SPM 2010 paper 2

SPM 2010PAPER 2

(a) Based on Diagram 1.1, choose the correct path for one complete oscillation. Tick (x) the correct answer in the box provided.

Diagram 1.1 shows an oscillating pendulum.

1

x

(b) The stop watch in Diagram 1.2 shows the time taken for the pendulum to make 20 complete oscillations.

Based on Diagram 1.2, (i) statethe smallest division of the stop watch, ……………… s [1 mark] (ii) the time taken for 20 complete oscillations. ………… s [1 mark]

0.2

45.0

(c) What is the type of physical quantity for time? Tick (x) the correct answer in the box provided.

[1 mark]

x

Diagram 2.1 shows a loaded spring oscillating vertically in water. The oscillating system experiences damping.Diagram 2.2 shows the displacement time graph for the oscillating system.

(a) Underline the correct answer in the bracket to complete the sentence below.Damping is a situation when the (amplitude, wavelength) of the oscillation decreases.

[1 mark]

(b) State one reason why damping occurs in the oscillating system.

Water resistance / energy loss / friction

(c) Based on Diagram 2.2, (i) state the period of the oscillating system. ………… [1 mark] (ii) what is the frequency of the oscillating system? ……….... Hz [1 mark]

0.4 s

1/0.4 = 2.5

(d) What will happen to the period of the oscillating system when a heavier load is used? [1 mark]increase

Diagram 3 shows the activity-time graph of a radioisotope Potassium-42. This radioisotope emits beta particles and is used as a tracer to measure the quantity of salt in human body.

(a) State one characteristic of beta particles. ………………[1 mark]

Negatively charged

(b) Based on Diagram 3, determine the half-life of Potassium-42. Show on the graph how you determine the half-life of Potassium-42.

Half-life of Potassium-42: ……..hours [1 mark]12 hours

(c) Based on the half-life, state why Potassium-42 is suitable to be used as the trace. ……………………………………[1 mark]Short half-life so it is safe

Calculate the time taken for radioisotope Potassium-42 to reduce to 1/8 of its initial activity. [2 marks]

1 → ½ → ¼ → 1/8 3 x 12 hours = 36 hours

Diagram 4.1 shows a bright spot, P, formed on the screen of a cathode-ray oscilloscope, C.R.O., when it is switched on.

(a) What is the meaning of cathode-ray? ………………………………………

[1 mark]

(b) Explain how the bright spot is formed on the screen of the C.R.O. ………………………………………… …………………………………………

[2 marks]

High speed electron beam

Electron hit the screenThe kinetic energy changes to light energy

(c) Diagram 4.2 shows the bright spot is displaced to Q when a direct current, d.c. supply, is connected to the Y-input of the C.R.O. The Y-gain of the C.R.O

is set at 2 V/division. Calculate the input voltage of the d.c. supply. [2 marks]

2 x 2 V = 4 V

(d) Diagram 4.3 shows an alternating current, a.c. supply, is connected to the C.R.O. The Y-gain of the C.R.O remains at 2 V/division.Draw the output signal on the screen in Diagram 4.3 when the peak voltage of the a.c. supply is 6 V and the time base is switched off. [2 marks]

Diagram 5.1(a) shows a boy skating down a ramp from position X. Diagram 5.1(b) shows the velocity time graph of the boy from X to Z.

Diagram 5.2 (a) shows the same boy skating down from position Y by using another ramp.Diagram 5.2(b) shows the velocity time graph of the boy from Y to Z.

Both ramps are of the same slope and surface. (a) Name the physical quantity represented by the gradient of the velocity time graph. …………………………………………[1 mark]

acceleration

(b) Observe Diagram 5.1(a) and Diagram 5.2(a). (i) Compare the gravitational potential energy of the boy at X and Y. ………………………………….. [1 mark]The gravitational potential energy of the boy at X is higher

(ii) Compare the velocity of the boy at Z in these two situations. …………………………………… [1 mark]The velocity of the boy in Diagram 5.1 is higher

(iii) Compare the kinetic energy of the boy at Z in these two situations. …………………………………… [1 mark]The kinetic energy of the boy in Diagram 5.1 is higher

(c) Based on the answers in 5(b),(i) State the relationship between the gravitational potential energy and the kinetic energy of the boy. ………………………………….. [1 mark]

(ii) State the physics concept involved. …………………………………… [1 mark]

Gravitational potential energy is directly proportional to kinetic energy

Principle of conservation of energy

(d) (i) Based on Diagram 5.1(a), what happens to the velocity of the boy when he skates from Z to Q? ……………………………………… [1 mark] (ii) Give one reason for the answer in 5(d)(i). …………………………………… [1 mark]

Velocity decreases

Kinetic energy at Z > kinetic energy at QKinetic energy changes to gravitational energy

Diagram 6.1 and Diagram 6.2 show experiments on a sound wave.

