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Physics Modification tingkatan 4
Practical Physics (Universiti Malaya)
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MODIFICATION-SECTION B
Soalan ini berada di dalam Section B. Cadangan dan alasan dalam soalan ini juga boleh digunakan di dalam Soalan
Section C – Making Decision. Dengan contoh yang diberikan ini akan berupaya meningkatkan kemahiran berfikir
pelajar di dalam membuat modifikasi dan membuat keputusan bagi situasi yang diberikan di dalam soalan
peperiksaan.Insyaallah.
CHAPTER 1
1.
Suitable ruler to use in laboeratory
Suggestion
Smallest size scale 0.1 cm
High accuracy
High consistency
Plastic material
Thin thickness
Explanation
More accurate
Less error in measurement
Low relative deviations
Avoid parallax error
Avoid parallax error
CHAPTER 2
2.
Explain the suitability feature of arm exercise equipment.
Suggestion
Spring made of steel
Two // more spring arrange in parallel
Spring with ticker wire
Smaller diameter coil of spring
Choose large force constant spring
3.
Suggest the suitable cloth , equipment and techniques to improve high jumper athlete and their safety .
suggestion
Use tight and light suit
Use spikes shoes
Use thicker mattress
The athlete have to sprint before jump
Athlete have to bend the body during fall
4.
Explanation
Less air fraction
Better grip support while running and prevent slippery
Increase time impact , reduce impulsive force . prevent back
injury
Can increase kinetic energy
Increase the time impact , reduce impulsive force
Explain the characteristic of spring to make baby’s cradle.
Suggestion
Choose large force constant spring
Choose large diameter of wire
Large diameter coil of spring
The spring is made of steel or alloy
The arrangement of spring is two or more line in
parallel
5.
Explanation
Can withstand higher force
The spring system is stiffer
Wire will not easily break
The smaller the diameter coil less elastic the spring, so the arm
exercise would not so hard
Will make strong spring, the spring will stiffer and not broken
easily
Explanation
Will make strong spring, the spring will stiffer and not broken
easily.
The larger diameter the stiffer the spring is.
The larger the diameter coil more elastic the spring is
Steel and alloy is stiffer than iron
The spring is stiffer
Explain the most suitable design of spring for shock absorber for motorcycles.
Suggestion
Small diameter of spring coil
Choose large diameter of wire
Force constant is more than 1000N
Higher spring constant
Small natural frequency
Explanation
Enough space for the spring
The larger the diameter the stiffer the spring
Can support motorcyclist and passenger up to 100kg
Small compression of the spring
To reduce bumping, comfortable for user
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6.
Explain the simple characteristic of the rocket than can travel with greater acceleration.
Suggestions
Choose metal with high strength and hardness
Frame of rocket is made of low density metal
Multistage rocket invented
Rocket need to carry a tank of oxygen
Silver color rocket
Cover the body of rocket with heat insulator
Aerodynamic shape
7.
Suggest and explain the build of water bottle rocket in school competition to move higher altitude and has
longer time on the air.
Suggestions
The body of rocket must be tough
Smaller mass
The shape is streamline/aerodynamic
Nose cone or bullet shape on top of body
45 angle of launching
The volume of water is half or 1/3 from the
whole volume
Attach 3 or 4 fins at the tail of rocket space
equally
Attach parachute
8.
Explanations
Do not break easily in high pressure and when landing
Rocket will accelerate faster
Reduce air resistance
To improve the aerodynamic of rocket
The rocket can travel maximum distance
To increase momentum and impulsive force
Rocket will move smooth and stable
will make the rocket floating and has longer time on the air
before landing//decrease the speed of falling due to air
resistance
Give suggestion to improve the design of jet engine so that it can be use for larger airplane at the higher speed.
Suggestions
Increase more fuel injectors
Increase the size of the combustion chamber
Decrease the diameter of the nozzle
Increase the speed of blade/use bigger blade
Blade and engine made of strong materials
9.
Explanations
Even under pressure the shape will not change easily
Lighter, can increase acceleration
Each stage has burning fuel, pump and combustion chamber. It
will slip off when fuel of each chamber completely burn. When
the mass decreases, the acceleration increase
To enable the combustion of fuel in space
Reflect light efficiently so the temperature of the rocket will
not rise
Friction between air and body will increase heat. The insulator
will reduce heat conductivity
Reduce air friction, move faster
Explanations
More fuel to be burnt to produce greater force
More space for fuel to burnt
Exhaust gas ejected at higher velocity
Increase the air intake
Can withstand strong pressure and won’t break easily
Base on the physic principle, suggest the design of roller skate track so it can be use to oscillate skate
continuously.
