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44. Diagram shows an athlete throwing a javelin. Using appropriate physics concepts, explain the use of suitable equipment and techniques to improve his performance. Your answer should include the following aspects:(i) Materials used for javelin. (ii) Shape of javelin

Answer

45. An efficient hydraulic brake system is very important in a car for safety purposes. Diagram shows a car hydraulic brake system.

Suggest and explain the modification should be done on the system so that it can function effectively based on the following aspects :(i) The type material of brake fluid. (ii) The characteristic of brake fluid. (iii) The size of master piston (iv) The size of slave piston. (v) The type material of the fluid transmission pipe

Modification/ suggestion ExplanationOil Incompressible/No air bubbleHigh boiling point/Low density/High viscosity

Does not change to gas state/Lighter/Less friction/Does not evaporate easily

Small master piston High pressure produced/Small force usedBig slave piston Produce big forceAluminium/Steel Strong/Does not break easily/Non corrosive/Prevent leakage/Withstand

temperature/Does not rust easily

Modification Reason Strong material Do not break easilySmall mass To increase speed / lighterStreamline Reduce air resistanceRun faster Increase kinetic energyThrow at an angle of 45 To get maximum horizontal distanceThrow with high force To get maximum horizontal distance

(iii.) Motion of the athlete (iv.)How the javelin should be thrown.

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46. An open aluminium container with some ice cubes is used to cool the packet drinks as shown in the figure.

Use appropriate concepts in physics, explain the modifications required to the above aluminium container so as to work effectively.(i) cool packet drinks in a shorter time.(ii) keep the packet drinks remain cold for a longer period.

Answer

47.Diagram 10.4 shows an electric oven is being used to heat up food which has been taken out from a refrigerator. You are required to modify the design in Diagram 10.4 by using an electromagnetic wave and a transmitter so that the food can be heat up uniformly and in a shorter time. State and explain the modification based on the following aspects:

i. The type of electromagnetic wave used ii. The position of the transmitter. iii. The material of the food tray.

Suggestions ReasonAdd more ice Large mass of ice can absorb more heat from the drinks.Add water to the ice Increase the rate of heat transferred through conduction.Container made of heat insulator To reduce heat absorbed from the surrounding.Container made of substance with high specific heat capacity

Not easily heated up.

Use white container Do not absorb heat

Modification ReasonMicrowave Energy of the microwave is converted to heatTransmitter is located at the center of the oven

The heat can be distributed uniformly to the food

The material of the food tray is made of porcelain / glass / heat resistant

Can withstand high temperature in the oven

The shape of food tray is circular So it can be rotated easily and continuously. The food can absorb heat uniformly.

The casing is made from metal Can reflect microwave

iv.The shape of the food tray. v.The material used for the oven casing

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48.Diagram 10.4 shows a cross section of a moving coil microphone.

Diagram 10.4

When the diaphragm moves in response to sound, the attached coil moves in the magnetic field and generates a very small current in the wire of the coil. Using an appropriate concept in physics, suggest and explain suitable modifications or ways to enable the microphone to detect sound more effectively and generate a bigger current based on the following aspect:-thickness of diaphragm -strength of the material for diaphragm-number of turns of coil

Answer

49. Diagram 10.3 shows a radioactive source is handled by a scientist. The method shown is not safe. Suggest and explain:(i) The equipment to be used in handling a radioactive source.(ii)Modifications to the storing method to ensure safe keeping of the

radioactive source.(iii)Other precautions that need to be taken when handling a radioactive source.

Answer

ASPECT REASONINGuse thin diaphragm Easy to vibrateUse strong material Not easy to breakMore number of turns of coil Increase the rate of change of magnetic flux linkage // The

magnitude of the induced current or is also increased Thicker diameter of wire of coil Reduce the resistance of the coilUsing more powerful magnet The magnitude of the induced current is also increased

Suggestion ExplanationUse forceps/robot The distance between the source and the body is far.Wear a mask// goggle The radiation does not penetrate our eyesUse a lead box/ container with thick concrete

To prevent radiation leakage to surroundings

Keep the exposure time as short as possible

The body is not exposed to the radiation for a long time.

