GRADE 9

PHYSICAL SCIENCE

NOVEMBER 2014

MARKS: 120 TIME: 2 HOURSEXAMINER: KW MODERATOR: KK

General Instructions:

1. Answer ALL the questions.

2. Question 1: Follow the instructions for writing your answers.

3. Calculations: Show your workings – clearly and logically and give your answers correct to two decimal places.

4. Refer to the attached data sheet where necessary.

Question 1: Multiple Choice

Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Write only the letter (A – D) next to the question number (1.1 – 1.10) for example 1.11 D.

1.1 The particle in the atom which does not have an electric charge.

A) Electron

B) Nucleus

C) Proton

D) Neutron

1.2 The name of the group of elements which all have a valency of -1.

A) Halogens

B) Alkali metals

C) Alkali-earth metals

D) Noble gases

1.3 The type of bonding which results in the formation of SALTS.

A) covalent

B) metallic

C) ionic

D) co-ordinate

1.4 Waves bend towards the normal line when entering a more optically dense medium at an angle because…

A) the waves move slower in this new medium

B) the wavelength of the waves increase in this new medium

C) the waves move faster in this new medium

D) the waves have greater amplitude in this new medium

1.5 Sharply defined shadows result from…

A) diffuse reflection of light off rough surfaces

B) rectilinear propagation of light

C) diffraction of light

D) refraction of light

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1.6 The hydrostatic pressure (pressure due to the water) on a swimmer’s ears 1 m below the surface of the sea would be…

A) greater than the pressure 1 m deep in a salt water swimming pool

B) the same as the pressure 1 m deep in a salt water swimming pool

C) less than the pressure 1 m deep in a salt water swimming pool

D) the pressure would depend on the direction in which the swimmers ears were pointed

1.7 A positively charged rod is brought close to (but does not touch) the plate of an electroscope and the gold leaf rises to a horizontal position as shown.

This is because…

A) electrons are repelled to the bottom of the electroscope.

B) protons are attracted to the top of the electroscope.

C) the bottom of the electroscope becomes positively charged.

D) excess electrons are transferred onto the electroscope.

1.8 Two 3V cells are connected in parallel together to form the energy source for a circuit. Their combined potential difference will be…….

A) 2 V

B) 6 V

C) 1.5 V

D) 3 V

1.9 Bulbs W, X, Y and Z are identical. Which bulb/s will be the brightest when the switch is open?

A) W

B) X

C) Y

D) Z

1.10 Which of the following statements about acids is incorrect?

A) All acids release hydrogen ions in water.

B) All acids contain the element hydrogen.

C) All acids react with bases to form salts.

D) All compounds containing hydrogen are acids.

10 X 2 = [20]

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Question 2: Atomic structure, bonding and The Periodic table.

When two or more atoms combine chemically we refer to this combination of atoms as a molecule.

2.1 Draw a Lewis diagram of a water molecule. (3)

2.2 Describe how two isotopes of an element are;

2.2.1 similar (2)

2.2.2 different (1)

2.3 When sodium metal is placed in water the following reaction takes place:

sodium + water hydrogen + sodium hydroxide

2.3.1 Write the question numbers 2.3.1.1 – 2.3.1.4 and the missing information for each substance next to the appropriate question number on your answer paper. One substance is completed for you as an example. (4)

SUBSTANCE ELEMENT / COMPOUND BONDING

sodium element metallic

water compound 2.3.1.1

hydrogen 2.3.1.2 covalent

sodium hydroxide 2.3.1.3 2.3.1.4

2.3.2 Write a balanced chemical equation for this reaction. (4)

[14]

Question 3: Waves and Sound

Sound is an example of wave motion which we come into contact with every day.

3.1. What type of wave is a sound wave, transverse or longitudinal? (1)

3.2 Which property of a sound wave relates to its volume (loudness)? (1)

3.3 In an experiment to determine the speed of sound in air, pupils find that the average time taken for them to hear an echo of their clapping returning from the wall of a large building a certain distance away from them is 0,361s.

3.3.1 Assuming the speed of sound to be 340.0 m.s-1, calculate the distance from the pupils to the building. (3)

3.3.2 If the frequency of sound which they used to determine the speed of sound was 342Hz, calculate the wavelength of this sound wave. (3)

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Question 4: Light, lenses and colour

An engineer proposes a design for a colour multifunction scanning/photocopy/printer machine as shown below. The diagram shows how the machine would make an image of the word RED which is written in RED ink on white paper.