Suggestions
Semi circular curve shape
Smooth surface
The slope slightly increase and decrease
Use strong material such concrete of foundation
of the track
Soft layer at the surface
Explanations
Exchange between kinetic energy and gravitational potential
easily
Reduce frictional force/easy to slide
Easy to oscillates cause by changing of energy
Withstand high impact such as high force of jumping and
landing
Reduce impulsive force when landing, low risk if accident
10. Explain the most suitable design of motorcycle that can move fast, safe and save time in racing.
Suggestions
Lower seat height
Bigger width of tire
Less thread pattern
Smaller mass
With ABS
Explanations
Lower center of gravity or more stable or safer to turn.
Bigger surface area, better support or low pressure acts on the
tires or more friction when breaks.
To decrease friction of tires to the road, can move fast
Lighter, can move faster or low inertia
Motorcycle does not stop immediately or can be controlled if
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direction changes or does not move sideways or more friction
with ABS
11. Suggest and explain how to make suitable beach motorcycle which able to move on the sand smoothly and
comfortable.
Suggestions
Deep thread pattern // more definitive pattern
Large tire (big surface contact with ground)
Soft seat and water resistance
Excellent resistance to rusting
Attach shock absorber with higher spring
constant and small natural frequency.
Low density body
Explanations
Better grip on sand, able to move smoothly on sand
Reduce total pressure of car, increase stability and the car
would not get stuck in the sand
Comfortable for cycles and would not get wet easily
Everlasting. Would not rust easily
Reduce bumping, comfortable to cycle with
Lighter, would not stuck in sand
12. Suggest the suitable cloth and the best techniques to catch ball to prevent injury for goalkeeper.
Suggestion
Wear glove
Use soft material for glove
Wear cloth which is made from material with
moderate specific heat capacity
Base of shoes has stud
When catching the ball, the goal keeper should
move his hand backwards
The ball should have enough air pressure inside
Explanations
Reduce painful of the player’s hands when touching the ball
with big impulsive force.
Lengthen the time impact, reduce impulsive force.
The cloth can absorb more heat when the player is sweating to
maintain the temperature of player.
Player give great pressure to make stud sink into ground and
give stronger support without slipping.
This action lengthen the time impact between ball and hand, so
it reduce the impulsive force.
Shorter the time impact between foot and ball, so impulsive
force increase then the ball will has high speed and travel far
away.
13. Using physics concept, suggest and explain suitable athlete’s attires, running, jumping, landing techniques and
other aspects to help the long jumper can jump further.
Suggestion
Use tight and light suit
Use spike shoes
The athlete have to sprint before jump
The athlete have to push the body infront while
jumping
Athlete have to bent the body during fall
Explanation
Less air friction
Better grip support while running and prevent slippery
Can increase the kinetic energy//momentum
Increase the elastic potential energy//able to increase longer
distance of jumping
Increase the time impact, reduce impulsive force, less injured
14. Safety feature in car
Characteristic
The bumper of car is prone to crash
The sitting space of the passenger is reinforced
Use safety belt
Use air bag
Antilock breaking system(ABS)
Strong steel struts
Tire with tread
Explanation
It will increase the time impact, the impulsive force will reduce
To protect the passenger
During collision, safety belt will hold the passengers from
thrown infront due to inertia
Will inflate when accident occurs, the driver safe from hitting
steering
Allow car to stop quickly on slippery road and prevent from
skidding
Give good protection from side on collision
Can stays contact with road, prever slippery
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15. Explain the suitable loaded lorry which can carry liquid, such as petrol
Suggestion
The load of lorry should be divided into many
smaller tank
The load must be tied
Far gap distances between tractor and trailer
Use more tire for lorry
Small belt behind lorry
Use antilock break system (ABS)
Explanation
To reduce effect of inertia
So it will no fall of from the lorry
Prevent collision between tractor and trailer, easier when
turning
Pressure will be separate to all tires, able to carry more loads.
