 no

Paper 3 (Section B)

5.3 Understanding Lenses Aras : Analisis , Aplikasi, Mencipta A student used a slide projector to produce an image on the screen. Diagram 1.1 and Diagram 1.2 show the relative positions of the slide, projector lens and the screen. It is observed that when the projector lens is moved nearer to the slide as shown in Diagram 1.2, the screen has to be moved further away from the slide to obtain a sharp image. Seorang pelajar menggunakan projektor slaid untuk menghasilkan imej pada skrin. Rajah 1.1 dan Rajah 1.2 menunjukkan kedudukan slaid, kanta projektor dan skrin. Adalah diperhatikan apabila kanta projektor digerakkan mendekati slaid seperti pada Rajah 1.2, skrin perlu digerakkan lebih jauh daripada slaid untuk mendapatkan imej yang tajam. Projector lens Kanta projektor Screen Skrin

Inverted Slide Slaid songsang Image Imej

Diagram 1.1 / Rajah 1.1

Projector lens Kanta projektor Inverted Slide Slaid songsang

Screen Skrin Image Imej

Diagram 1.2 / Rajah 1.2

Based on the information and observation: Berdasarkan maklumat dan pemerhatian tersebut: (a) State one suitable inference / Nyatakan satu inferens yang sesuai

(b) State one hypothesis / Nyatakan satu hipotesis yang sesuai (c) With the use of apparatus such as convex lens, filament bulb and other apparatus , describe one experiment to investigate the hypothesis stated in 3(b). Dengan menggunakan radas seperti kanta penumpu, mentol filamen dan lain-lain radas, terangkan satu eksperimen untuk menyiasat hipotesis yang dinyatakan dalam 3(b). In your description, state clearly the following: Dalam penerangan anda, jelaskan perkara berikut: (i)

The aim of the experiment. / Tujuan eksperimen.

(ii) The variables in the experiment./ Pembolehubah dalam eksperimen. (iii) The list of apparatus and materials. / Senarai radas dan bahan. (iv) The arrangement of the apparatus. / Susunan radas. (v) The procedure used in the experiment which should include one method of controlling the manipulated variable and one method of measuring the responding variable. Prosedur eksperimen yang mesti termasuk satu kaedah mengawal pembolehubah dimanipulasikan dan satu kaedah mengukur pembolehubah bergerak balas. (vi)

The way to tabulate the data. / Cara untuk menjadualkan data.

(vii) The way to analyse the data. / Cara untuk menganalisis data.

Answer : 3a

The image distance /size of image / height of image / magnification depends on the object distance

b

The greater the object distance, the smaller the image distance / size of image / height of image / magnification

c( i)

Aim of the experiment To investigate the relationship between object distance and image distance / size of image / height of image / magnification for a convex lens.

(ii)

Variables in the experiment

Manipulated variable : object distance Responding variable : image distance / size of image / height of image / magnification Fixed variable : (iii)

Focal length of lens / thickness of lens / power of lens

List of apparatus and material light bulb, convex lens of focal length 10 cm , white screen, metre rule, low voltage power supply and lens holder

(iv)

Arrangement of apparatus

Image distance

Object distance bulb

lens

screen

Meter rule Lens holder Low voltage power supply

(v)

V

The apparatus set up as in figure shown. Adjust the bulb so that the object distance (filament), u is 35 cm from the lens.

Light up the electric bulb, adjust the screen position until a sharp image of the filament is formed on the screen. Record the image distance, v. / height of image // calculate magnification, m = v/u Repeat steps 2 and 3 for objects distances of, u = 30cm, 25 cm, 20 cm, and 15 cm. (vi)

How you tabulate the data.

object distance, u /

Image distance, v / cm /

cm

height of image , cm / Magnification

35 30 25 20 15 (vii)

How you analyse the data.

Image distance / height of image , cm / Magnification

Object distance

CHAPTER 6 : WAVE 6.3 Analyzing Refraction of Waves Aras : Aplikasi Diagram 21 shows a house at the bottom of a hill received a radio waves from a transmission station. Rajah 21 menunjukkan sebuah rumah di kaki bukit menerima gelombang radio daripada stesen pemancar. Hill Bukit

Transmission station Stesen pemancar

House Rumah

Diagram 21 Rajah 21 This happens because the radio waves is being Ini berlaku disebabkan oleh gelombang radio A

diffracted dibelau

B

refracted dibias

C

reflected dipantul

D

dispersed diserak

Answer : A

6.3 Analyzing Electromagnetic Waves Aras : Analisis Which of the following waves cannot travel through vacuum? Manakah antara gelombang berikut yang tidak boleh bergerak di dalam vakum? A. Sound waves Gelombang bunyi B. X-rays x-ray

C. Radio waves Gelombang radio D. Light wave Gelombang cahaya Answer : A Paper 2 – Structure (Section A)

6.3 Analyzing Diffraction of Waves Aras : Menilai Why is diffraction effect more predominant through the slit formed by two blades than by slit formed by two fingers? Mengapakah pembelauan lebih jelas jika ia melalui dua celah yang dihasilkan daripada pisau daripada dua celah yang dihasilkan daripada jari?