Wear a film badge To detect the amount of radiation exposedPut radiation symbol on the storage box

To inform users of dangerous contents of the box.

Wear coat lined with lead To protect the body from the radiation

-diameter of the wire of coil -strength of magnet

50.Diagram 10.4 shows the screen of a cathode ray tube (CRO) with an alternating input voltage of 240 V. The CRO is connected to box P which in turn is connected to a hand phone.

Suggest and explain the suitable circuit for box P so it is suitablanswer:-the device used to charge the 9 V hand phone.-The component used to convert alternating current to direct current. (draw the complete and output).-The component used to smoothen the output voltage and how it is connected in the circuit.-Draw the final wave form obtained.

AnswerTo charge the hand phone: A step down transformer is used.Decrease input voltage from 240 V to 9 V.To convert ac to dc: Four diodes are useUse capacitor to smooth the output voltage.

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.Diagram 10.4 shows the screen of a cathode ray tube (CRO) with an alternating input voltage of 240 V. The CRO is connected to box P which in turn is connected to a hand phone.

and explain the suitable circuit for box P so it is suitable for charging the hand phone. Include in your

the device used to charge the 9 V hand phone.The component used to convert alternating current to direct current. (draw the complete -circu

The component used to smoothen the output voltage and how it is connected in the circuit.

A step down transformer is used.to 9 V.

used to form full-waved rectifier.Use capacitor to smooth the output voltage.

.Diagram 10.4 shows the screen of a cathode ray tube (CRO) with an alternating input voltage of 240 V. The

Include in your

circuit with input

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51. Diagram 11.1 shows the air balloon which is used as a weather balloon to carry a radiosonde instrument for collecting data about the atmosphere. The weather balloon rises up in the air due to ArchimedesPrinciple.

Study the specification of the four arrangement based on the following aspects: (i) the angle of the two towing boat (ii) the shape of the towing boats (iii) type of cable rope used. (iv) the elasticity of cable used. Explain the suitability of each aspect and then determine the most suitable arrangement. Give a reason for your choice.

AnswerASPECT REASONINGSmall angle Produce bigger resultant forceStreamlined shape of towing boats

Reduce resistance

Steel Rod Strong// able to withstand high tensionInelastic Produce uniform force during the towing.

Method K is chosen because it has small angle, its towing boat is streamlined, the cable rope is made of steel and inelastic.

Method L

Method M

Method J

Method K

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52.Diagram 11.2 shows four boats, P, Q, R and S, with different specifications. You are required to determine the most suitable boat that can carry many passengers, move with high speed and safe. Study the specifications of all the four boats from the following aspects.

- The material used to build the body of the boat.- The volume of the boat.- The distance of the Plimsoll line from the surface of the sea.- The size of the propeller.

Boat P Boat R

Boat Q Boat S

Explain the suitability of the above aspects and hence, determine the most suitable boat to carry heavy load and move with high speed. Justify your choice.

AnswerCharacteristics Reason

Fibre composite Light and strongBigger volume High buoyant forceThe distance between plimsoll line from the surface of the sea is high

Can carry more load

Bigger size of the propeller To produce greater forward thrustQ is choosen because the body is made from fibre composite, bigger volume (100 m3), the distance between plimsoll line from the surface of the sea is high and bigger size of the propeller.

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53.Diagram 11.3 shows a radiator used to maintain temperature of a small room so that the occupants of the room feel warm during a very cold day.

Diagram 11.3Table 11 shows the characteristics of four different radiators.

Explain the suitability of each characteristic of the radiator and determine the most suitable radiatorto be used for the purpose of maintaining the temperature of the small room. Give reasons for your choice.

AnswerCharacteristic Reason

Automatic control unit The heater will switch off if the room is very hot.Black colour of radiator source Good heat absorber and transmitterHigh boiling point of heating liquid The liquid will not change to gas easily.Low power Save energy / low costChoose Z because it has automatic control unit, black colour of radiator source, high boiling point of heating liquid and use low power.

54.Table 12 shows 5 heating elements M,N,O,P and Q with characteristics to use as an effective bread toaster heater.