Lower pressure better support and stability
To discharge spark, safety reason to prevent from burning the
petrol
The lorry can stop easily without skidding
16. Explain the design of and how kayak which can travel faster and safer.
Suggestion
Streamline /aerodynamic shape of body
Smooth surface body /coated with wax
Low density material
Strong material body and peddle
Wider peddle surface
Wear safety jacket
Explanation
Reduce water resistance
Reduce friction of body towards water
Lighter , easier to float, easy to carry and sail faster
Everlasting , not easily broken
Greater force because more water are peddled up
Passenger can float and safe if they fall into water.
17. Give suggestion to design a sail boat which can travel faster and smooth.
Suggestion
Streamline /aerodynamic shape of board
Smooth surface board/coated with wax
Low density material
Strong material
Wider sail
Explanation
Reduce water and air resistance,can increase lifting
Reduce friction toward water
Lighter, easier to float and sail faster
Withstand strong wind, not easily damage
Greater lifting force because more wind are captured
18. Modified the ship that can carry more and heavier load, move faster and safe while travelling.
Suggestion
Strong material
Low density material
Has more than two stage,plimsoll line
Big size
Aerodynamic/streamline shape
Waterproof sail
Explanation
Can withstand great force
Light weight
Safe to travel on the fresh and salt water
Can place more goods
Reduce water friction.
Sail would not get e=wet easily.
19. Suggest how to increase the safety for motorbike racer to reduce injuries / accident
Suggestion
Use helmet
Use helmet with hard outer casing and soft inner
liner
Use safety jacket
Use gloves
Use padded leathers suit
Explanation
To protect the head
Helmet reduce head injuries in a crash by spreading the impact
with hard outer casing and absorb energy with soft inner linear
of styrofoam
To protect the from injuries , cut ,burn
To protect the hand
Will soften any impact and protect the skin from abrasion
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20. An earth-monitoring satellite falls into the earth’s atmosphere at a high velocity and reaches a high
temperature. This is caused by the earth’s gravitational force and air resistance.Using the appropriate physics
concepts, suggest and explain suitable designs or ways to protect the satellite and its equipment:
Suggestion
Aerodynamic shape
Heat shield / material that is hard to burn
High melting point //ceramic
Landing in water // air bag
Light material / / small mass // low density
Paracute / /Retro rocket
Hard material // stiff composite
Explanation
To reduce air resistance
To protect the capsule
Do not melt
Increase time of impact// Reduce impulsive force
-Reduce the inertia // -reduce the momentum //
-reduce impuls
To reduce speed
Not easy to bend
21. Explain how you would design the pile driving system.[the ram hammer is lifted to a height by the crane and
allowed to fall on the pile.
Modification
Large hammer weight
Ram hammer made from hard material such as
alloys
Hammer raised at higher position
Stronger End of the top of the concrete pile
Sharp End of the bottom of the concrete pile
Reason
Large momentum when it hit the pile
Not break easily/last longer
Inrease the gravitational potential energy
To avoid break at the top couse by the hammer
To increase the pressure
CHAPTER 3
22. Efficient brake system
Suggestions
Type of liquid: oil
Thickness of brake line :high
The ratio of cross sectional area for wheel piston
and master piston :high
The chosen of type of brake for front rear wheel:
Front wheel - disc
Rear wheel - drum
Explanations
Uncompressible
To counter the high pressure from the liquid
To produce larger force on wheel piston
Disc brake is more efficient than drum brake
23. Explain the design of hydrometer which can be use to determine a wide range of densities of liquid.
Suggestions
Small stem and long
Glass wall
Large diameter of bulb
Scale can be made bigger or smaller than the
density of water.[calibration]
- The hydrometer is floated in alcohol.
The liquid level at the stem is marked
(upper level)
- Then, the hydrometer is floated in
higher density liquid like mercury and
marked (lower level)
Lead shots
Explanations
Increase sensitivity where the scale division are far apart so
that small changes in density can be detected
Do not erode and small adhesive force
High up thrust / displaces more liquid / able to float easily
Ability to measure a wide range of densities of liquids.
Hydrometer can stay upright
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24. Describe the suitable design to build mobile tent for Sure Heboh event which will be construct at open space
for a week. Using appropriate physics concept, suggests and explain.
Suggestion
Choose low density metal for frame
Use hollow rod which can assemble easily
Water proof canvas
Anti rust rod
Sharp end rod
Explanation
Light weight and strong
Hollow rod is not heavy, but equally strong, easy to mobile
anywhere, faster to build, can reduce the cost of
construction and transport
If raining, would not getting wet
Can withstand rain and long lasting
Small surface area, so higher pressure to ground, yet the
tent can be planted into ground firmly and stand still
25. Explain the necessary modification for the structure of dentist chair for children that are suitable and save for
the adult.