(i) Compare the distance, X, between two consecutive loud sounds in these two situations. …………………… [1 mark]

Diagram 6.1 is greater than 6.2

(a) Observe Diagram 6.1 and Diagram 6.2.

(ii) Compare the distance, a, between the two loud speakers ………………… [1 mark]

Diagram 6.1 is shorter than 6.2

(ii) State the relationship between a and X.

………………… [1 mark]

a is inversely proportional to x.

(iv) State one other physical quantity that needs to be fixed to ensure the relationship in 6(a)(iii) is correct.

………………… [1 mark]

Distance between a and x // frequency // wavelength

Name the physics phenomenon involved. …………………………………… [1 mark]

(b) The frequency of the audio signal generator is increased.(i) What is the meaning of frequency? ……………………………………………………… [1 mark](ii) What happens to the distance between two consecutive loud sounds? ………………………………… [1 mark] (iii) Give one reasons for the answer in 6(b)(ii). …………………………………………………………… [1 mark]

Interference

Number of complete oscillations per second

Decreases

The wavelength decreases

Diagram 7.1 shows an object O placed in front of a concave mirror.

F is the focal length of the mirror and C is the centre of curvature.(a) What is the meaning of focal point? ....................................................... [1 mark]A point where all parallel rays converge after being reflected.

(b) Draw a ray diagram on Diagram 7.1 to show how the image is formed.

[3 marks]

Image

1. A ray from object parallel to its principal axis, reflects to F

2. A ray passing through C, will reflect at the same path, C

3.Extrapolation of both rays to form image

Diagram 7.2 shows the cross-section of a concave reflector used in a torchlight.

(c) Ray S from the filament bulb is incident at point Q on the concave reflector.(i) Complete the path of ray S on Diagram 7.2. [2 marks] (ii) State the light

phenomenon involved in 7(c)(i). [1 mark]Reflection

(d) The torchlight in Diagram 7.2 does not produce bright parallel rays. Suggest a modification that can be made to produce bright parallel rays through these aspects: (i) The position of the bulb ....................................................[1 mark](ii)The curvature of the reflector. ...................................................[1 mark](e) Suggest one other method to produce brighter rays by the torchlight shown in Diagram 7.2. ...................................................[1 mark]

Place the bulb at the focal point, F

Increase the curvature

Increase more voltage / mirror as reflector

Table 8 shows two types of pot and their characteristics.

(a) What is the meaning of specific heat capacity? …………………………………… [1 mark]The amount of heat absorbed to raise the temperature of one kg of material by 1 ⁰C

(b)Based on Table 8, state suitable characteristics of the pot if it is to be used for cooking something rapidly. Give reason for the suitability of the characteristics.(i) Material for making the pot.

[2 marks]Material for making the handle of the pot.

[2 marks] Mass of the pot.

[2 marks]

Copper / lower specific heat capacity.Heat up faster / good conductor

Polymer / high specific heat capacityHeat up slower / good insulator

Lower mass.Easy to lift and carry.

The pots are heated by using an electric hot plate of power 800 W. Based on the information in Table 8, calculate the time taken to achieve a temperature rise of 90 C for:⁰

(i) The clay pot [2 marks]

(ii) The copper pot [2 marks]

Pt = mcθt = [3.5 x 900 x 90]/ 800 = 354.4 sec

Pt = mcθt = [2.5 x 390 x 90]/ 800 = 109.7 sec

Determine the most suitable pot that is the safest to handle and can be heated in the shortest period of time. ………………………………………..

[1 mark]Copper pot

Diagram 9.1 shows a boy and his father sitting on two identical beach balls, A and B, respectively.

Their weights are balanced by the buoyant force.

What is the meaning of weight?[1 mark]

Force exerted on every object due to gravity

(i) Using Diagram 9.1, compare the weight of the boy and his father, the volume of the water displaced and the buoyant force acted on both of them.

[3 marks]• The weight of the father is higher• The volume of water displaced by ball B is bigger.•The buoyant force acted on the father is bigger

State the relationship between the buoyant force and:The volume of water displaced

The weight of water displaced

[2 marks]

As the volume of water displaced increases, the buoyant force increases

Buoyant force = weight of water displaced

Name the physics principle involved.[1 mark]Archimedes principle

(c) Diagram 9.2 shows what happens when a wooden block is held above the water surface and then released into the water.