You are required to determine the most suitable element heating that can be used to toast bread fast and crispy. Study the specifications of all the five heating element based on the following aspects :-Size of wire - Specific Heat Capacity -Resistance per meter -Length of the heating element Explain the suitability of each aspect and then determine the most suitable heating element.

Answer

Heating element N is chosen because its wire is small, high resistivity, low specific heat capacity and long wire.

Radiator Control unit Colour of radiator surface Boiling Point of heating liquid PowerW Automatic Silver 100 oC 3.0 kWX Manual Black 100 oC 1.5 kWY Manual Silver 300 oC 3.0 kWZ Automatic Black 300 oC 1.5 kW

Heating element Size of wire/swg Resistivity / m Specific Heat Capacity/ Jkg-1 oC-1 Length/ mM 15 2.0 x 10-8 900 2N 30 10.0 x 10-8 390 3O 15 8.0 x 10-8 450 2P 30 6.0 x 10-8 440 3Q 15 7.0 x 10-8 390 2

Characteristics ReasonSize of wire is small High resistanceResistivity is high produce more heatLow specific heat capacity Heat up fasterLong wire High resistance

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55.National Grid Network is a system of electric transmission from power station to the consumer in our country. Diagram 12.3 shows a block diagram of the system.

Using your knowledge about electrical and Diagram 12.3 , you are asked to determine the most suitable item used in the system J, K, L, M and N for a National Grid Network system in Diagram 12.4.

Diagram 12.4Study the specification of the five system and explain the suitability of each based on following aspects;

(i) type of transformer P and Q(ii) characteristic of cable used(iii) potential difference transmission of electric(iv) The position of cable

Explain the suitability of each aspects and determine the most suitable system. Give your reason for your choice.

Aspect ReasoningP step up, Q step down P to increase voltage, Q to decrease voltage to consumerBig Diameter Reduce resistanceCurrent with high voltage Small current flows //

Reduced power/ heat lossCable on pylon Safety reason L is chosen P step up Q step down, Big Diameter, Current with high voltage, Cable on

pylon

System Type of Transformer Diameter of conductor cable

Transmission voltage Cable Position

J P is step up Q is step down

Big diameter conductor

Current with Low voltage On the Pylon

K Q is step up P is step down

Small diameterConductor

Current with higher voltage On concrete piller

L P is step up Q is step down

Big diameter conductor

Current with higher voltage On the Pylon

M Q is step up P is step down

Small diameterConductor

Current with Low voltage On concrete pylon

N P is step up Q is step up

Small diameterConductor

Current with higher voltage

On concrete piller

Power stesen

Transformer P Transformer Q

Consumer

Electric CableKabel elektrik

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56.Diagram 12.2 shows four types of moving coil ammeter, R, S, T and U to measure small direct current.You are required to determine the most suitable moving coil ammeter to measure the small direct current effectively.

You are required to determine the most suitable moving coil ammeter to measure small direct current effectively.Study the specification of all the four moving coil ammeters based on the following aspects: (i) The shape of the permanent magnet and core

(ii) The material of the core (iii) The stiffness of the hair spring(iv) The type of scale of the ammeter

Explain the suitability of each aspect and then determine the most suitable moving coil ammeter. Give a reason for your choice.

Characteristics ExplanationCurved shape Produce radial magnetic fieldSoft iron Easily to magnetised and demagnetisedSoft spring Can detect small current // more sensitive // can measured small currentLinear scale Uniform deflection // force produced directly proportional to current.T is chosen Curved shape, Soft iron , soft spring and linear scale

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57.As a scientist, you are asked to investigate the characteristics of radioisotopes J, K, L and N that could be used to detect the thickness of paper in a paper factory. Table 12 shows the characteristics of the radioisotopes.

Radioisotopes State of matter Type of ray Half-life Penetrating powerJ Solid Beta 12 years MediumK Solid Gamma 5 years HighL Solid Alpha 19 days LowN Gas Beta 5 years high

Using Table 12, describe the characteristics of radioisotope that is suitable to be used in the paper thickness detection system. Determine the most suitable radioisotope to be used to detect the paper thickness and give your reasons.