Suggestion
Increase the cross-sectional area of big piston and
decrease the cross-sectional area of small piston
The wall of pipe is made up of strong alloy to hold
the fluid
Change the less control into electric touch control
The surface area of the seat enlarged
Use non-corrosive oil in jack
Explanation
To increase the output force acting on big piston / to lift
havier adult / to increase force multiplier of system
To withstand the strong pressure that might cause cracking
in the channel
To lift or lowered the chair to the desire weight more easily
and safety
To support the people with the large bodies
So that the wall of the pipe will not be controlled and cause
leakage
26. Explain the build and design of hot air ballon wich can fly higher altitude faster and suggest some safety aspect.
Suggestion
Large ballon
Many hot air burner
Synthetic nylon ballon
Gas temperature is high
Total of mass is low
Rattan basket
Fly on early morning or late afternoon
Explanation
Produce bigger buoyant / upthrust force, increase the
volume of air displacement
Heat up the gas inside faster
Air proof, light weight and strong material
Reduce the density of air in ballon
Ballon move upward faster
Longer the time impact, reduce the impulsive force to
passanger when landing
The temperature outside the ballon is cooler compare to
the inside of ballon, so the ballon will rise higher
27. Explain the basic structure of small submarine that can be use for underwater exploration.
Suggestion
Strong material
Aerodynamic shape
Thick wall
High density materials
Ballast tank
Sonar transmitter and receiver
Explanation
Does not break easily
Reduce water resistance
Water pressure increase with depth
Increase mass / can submerge easily
To increase or reduce weight
To estimate and depth
28. Suggest the design of submarine which can submerge and float in the sea.
Suggestion
Ballast tank are partially filled with water
Aerodynamic // streamline body
Use hard and stiff materials for body
Attach periscope
Use nuclear power sources to generate power
Explanation
The submarine will partially float
To reduce water resistance
To overcome the pressure of water in the sea
To view surrounding area when submarine float
Cheap and lasting power
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29. Explain the characteristic of material to be use for making the sole of jungle trekking shoes.
Suggestion
Rubber sole
Low density
Many stud
Low expansion effect
Excellent ability of stretch
Explanation
Good impact absorber
Light weight
Give extra grip
Not loose easily
Comfortable to feet, foot can move unstressed
30. Using physics concept, explain necessary deep sea diving suit and other accessory to carry.
Suggestion
Choose strong helmet with thick metal and glass to
cover head
Use thick glass in front of diver face
Explanation
To withstand high pressure of water and protect the head
Use water proof suit and able to withstand pressure
Due to depth, the pressure under water is very high
Bring along gas containing mixture of oxygen
To provide oxygen to diver for breath
Use very heavy suit
The diver enable to stand on the floor of ocean and able to
fight buoyancy of water
Enable the diver to see surrounding and at the same time
able to withstand the pressureof water
31. Modified the passanger airplane to cargo airplane that needs to carry more laod, less use of fuel, effenciency
and safety to travel.
Suggestion
Increase the size of the body
Increase the length of the wing
Increase the thickness of the body
Use a more powerful engine
Increase the number of tyres
Protective bar between the cabin and the pilot
Pilot has ejected seat during emergency
Explanation
To increase the space
To increase the upthrust
To stand higher pressure difference
To overcome bigger inertia and do more work per unit time
To support higher mass or pressure while landing
To prevent moving object to knock at the pilot while
landing
To save the pilot if plane crash happened
32. Design Vacuum Cleaner
Suggestion
Large fan driven
Powerfull of lectric motor
Narrower inlet opening
Using a very large filter to block dust particles while
allowing air moleculs to pass through
Larger spaced for depositing and collecting the dust
particles
Explanation
Inrease the spped and amaunt of airflows
Inrease the spped and amaunt of airflows
Inrease the velocity/decrease air pressure
To have a lots of surface area and many pores for air to
flow through
Ensure that the air flows through the filter is not block by
too many dust particles
33. Design paint sprayer
Suggestion
Large size of air vessel
Rubber material for the vessel
Narrow shape of the tube
Fibre glass material for the rod
Size of nozzle is narrow at the end
Explanation
Compress more air/can exert large pressure
More elastic/easier to squeeze
Air can move with high speed
Stronger and last longer
The paint can be sprayed evenly
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34. Design hidraulic jack
Suggestion
Bigger crossectional area of slave piston(big piston)
Small crossectional area of master piston(small piston)
Longer handle
Low density of a body
Oil for liquid
Release valve between small and main reservoir(reset)
Explanation
Produced higher force
Less forced is needed/produced bigger pressurre
Less forced is needed to press small piston(master
piston)
Lighter
Non-compressable
Liquid can flows into small reservoir easily when push
the reset button.