.......................................................................................................................................

....................................................................................................................................... Answer : Diffraction effect is predominant only for a narrow & fine slit where size is comparable with the wavelength of light. Slit formed by two blades is fine & is of uniform width which can't be possible with fingers.

6.3 Analyzing Interference of Waves Aras : Menilai , Mencipta a) Why is light from two individual sources of equal wavelength is incoherent? Mengapakah cahaya dari dua sumber yang berbeza tetapi mempunyai panjang gelombang yang sama tidak koheren?

.................................................................................................................. b) How to produce a two coherent source of light? Bagaimanakah untuk menghasilkan dua sumber cahaya yang koheren?

................................................................................................................ Answer: a)

Because of unstable phase difference.

b) By having a light source to pass through a double slit

6.1 Understanding Waves

Aras : Menilai , Mencipta

Figure 2 A ping pong ball is held with a string and placed near a loudspeaker as shown

in Figure 2

The loudspeaker emits a low frequency sound and the ping-pong ball seems to vibrate to it. Sebuah bola ping pong di ikat dan diletakkan berdekatan dengan pembesar suara seperti dalam rajah 2 di atas. Pembesar suara itu menghasilkan frekuensi yang rendah dan bola ping pong mula bergetar. (a) Explain how the sound from the loudspeaker produces vibration on the ping pong ball. Terangkan bagaimana bunyi dari pembesar suara boleh menyebabkan bola ping pong itu bergetar

............................................................................................................................................. (b) Predict what will happen to the vibration of the ping pong ball if the loudspeaker emits Apakah yang akan terjadi kepada getaran bola ping pong itu jika pembesar suara menghasilkan (i) a louder sound? bunyi yang kuat?

............................................................................................................................................. (ii) a sound with a higher pitch? bunyi dengan kenyaringan yang tinggi?

............................................................................................................................................. (c) If the frequency of the sound is 50 Hz, calculate the wavelength of the sound produced. [Assume the speed of the sound in air in 350 ms-1] Jika frekuensi bunyi itu 50 Hz, kira panjang gelombang bunyi yang dihasilkan [Andaikan laju bunyi di udara ialah 350 ms-1]

Answer : (a) The vibration of the loudspeaker moves the air molecules around it. The sound wave produced by the loudspeaker transfers energy to the ping pong ball and causes it to move (b) (i) The ping pong ball vibrates with greater amplitude (ii) The ping pong ball vibrates with higher frequency. (c)

=

v f

=

350 = 7m 50

Paper 2 – Essay question (Section B) 6.3 Analyzing Diffraction of Waves Aras : Mencipta, Aplikasi

Diagram 10.3, shows the location of housing area. The residents of housing area at P receive clearer television signal compare to the residents of housing area at Q where it is located behind the hill. Rajah 10.3, menunjukkan kedudukan kawasan perumahan. Perumahan di kawasan P menerima isyarat television lebih jelas berbanding dengan penduduk di kawasan perumahan Q di mana kedudukannya adalah di belakang bukit. Broadcasting station Stesyen penyiaran

Transmitter Pemancar

Housing area Q

Housing area P Kawasan perumahan P

Hill

Kawasan perumahan Q

Bukit

Diagram 10.3 /Rajah 10.3 As a researcher, you are required to give suggestions about the modifications of television signal from broadcasting station so that the residents of housing area at Q are enable to receive better signal. Sebagai seorang pengkaji, anda diperlukan untuk memberikan beberapa cadangan mengenai pengubahsuaian isyarat television daripada stesyen penyiaran bagi penduduk di kawasan perumahan Q menerima isyarat yang lebih baik.