AnswerCharacteristics reason

Solid Easy to handleBeta Can penetrate the paperLong half life Do not need to replace the radioactive substance frequently, save costMedium Suitable to use to measure thickness of paper / reduce danger o radiation to

people / no extra shielding neededChoose J because it is solid, emit Beta, long half-life, medium penetration power

58.Diagram shows a canoe.

You are required to give some suggestions to design a canoe which can travel faster and safer. Using knowledge of motion, forces and properties of materials, explain the suggestions based on the following aspects:

- The surface of the canoe- The shape of the canoe- The material of the canoe- The shape of peddle

AnswerSuggestions ReasonThe surface of canoe is smooth To reduce water resistanceAerodynamic shaped of canoe To reduce frictionThe canoe is low density So that the canoe is lighterThe peddle is big To increase the force Strong material of canoe and peddle So that it is not easily to break down

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59. Diagram shows an archer getting ready to shoot an arrow towards a target board from a far distance. When he releases the arrow, he observes that the arrow falls short of the target.

Suggest and explain how he would able to shoot the arrow to hit the centre of the target board, based on the following aspects:-the strength of the cord-the force constant of the bow-the material used for the bow-the design of the arrow-the way the arrow is aimed to the target

AnswerSuggestions ReasonsHigh strength of the cord So that it wont break easilyHigh force constant of the bow To store higher potential energyStrong and high strength of material So that it wont break easilyAerodynamic / streamlined arrow To reduce air resistanceAim slightly above the target The path is parabolic/curved/downward due to free fall motion

60. Diagram below shows four racing cars P, Q, R and S with different specifications. You are required to determine the most suitable car to complete in the Formula 1 Summer Race.

Car Shape Ridges on tyre Engine power Material for the car bodyP Aerodynamic Horizontal and vertical 518kW Light and elasticQ Aerodynamic None 745kW Heavy and stiffR Inverted aerofoil Horizontal and vertical 518kW Heavy and elasticS Inverted aerofoil None 745kW Light and stiff

Study the specifications of all racing cars from the following aspects:-The shape of car-Ridges on tyre-Engine power-Material for the car body-Explain your suitability of aspects. Justify your choice.

AnswerCharacteristics ExplanationInverted aerofoil shaped To create high pressure on top/ To create greater downward force/ To

increase stabilityNo ridges on tyre Less friction during motionHigh engine power To provide greater forward thrustLight and stiff material So that it does not break easily on impact

Car S is the most suitable because its shape is inverted aerofoil, no ridges on tyre, high engine power and light and stiff material.

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61. Table below shows the characteristics of airplanes wing design.Design Shape of cross section

of wingArea of wing Density of wing

material (kg/m)Difference between speed of air

above and below wing (m/s)W 38.0 2400 0.0

X 39.7 2300 21.8

Y 60.5 2000 20.5

Z 40.5 2050 15.5

You are required to choose the most suitable aeroplane wing and explain the suitability.

AnswerCharacteristics ExplanationAerofoil shaped of cross section of wing To produce the speed of airflow above the wings to be higher than

speed below the wingsLarge area of wing To increase lifting forceLow density of wing material Light/ To produce more upward resultant forceLarge difference of speed To increase the difference of pressureWing Y is the most suitable because it is aerofoil shaped, large, low density and the difference between speed of air above and below wing is big.

62. Table below shows five torchlights P, Q, R, S and T.

You are asked to choose and explain the most suitable torchlight.

AnswerCharacteristics ExplanationConcave reflector Reflected ray is convergingBulb located at principle focus So that reflected ray forms a parallel beam of lightBatteries connected in series To produce larger currentCopper connecting wire To produce low resistance/ large currentTorchlight Q is chosen because it uses concave reflector, its bulb is located at principle focus, battery connected in series and copper connecting wire.

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63. Diagram below shows an arrangement of lenses to construct an astronomical telescope using lens P and lens Q.