When the wooden block is released, it falls into the water and goes completely under the water surface. Then it moves upwards and floats on the water surface. Using the concept of buoyant force, explain why the wooden block moves upwards and then floats on the water surface. [3 marks]

1st : Buoyant increases when the volume of the immersed wooden block increases.2nd : buoyant force is larger than the weight when the wooden block is moving upwards.3rd : Buoyant force equals to weight of the wooden block when it is floating on the surface of water.

(d) The State Forestry Department is going to organize a raft competition. As a team leader, you are required to give some suggestions to design a raft which can accommodate 15 participants and be able to move quickly in water.

Using your knowledge of motion, forces and properties of materials, state and explain the suggestions, based on the following aspects:The shape of the raft [2 marks]The material used for the raft [2 marks]The size of the raft [2 marks]The design of the raft. [4 marks]

Modification ReasonStreamline shape Reduce water

resistanceLow density material Can float easilyBigger size Can accommodate

more participantsA few layers of Displaced more

water / higher buoyant force

Attach plastic bottle, drum/ polisterene

To increases buoyant force

Attach sail / paddle/ fan / motor

Increase speed

Diagram 10.1 shows the red fringes formed in a Young’s double slit experiment.

Diagram 10.2 shows the green fringes formed when the red light of wavelength 7.0 x 10-7 m is replaced by the green light of wavelength 5.0 x 10-7 m.

(a)(i) What is the meaning of a wavelength? [1 mark]

Wavelength is the distance between two successive crest / trough

Based on Diagram 10.1 and Diagram 10.2, compare the wavelength of the light source used, the distance between two consecutive fringes, formed by the respective light and the distance between two consecutive fringes of red light and green light..Relate the wavelength of the light with the distance between two consecutive fringes.Name the wave phenomenon involved.[5 marks]

1st : wavelength of red is larger2nd : distance is equally space in red fringe or green fringes3rd : Distance between two successive fringe of red is greater than green.4th : The fringes separation increases with the wavelength5th : Interference

Diagram 10.3 shows a train in a tunnel. The sound waves from the train can be heard loudly and clearly at night.Diagram 10.3

The distance of the sound waves are further apart at the top than at ground level. Explain why this situation occurs, and state how this leas to the sound being loud and clear. [4 marks]

1st : At night, the ground cools quickly2nd : Air layer near the ground becomes colder than the layer above.3rd : Sound travels faster in warm air4th : Sound waves bend towards the observer / refraction occurs.

Diagram 10.4 shows the design of a dish made by a student to boil water in a kettle using solar energy.

Your are required to modify the design in Diagram 10.4 so that the water boils in a shorter time. State and explain the modifications based on the following aspects:

Shape of the dishThe type of surface of the dish/Size of the dishPosition of the kettle.The orientation of the dish.

Modification ReasonParabolic reflector Heat will be focusedShining / smooth surface

Reflection will be effective

Larger diameter More heat will be collected

Placed at the focal point

Heat converge to kettle

Facing the sun Can collect/capture more solar energy

Diagram 11.1 shows a boy of mass 40 kg sliding in two identical flumes, one after another.

Diagram 11.1 (a) shows the boy sliding down the flume, which is inclined at 30.0˚ to the horizontal. Diagram 11.1(b) shows the boy stationary in the flume when the flume is inclined at 17.5˚ to the horizontal. The frictional force acting on the boy in both flumes is 120 N.

What is the meaning of frictional force?[1 mark]

Force that oppose motion

(b)Based on Diagram 11.1(a), calculate:(i)The component of the weight parallel to the slope of the flume, WC. [2 marks](ii) The resultant force acting on the boy.

[1 mark](iii) The acceleration of the boy. [2 marks]

(i) 400 sin 30⁰ = 200 N

(ii) 200 – 120 = 80 N (iii) F = ma a = 80 / 40 = 2 ms-2

Using the concept of force, explain why the boy slides down the flume when the angle of inclination is 30.0˚ and remains stationary when the angle of inclination is 17.5˚. [4 marks]

1st : Wc > frictional force2nd : unbalanced force orResultant force acting3rd : Wc = frictional force4th : Resultant force is zero force in equilibrium

Diagram 11.2 shows four lawnmowers, J, K, L and M with different specifications. You are required to determine the most suitable lawnmower to cut grass effectively.Lawnmower J Lawnmower K

Lawnmower L

Lawn-mower M

Study the specifications of the four lawnmowers based on the following aspects:

Method of moving the lawnmower.Mass of the lawnmowerSize of the cutter blade.The angle between the handle and the horizontal line.