35. Design hydrometer
Suggestion
Bulb with lead shot at the lower section
Cylinder with bigger diameter at the bottom
Cylinder with smaller diameter at the upper section
Smaller scale
Filled with air
Glass wall
Explanation
To submerge the hydrometer and not overturn
not overturn/increase stability
A small reading scale can be incorporated/inrease the
sensitivity
inrease the sensitivity
Inrease the beyoncy force
Not corrode easily
CHAPTER 4
36. Most suitable design of thermometer to use in Antarctica
Suggestion
Use alcohol as liquid – in glass thermometer
Use thin wall of bulb
Use small diameter of capillary tube
Use thick glass wall
Use round glass stem
Explanation
Freezing point of alcohol is -115oC .So , it will not freeze
at low temperature
So it will sensitive to the change of heat
Alcohol can expand at high rate for the small change in
temperature
The loss of heat to surrounding is small
Can act as magnifying glass , so the alcohol level can be
seen clearer
37. Most suitable design of clinical thermometer
Suggestion
Use mercury
The scale range from 35oC to 42oC
Small diameter of capillary tube// extra fine bore
tube
Use thin glass wall of bulb
Use round glass stem and wall
Explanation
Easy to read because it colour and opaque
To measure human body heat
Mercury can expand at high rate for a small change in
temperature
Sensitive to change of temperature
Can act as ,magnifying glass. So, mercury can be seen
clearly
38. Explain the design and the characteristics of the cooking pan
Suggestion
Base is made of a copper
High density of base
Body is made of aluminium
Handle is made of wood or plastic
Choose low density material for handle
Transparent pot cover
Explanation
Copper has a lower heat capacity it become hot very quickly
Heavier base make the pot stable and not topple over easily
Low specific heat capacity becomes hot very quickly but it
low density make it overall weight of weight lighter
High specific heat capacity so the handle do not become hot .
Safe
Does not add much to the total weight of pot
Able to cooker to see the food. Food cover will trap the heat
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39. Suggest and explian the design of water heater to boil a large quantity of water faster ,efficient and safely
Suggestion
Explanation
High melting point,high heat energy
Longer wire,increase the resistance
Not easy to melt at high temperature
Does not get rust easily
When temperatures reach 100 Celsius, the water heater
will automatically turn off
Use tungsten
Coiled
High melting point
Lower rate of rusting
Use thermostat
40. Determine the modification to be made for container,so the cut fruit will keep cool, remain fresh and easily
seen by customers.
Suggestion
Use container with high specific heat capacity
Place small ice packet below the bottom of the cut
friuts
Add salt to the packet of ice
White wall colour of container
The container has double wall
Transparent wall of container in front of customer
Explanation
Able to slow down the loss of heat from the container
The cut fruits is chill and juicy, ice able to absorb a large
amount of latent heat when melt
Foreign matter will increase the freezing point of ice, so
this will slow down the ice from melting
Can avoid absorbtion of heat from the surrounding
Avoid heat from surrounding transferred easily to
container. The inside container remains cool
The customer can see and choose the cut fruits easily
41. Investigate the most suitable liquid that can be use as coolant for car engine using physics concept.
Suggestion
Low freezing point liquid
High boiling point liquid
High specific heat capacity liquid
Explanation
Will not freeze easily during winter weather
Do not easily boil when absorbing heat from the engine
Can transfer large contain of heat with a small rise in
temperature. Able to cool up the engine
The metal part of the engine will not corrode easily
Low ability to react with metal
42. Most suitable thermometer for laboratory to measure the temperature of ice and boiling point of water
Suggestion
Size of the bulb is small
Use thin wall of bulb
Use mercury
Use thin wall capillary
Has minimum size scale with small division
Explanation
Does not need a lot of heat to heat up the mercury to
expand
So it is sensitive to change of heat
Freeezing point of the mercury is -39 degree celsius and
boling point 357 degree celsius . Able to has a range from 10 to 110 degree Celsius. Mercury can expand a high rate