Arrangement of lenses

Focal length of objective lens, f /cm

Magnification of image

Distance between objective lens and eyepiece, D /cm

Diameter of objective lens, d

/cmJ 40.0 4.00 50.0 LargeK 40.0 0.25 60.0 SmallL 10.0 4.00 50.0 LargeM 10.0 0.25 60.0 Small

Explain suitability of the arrangement and each characteristic of the lenses and determine the arrangement which can produce the brightest and sharp image at normal adjustment.

AnswerCharacteristics ExplanationLonger focal length of objective lens To produce real, inverted and smaller imageHigh magnification of image To produce bigger imageDistance=fo + fe To produce image at normal adjustment/ To form image at infinityBigger diameter of objective lens More light can enter the objective lens/ to produce brighter imageJ is chosen because it has longer focal length, higher magnification of image, distance=fo + fe and bigger diameter of objective lens.

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64. Diagram 11.2 below shows a glass window which is opens outwards at an angle .

Diagram 11.3 shows the side view of the window. If rays of sunlight incident on the window undergo total internal reflection at points like X, direct sunlight would not be able to enter the room and it would be cooler. Four designs P, Q, R and S of the window are available and are designed such that it can be opened at a maximum angle of .

Design Glass /Refractive index Thickness /mm Thermal conductivity

P 1.5 3.0 Low 15Q 1.8 5.0 Low 10R 1.8 3.0 Medium 15S 1.5 5.0 Medium 10

Explain the suitability of each characteristic of the glass and the size of the angle and determine the most suitable design to be used so that the room can be kept cool during the day.

AnswerCharacteristics ExplanationHigh refractive index of glass So that total internal reflection easier to occur/ Smaller critical angleThick glass To keep cool/ To cut off more lightLow thermal conductivity To cut off more heat/ To reduce transmission of heatSmall angle Critical angle can be easily exceeded/ Total internal reflection easier to

occurQ is chosen because its high refractive index, thick and low thermal conductivity glass and has a small angle.

65.a) You are given two pieces identical prism with internal angle 45, 90 and 45 and two converging lenses to make a binocular. Using the material stated above, explain how you are going to build a simple binocular. b) Suggest modifications need to be done on the simple binocular to produce brighter and sharper image.

Answera) b)

66. Diagram 10.4 shows a restaurant in the town and always noisy. A student and his parents often visit the restaurant in Diagram 10.4 is not suitable for to the restaurant owner.

Using the appropriate physics concepts, the noise pollution. The modifications should include the (i) Materials used for floor, ceiling and wall.(ii) Finishing for table and countertops.(iii) Solution for large windows(iv) Dining space design

AnswerModificationsLoudspeakers are positioned at quite a distance away

The two main loudspeakers are not positioned opposite to each otherFix soft boards/ wooden materials which are sound absorbersUse thick carpet/ wooden floor/ rubber floorAssemble a high power speaker systemAssemble the speaker at high place

67. You have been assigned as a consultant to hall. Using the appropriate concept explain how the modifications that can improve audible (i) Distance between two stereo speakers.(ii) Wall and floor finishing(iii) Power of the loud speakers(iv) Positioning of speakers and microphones.

AnswerSuggestionsThe material of ceiling, floor and wall is soft, woodenSoundproof panels and floor tilesUsing ceiling clouds decorative suspended sound panels that floats from the ceilingTable covered with tableclothAreas with large windows, sound absorbing blinds

Divide into small area

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shows a restaurant in the town of Seremban. The restaurant is always packed witand his parents often visit the restaurant to enjoy a pleasant dinner. The

iagram 10.4 is not suitable for a quiet evening and they decided to suggest a few modifications

e appropriate physics concepts, suggest and explain the modifications that have to be doneodifications should include the following aspects:

(i) Materials used for floor, ceiling and wall.le and countertops.

ReasonsLoudspeakers are positioned at quite a distance away So that the distance between consecutive

constructive / destructive interference is smallerThe two main loudspeakers are not positioned To prevent multiple reflections

Fix soft boards/ wooden materials which are sound Reflection effects can be reduced

Use thick carpet/ wooden floor/ rubber floor To prevent echoAssemble a high power speaker system To produce a high amplitude of sound waves

Wide coverage/ The wave is not blocked

een assigned as a consultant to assemble a speaker system to improve the acoustopriate concept explain how the installation of the speaker system and the other

ations that can improve audible sound. In your explanation , elaborate on the following aspects:speakers.