State and explain the modification based on the following aspects: Nyata dan terangkan pengubahsuaian berdasarkan aspek-aspek berikut:

(i)

the frequency of the signals / frekuensi isyarat

(ii)

the location of the transmitter / kedudukan pemancar

(iii)

the number of the transmitter / bilangan pemancar

(iv) (v)

the strength of the signals / kekuatan isyarat the distance between two transmitters / jarak antara dua pemancar

Answer : Modification

Reason

Frequency of signal is

Longer wavelength/ diffraction easier

low The location of

no blocking / capture more signal

transmitter higher the number of

increase the strength of signal/ increase energy of signal

transmitter is more /

/

many

reduce energy lost during transmission

The strength of signal is

have more energy / can move further

higher The distance between

increase the strength of signal/ increase energy of signal

two transmitter is closer

Paper 3 (Section B)

6.3 Analyzing Interference of Waves Aras : Mencipta, Aplikasi, Analisis

P

Q

R

Diagram 4 / Rajah 4 Diagram 4 shows an audio technician checking and testing the audio system in a mini theatre by changing his seating positions. Clear and loud sound can only be obtained at seating positions P and Q which is equals to 4 seatings away from each other with a certain distance from the loudspeakers. When he moves further away from the loudspeakers, the clear and loud sound can only be heard between Q and R which is equals to 6 seatings away from each other. Rajah 4 menunjukkan pegawai teknik audio sedang memeriksa dan menguji sistem audio di dalam teater mini dengan mengubah

posisi tempat duduknya. Bunyi jelas dan kuat

kedengaran pada posisi P dan Q yang bersamaan dengan jarak 4 buah kerusi antara satu sama lain pada suatu jarak tetap dari pembesar suara. Apabila pegawai itu bergerak lebih jauh dari pembesar suara itu, bunyi jelas dan kuat hanya kedengaran pada posisi Q dan R yang bersamaan dengan jarak 6 buah kerusi antara satu sama lain.

Based on the information and observation: Berdasarkan maklumat dan pemerhatian tersebut:

(a) State one suitable inference / Nyatakan satu inferens yang sesuai. (b) State one hypothesis / Nyatakan satu hipotesis yang sesuai (c)

With the use of apparatus such as audio generator, loudspeakers and other apparatus, describe one experiment to investigate the hypothesis stated in Dengan menggunakan radas seperti penjana audio, pembesar suara dan lain-lain radas, terangkan satu eksperimen untuk menyiasat hipotesis yang dinyatakan di4(b). In your description, state clearly the following: Dalam penerangan anda, jelaskan perkara berikut:

(i)

The aim of the experiment. / Tujuan eksperimen.

(ii) The variables in the experiment./ Pembolehubah dalam eksperimen. (iii) The list of apparatus and materials. / Senarai radas dan bahan. (iv) The arrangement of the apparatus. / Susunan radas. (v) The procedure used in the experiment which should include one method of controlling the manipulated variable and one method of measuring the responding variable. Prosedur eksperimen yang mesti termasuk satu kaedah mengawal pembolehubah dimanipulasikan dan satu kaedah mengukur pembolehubah bergerak balas. (vi)

The way to tabulate the data. / Cara untuk menjadualkan data.

(vii) The way to analyse the data. / Cara untuk menganalisis data.

Answer : (a)

The distance between two successive positions of clear and loud sound depends on the distance of the loudspeakers and the position of technician.

(b)

The distance between two successive loud sounds, x, increases when the distance between the loudspeakers and position of the technician, D, increases.

Jumlah (c)(i)

Aim: To investigate the relationship between distance, x, and D.

Manipulated variable: Distance between loudspeakers and position of (ii)

technician, D Responding variable: Distance between two successive positions of loud sound, x Constant/fixed variable: Distance between the two loudspeakers / frequency of sound wave.

List of apparatus: (iii)

Audio signal generator, two (identical) loudspeakers, connecting wires, metre rule or measuring tape.

Arrangement of apparatus: (iv)

Audio Signal Generator

Loudspeaker a L= Loud sound

D x L

Position of technician L

L

1. The apparatus is set up with the two loudspeakers placed apart at a (v)

distance , a = 1.0 m as shown in the diagram. 2. The observer will stand at a distance, D = 5 m, from the speakers. 3. The audio generator is switched on and set at a frequency, f = 600 Hz. 4. The observer will move along a parallel straight line at a distance D = 5.0

m from the loudspeakers.

5. The positions of loud sound that can be heard are marked as L. 6. Distance between 2 successive loud sound, x is measured using a metre rule and recorded. 7. The experiment is repeated with different values of D which is 10 m, 15 m, 20 m and 25m. 8. All the readings are tabulated.

Tabulate the data (vi)

D (m)

x (m)

5.0 10.0 15.0 20.0 25.0 Analysis of data (vii)

x (m)

D (m) A graph of x against D is drawn to analyse the data.