for small change of temperature
Able quick heat transfer from the surrounding to the
mercury. So, the thermemeter is more sensitive
Making thermometer a sensitive instrument
43. Modified and explain the design of an efficient solar water-heating system on the roof.
Suggestion
Pipe embedded in plate must be long
Use metal pipe as pipe inside the plate
Use insulator behind the absorber panel
Use black absorber panel
Cover the top of the panel with glass
Put the tank at higher level
Explanation
Longer pipe will has greater surface area which can
absorb heat faster
Metal is good heat conductor , so heat will easily
transmit to water
Insulator will prevent the heat loss
Black is good heat absorber
Heat will trap inside due to green house effect
To give higher pressure
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44. Explain the build of solar cooker oven that been use in science month competition at your school to boil 500ml
water in short time.
Suggestion
Build the solar cooker with shiny// silver colour
reflector inside
Use metal cooker
Paint the outside part of the solar cooker and the
cooker ( contain water ) with black colour
Wrap the cooker with plastic or glass
To trap heat, the temperataure will increase
Explanation
The light will reflect to the cooker and heat up the water
Good conductor
To absorb
Avoid heat from release to sorrounding
To absorb heat, the water boil faster
45. Suggest the design of heating system in the house and characteristics of heating agent. The house use central
heating system with boiler, radiator and pipelines.
Suggestion
Use strong material
Use metal pipe with good heat conductor
Increase length of cooling coil
Use greater boiling point liquid
Low rate of rusting material
The bigger size of radiator fan
Pipe in coil structure is used
Explanation
Not easily break
Increase the rate of heat transfer
Can transfer the heat faster to surrounding
Liquid not easily change into vapour
Long lasting, not easily rust
Can blow and cool down larger area
Increase the time of floe and increase the quantity of haet
transferred.
46. Suggest the characteristic of material to build food container which can keep the food warm.
Suggestion
Food container should made of low density
material
Melting point of container should be high
Specific heat capacity should be high
Thermal conductivity is low.i
Double wall
Explanation
Lighter , the container able to be move from one place
to another.
To prevent the container from melting up when hot
food is store inside
So the container will not get hot easily. Safe to touch
and handle.
Good heat insulator , to ensure the heat not loss and
the food remain hot.
To prevent hest loss.
47. Explain the characteristic and design of thermos flasks to maintain hot water.
Suggestion
Use hollow plastic stopper
Vacuum space
Has double wall
Double walled tube coated with shiny paint
Double walled made of glass
Explanation
Able to trap air as air is poor heat conductor.so,less heat
loss through stopper.
Prevent heat loss through conduction or convection
Has vacuum in between heat not easier pass through the
wall of thermos.
Shiny surface reflect heat from the wall of thermos flasks
back to water.so the water remain hot.
Glass is bad conductor.it will reduce heat loss.
48. Explain how the design of radiator of the car and characteristic of cooling agent which can absorb heat at short
time,
Suggestion
Increase the length/area of cooling coil
Increase the number of fin blades
Use larger fan
Use cooling agent liquid with greater boiling point
Use cooling agent liquid with higher specific heat
capacity
Explanation
Can transfer the heat faster to the surrounding
Can cool down faster
Can cool down larger area
It won’t boild easily in high temperature
Able to absorb large amount of heat
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CHAPTER 5
49. Determine and explain in the build of magnifying glass to be use for enlarging the image of stamp
Suggestion
Explanation
Choose convex lens
Excellent clarity of lens
Small focal length
Medium diameter of lens
The object is place less distance than focal length
The image will magnify
The image is clearer
Able to focus nearer
Able to be hold by hand to identify the stamps
The image form is magnify, virtual and upright
50. Explain the suitability of the mirror that be use in shop to watch over the customer
Suggestion
Use convex mirror
Greater reflectivity of material
Choose a bigger size of mirror
Place the mirror at the corner of shop ceiling
Low density
Explanation
Wider field of view
Clearer image
Enable wider view and sharper image
Easier to look at and won’t disturb the customer pathway
Lighter to hang up
51. Design fibre optic
Suggestion
Use refractive index of outer layer is less than the
refractive index of inner layer
Use high flexibility material
Use strong material
Use thin material
Low density material
Explanation
So that total internal reflection can happen in the fiber
optic.
so that it can be bend easily
do not break easily
Lighter // can be use in small area
Lighter
52. Determine and explain the build of microscope using lens P and Q with focal length of 15 cm and 5 cm
respectively. Suggest modification that need to be done to get brighter ang bigger image.