Positioning of speakers and microphones.

ReasonsThe material of ceiling, floor and wall is soft, wooden To absorb excess sound

To reduce echoUsing ceiling clouds decorative suspended sound To absorb reflection of sound waves

To absorb echoAreas with large windows, sound absorbing blinds To capture sound and control reverberation from

windowsOpen area will produce echo

packed with customers restaurant to enjoy a pleasant dinner. The

a few modifications

have to be done to reduce

So that the distance between consecutive constructive / destructive interference is smaller

To produce a high amplitude of sound wavesWide coverage/ The wave is not blocked

acoustics of a school other

following aspects:

sound and control reverberation from

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68. You are asked to investigate the design and the characteristic of four transformers shown in Diagram 12.2.Explain the suitability of each characteristics of the transformer and determine the transformer which can be used as an ideal transformer. Give reasons for your choice.

AnswerCharacteristics ReasonsSoft iron core Easy to magnetized and demagnetizedLaminated core Less eddy current/ reduce energy lostThick wire To reduce resistance/ To increase currentCopper wire It is low resistance/ To reduce the loss of heatTransformer Q is chosen because of its laminated soft iron core and thick copper wire.

69. You are asked to investigate the design and the characteristics of four alternating current generators shown in Table 12.1. Explain the suitability of each characteristic of the alternating current generators and determine the alternating current generator which can supply a large direct current to an electrical component S shown in Diagram 12.2.

Characteristics ReasonLow density of material LighterHigh number of turns of coils Larger force acting on the coil/ Higher electromagnetic field strengthHigh strength magnets Larger force acting on the coilUse 4 diodes and a capacitor 4 diodes to provide full-wave rectification and capacitor act as a

smootherGenerator Y is chosen as it has low density of coil, high numbers of turns of coil, high strength magnets and it uses 4 diodes and a capacitor.

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70. Table 12 shows the characteristics of five substances P, Q, R, S and T.Substance Resistivity at 0C/ cm Melting point/ C Valence electron of the

doping substanceSize of the doping

atom compared with the size of atom

P 10 100 4 Very bigQ 10 600 3 Almost the sameR 10 800 4 BigS 10 120 2 Very smallT 10 300 2 Small

Explain the suitability of the characteristics of the substances to be used in the production of a semiconductor with better conductivity and determine the most suitable substance to be used. Give reasons for your choice.

AnswerCharacteristics ReasonThe resistivity at 0C is low A current can flow through it more easily/ Increasing the

conductivity of the substanceHigh melting point Not melting at high temperatureThe valency of the doping substance are 3 and 5 Valency of 3 is used to make p-type semiconductor and

valency of 5 is used to make n-type semiconductorSize of the doping substance is almost the same as the size of the substance

Can maintain the crystal-line structure of the substance/ Give good effect in the doping process

Q is chosen.

71. The door of the lift is fitted with a light transmitter and a detector which is a light dependent resistor (LDR). If the LDR detects light, the relay switch is activated and the lift door will close. You are asked to investigate the circuit of the lift, and design suitable circuit to close the door of the lift, if there is no people in front of the lift as shown in Table 12.

AnswerSuggestion ReasonLDR must connect to the base circuit If there is light (no people in front of the lift) no

current flow on base circuit, and no current flow on collector circuit and the motor wont switch on.

Relay switch must be connected to the collector circuit

If there is a small change in base current, transistor can amplify the current to the relay to switch on the motor.

Positive terminal of dry cell must be connected to collector of transistor and negative terminal of dry cell must be connected to emitter

So current can flow from collector of transistor to emitter

Resistance 10k must be connected in series to LDR To function as potential divider that applies a proportion of a total voltage across the emitter-base junction so that the junction is forward bias.

Resistance 1k must be connected in series to base of transistor

To limit the current passing through base of transistor

The most suitable circuit is P.