The arrangement shines a bright white light onto the original page which reflects through a lens onto a light sensitive plate. Sensors on the plate convert the light energy to electrical signals which are taken by an electrical cable to a printing head which prints using ink jets.

4.1 Identify the type of lens is used for this device? (1)

4.2 State whether the image formed by this lens is real or virtual. (1)

4.3 The lens can be shifted LEFT or RIGHT to enlarge or reduce the image.

4.3.1 Would the lens need to shift LEFT or RIGHT to ENLARGE the image? (1)

4.3.2 If the image was required to be reduced to a third of the size of the original, calculate the distance needed from the original page if the distance to the light sensitive plate was 30 cm. (3)

4.4 The printing is done using three different colour pigments (inks).

4.4.1 Two of the pigment colours are; magenta and cyan, what would the third pigment colour be? (1)

4.4.2 Which TWO colour pigments would the printer use in order to print the word RED in so that it appeared red in colour? (1)

4.5 One of the engineers in the team identifies one critical problem in the proposed arrangement which would prevent the device from being able to correctly print copies of words and writing. Identify this problem. (1)

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Question 5 Pressure

A number of everyday items make use of the effects of pressure in order to function like drawing pins and hydraulic jacks.

5.1 Explain how a drawing pin makes use of pressure in order to function. (2)

5.2 If a force of 50 N is exerted onto the top of a drawing pin and the area of the point is 0.1 x 10-3 m calculate the pressure exerted by the point of the pin. (3)

5.3 Name the principle which allows a hydraulic jack to function. (1)

5.4 The hydraulic jack in the picture has cylindrical pistons and is designed to lift a maximum of 20 000 N when the user exerts a force of 400 N on the small cylinder which has a surface area of 25 cm2. Calculate the required diameter of the large piston (in meters). (4)

5.5 The apparatus in the picture can be used to measure the pressure of the gas in the round jar labelled A.

5.5.1 If the liquid shown in the tube is water with a density of 1000 kg.m3 calculate the pressure in the jar A. (4)

5.5.2 Assuming that the level of the water in the two sides of the tube were level when jar A was connected, suggest what change made to jar A which could have caused the pressure observed. (1)

5.5.3 Name one other instrument which can be used to measure air pressure other than the one shown in the picture. (1)

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Drawing pins Hydraulic Jack

Question 6: Electrostatics

6.1 In a classroom experiment to determine the nature of some charged objects, a teacher has charged a balloon, a comb, a glass rod and a metal sphere on an insulated stand before the class came in.

6.1.1 Describe a simple method to charge a balloon? (1)

6.1.2 Use your knowledge of atomic structure to explain how this method works. (2)

6.1.3 If the teacher held the charged balloon near a thin flowing vertical stream of water, what would you observe? (1)

6.1.4 Explain your observation in 6.1.3. (2)

6.2 In order to determine which material holds its charge for longest the teacher wants the students to use an electroscope to test the strength of the charge at various intervals after charging them.

The electroscope is placed on an insulating stand a fixed short distance away from the charged object. The students record the time taken for the gold leaf on the electroscope to return to its uncharged position.

The students also get a measure of the strength of the charge by estimating the angle of the gold leaf on the electroscope using a transparent protractor stuck to the glass viewing window on the electroscope as shown.

6.2.1 What would be the dependent variable in this investigation?(1)

6.2.2 State one additional variable that the students would need to try and control in order to make these tests fair – other than the atmospheric (temperature, humidity, wind etc.) conditions in the laboratory. (1)

The following readings are recorded by the students:

6.2.3

shown at the end of this exam paper on a separate page.

6.2.3.1 Plot the values for the last experiment (the metal sphere) onto the supplied graph and connect them with a line of best fit. (3)

6.2.3.2 Write a suitable heading for the graph. (1)

6.2.3.3 What would the gradient or slope of these graphs represent? (1)

6.2.3.4 What conclusion can be drawn from the graphs regarding the rate of charge loss of the materials? (2)

6.3 If the metal sphere is given a charge of -1 nC and then touched briefly against an identical sphere which has a charge of +2 nC calculate the resulting charge on each sphere (in coulombs) once the spheres are separated again. (2)

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Question 7: Electricity

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Time (s)