Explain the suitability of each aspect and then determine the most suitable lawnmower.[10 marks]

Characteristics ReasonPush Bigger forceLarge mass Down force bigger /

More stableSize of cutter is large

Cut more grass/ efficient / faster

Angle between handle is large

Force exert to ground bigger

Choose M because pushing, large mass, size of cutter is large and angle between handle is large.

Diagram 12.1 shows a candle flame placed between two metal plates, P and Q.

The metal plates are connected to an Extra High Tension, E.H.T., supply which produces a strong electric field between P and Q when the switch is on.(a)(i) What is the meaning of electric field? [1 mark]

A region where electric charges experience forces

What happens to the candle flame when the switch is on? Explain your answer.

[4 marks]

1st : The candle flame spreads out in two opposite directionsthe spread towards the negative plate is wider2nd : Heat ionize ion3rd : +ve charge attracted to –ve plate4th : +ve charge is heavier

(b) Diagram 12.2 shows four circuits, W, X, Y and Z, containing three dry cells of electromotive force, e.m.f., 1.5 V each, two bulbs, labelled 2 V, 0.5 W and resistor R.

You are required to determine the most suitable circuit that can be used to light up the bulbs with normal brightness. You may need to do some calculation. Study the specifications of all the four circuits based on the following aspects: The type of connection of the cells [2 marks]The connection of the terminals of the cells.

[2 marks]The connection between the resistor and the bulbs. [2 marks]The type of connection of the bulbs. [2 marks]Explain the suitability of each aspect and then determine the most suitable circuit. Give a reason for your choice. [2 marks]

Characteristics ReasonDry cell in series Increase voltage

To produce emf greater than 2 V

+ve terminal cell to –ve terminal next cell (+ve to –ve)

Current flow / bulb lights up

Characteristics ReasonConnection resistor and bulb in series

To ensure the voltage across the bulb does not exceed 2 VBulb does not blown upIncrease resistance. Total current is 0.5 A

I bulb = P/V = 0.5 / 2 = 0.25 AI total = 0.25 x 2 = 0.5 A

V bulb = 2 VVR = (0.5)(5) = 2.5 V

Characteristics ReasonConnection of bulb is parallel

To produce voltage across each bulb is 2 VReduce resistanceIncrease currentIf one bulb blow another bulb still functionV bulb = 2 V, VR = 2.5 VIbulb = 0.25 AI total = 0.5 A

I bulb = P/V = 0.5 / 2 = 0.25 AI total = 0.25 x 2 = 0.5 A

V bulb = 2 V VR = (0.5)(5) = 2.5 V

Characteristics ReasonChoose X because the cells are connected in series, -ve terminal of cell is connected to the +ve terminal of the next cell, resistor is connected in series with bulb and bulbs are connected in parallel

Diagram 12.3 shows an electric circuit.The e.m.f. of the cell is 2.0 V and its internal resistance is 1.0 Ω. Calculate the reading of the ammeter when(i) Only switch S1 is on, [2 marks](ii) Both switches, S1 and S2 are on. [3 marks]

(i) 2 = I (1 + 5) I = 0.33 A

(ii) 1/R = 1/5 + 1/12 R = 60/17 = 3.53 Ω 2 = I (1 + 3.53) I = 2 /4.53 = 0.4415 A

Why doesn’t the book slide down?

W

f

R

θ

The forces acting on the book are

balanced.

W is resolved into 2 components

Wx along the plane

Wy

perpendicular to the plane

Wx = f Wy = R

Resultant force = 0

θWX

Wx = W sin θ

WY = W cos θ

Resultant force = WX – 150

Figure below shows a worker cutting grass by pushing and pulling a lawn mower.

Q 1

Using Physics concepts, compare the difficulty of the job when the worker : (i) pushes the lawn mower. (ii) pulls the lawn mower. You may use diagrams in your answer.

(i) pushes the lawn mower.

FFY

FXWeight of lawn mower, W

FYTotal downward force: = W + FY

Downward force is greater, so the lawn mover feels heavier

(i) Pull the lawn mower.

FFY

FXWeight of lawn mower, W

FY

Total downward force: = W - FY

Downward force is lower, so the lawn mover feels lighter.