MaterialCharge

(degrees) 1 2 3 4 5 6 7 8 9 10Rubber (balloon) 40 36 32 28 24 20 16 12 8 4 0Plastic (comb) 42 38 34 30 26 22 18 14 10 6 2Glass (rod) 30 26 22 18 14 10 6 2 0 Metal (sphere) 20 16 12 8 4 0

7.1 Draw a circuit diagram showing the following elements; three cells of 1,5V each connected in series with an ammeter and then two identical light bulbs connected in parallel. Show a voltmeter connected across one of the bulbs and an open switch breaking the circuit for the other bulb. (5)

7.2 What would the reading be on the voltmeter? (1)

7.3 Calculate the resistance of the working light bulb if the ammeter reads 0.85 A. (3)

7.4 If the switch was now closed would you expect the bulb to burn DIMMER, BRIGHTER or THE SAME as before? (1)

7.5 If the two light bulbs in the circuit above were now connected in SERIES, would they glow BRIGHTER, DIMMER or the SAME as when connected in parallel? (1)

7.6 Give a reason for your answer to 7.5 by referring to the voltage in the circuit. (2)

7.7 Perform a calculation to determine:

7.7.1 the total resistance in the circuit when both bulbs are connected in series. (2)

7.7.2 the current flowing in the series circuit. (3)

7.7.3 How long would it take for one coulomb of charge to flow through one of the bulbs?(3)

[21]

Question 8: Acids and bases

Acids and bases are compounds which have a wide range of applications in daily life.

8.1 A pupil would like to see whether the house-hold cleaner they use at home is acidic or alkaline.

8.1.1 Suggest a simple test he could perform in his school laboratory to answer his question using litmus paper. (2)

8.1.2 Give one EXAMPLE of an acid other than those mentioned in this question. Give the NAME AND FORMULA. (2)

8.1.3 Give one PHYSICAL characteristic and one CHEMICAL characteristic of a base. (2)

8.2 Indigestion can be treated with bicarbonate of soda (sodium hydrogen carbonate) to reduce the discomfort.

8.2.1 Explain why this works using acid-base theory. (2)

8.2.2 Give a reason why a person may feel the need to burp after taking bicarbonate of soda by referring to the reaction that takes place when bicarbonate of soda reacts in the stomach. (1)

8.3 A range of substances can be formed when acids react with bases.

8.3.1 Give the general word reaction for the reaction that takes place when acids react with metals. (2)

8.3.2 Give a balanced chemical equation for the reaction that takes place when pool acid (HCl) reacts with quicklime (Calcium hydroxide). (3)

8.3.3 Name the salt formed when copper oxide reacts with sulphuric acid. (1)

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Total: [120]

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Name:

Data Sheet Grade 9

The following equations may prove useful in your calculations:

Waves and Light: V = f x λ T = 1/f speed = distance / time

__________________________________________________________________________________

Pressure:

P= FA

P = d x g x h or P = ρ x g x h

__________________________________________________________________________________

Electricity: Q = I x t V = I x R Series resistors; RT = R1 + R2 + R3 + ..........

NAME SYMBOL VALUE

Speed of sound Vsound 340 m·s-1

Atmospheric pressure (1 atm) pθ 1,013 x 105 Pa

Standard temperature T θ 273 K

Gravitational acceleration g 9.8 m.s-2

Density of Mercury (Hg) (Hg) 13590 kgm-3

Density of Water (H2O) (H2O ) 1000 kgm-3

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PERIODIC TABLEI II <--GROUP NUMBERS--> III IV V VI VII 0

1 2H He1 KEY 43 4 3 5 6 7 8 9 10Li Be Li B C N O F Ne7 9 7 11 12 14 16 19 2011 12 13 14 15 16 17 18Na Mg Al Si P S Cl Ar23 24 27 28 31 32 35.5 4019 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br K r39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 8437 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe86 88 89 91 93 96 99 101 103 106 108 112 115 119 122 128 127 13155 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn133 137 139 179 181 184 186 190 192 195 197 201 204 207 209 210 210 22287 88 89

58 59 60 61 62 63 64 65 66 67 68 69 70 71

140 141 144 145 150 152 157 159 163 165 167 169 173 17590 91 92 93 94 95 96 97 98 99 100 101 102 103

232 231 238 237 239 243 247 247 252 (252) (257) (258) (259) (260)

Atomic numberSymbol

Mass number