Suggestion
P as eye piece and Q as objective lens
Fo < u <2fo
Adjusted so that u < fe
Distance between lenses > fo + fe
Store in a cool and dry place
Use more powerful// shorter focal length lenses
Use a lamp near the object// use bigger diameter
of objective lens
Explaination
Focal length of P is longer than Q
To produce real, inverted and magnified image
To produce virtual. Inverted and bigger image// to acts as a
magnifying glass
To produce bigger image from the eyepiece // to increase
the magnification
To avoid formation fungus at the lenses
To produce bigger image
To produce brighter image
53. Explain the suitable characteristic of the mirror to be use as outdoor safety mirror at the corner of the road
Suggestion
Explanation
Use convex mirror
Excellent weather resistance
Excellent impact resistance of material
Bigger size mirror
Greater reflectivity of material
Place at the sharp road corner , at bending road
Small roof
Wider field of view
Able to withstand bad weather
Save cost, everlasting
To enable a wider view and sharper image
Clearer image even in bad weather
To minimize from accident occur, to enable motorist see
the oncoming traffic
Protect from rain drop for better image
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54. Detemine and explain the build of Astro disc using appropriate physics concepts.
Suggestion
Choose convex curve parabolic
All signal are focus on focal point
Smooth surface of disc
Locate the disc at high and facing towards satellite
Clean surface of disc, no water drop or dirt
Explanation
The signals come can be focus at one point
Better reception
Better reflection
No obstacle, better signal
Better reflection, almost 100% reception receive by feed
horn
55. Modified the slide projector that need to be place in school hall and can be seen by many student with clearer
image.
suggestion
Use higher power bulb
The filament of the bulb is at the focus point of the
concave mirror
More curvature
Lens between f and 2f
Increase the distance or further away the screen
Electric fan operates during and after the lamp is
switches on
Use condenser mirror
Use a concave mirror instead of plane mirror
Place the filament at centre of curvature of the
converging mirror // use high powered lens
Use heat filter
Explaination
Higher intensity of light or more light produced
The light focuses at one point. // parallel ray can be
obtained after reflection by concave mirror
More light to be reflected (upward) // less light toward
other direction other than upward
To produce real ang enlarge or bigger images
Larger image produced
Cooling system to stabilized the temperature (heat energy
produced by filament bulb) to increase the projector
lifetime
To concentrate more light to the slide
Focus the light directly to the lens // increase the
intensity og light
Light goes directly from the lamp and reflect back on the
same path // increase the intensity of light toward the
transparency // to get brighter image
To absorb excess heat to the transparency
56. Determine and explain the build of telescope using lens J and K with lens K is thicker than lens J which produce
bigger and clearer image.
Suggestion
 C hoose lens K as eyepiece lens
Lens K is thicker than lens J

Choose lens J as objective lens
Use bigger diameter lens as objective lens
Use low power convex lens as the objective lens
Use high power convex lens as the eye lens
Use bigger diameter of objective lens
Expalanation

Light ray is refracted more in lens K than lens J, focal
length of lens K is shorter than lens J
 Therefore the thickerthe lens, the greater the
refraction of light and with that the shorter the focal
length of a lens will be
Characteristics of objective lens for telescope is
 Has larger surface area which allow more light
enter
 Has a longer focal length
 Magnification of telescope =f0/fe
Low power lens has a longer focal length ,fo higher,
magnification higher
High power lens has a shorter focal length,fe higher,
magnnification higher
More light permitted to enter the telescope and a clearer
image is seen
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CHAPTER 6
57. Design a good beach
Suggestion
near the bay
High retaining walls
Wall from concrete
Concrete barrier structure with a gap
Tambak laut supaya lebih cetek
More number of tree
Uneven surface of retaining wall
Explanation
divergence of the waves energy /calmer
Over flow
To reflect the waves from the shore
Reduce direct impact of the waves on the shore
reduce erosion are built
Waves passing through the gap will be diffracted in the
children’s area.
-reduce amplitude
Reduce speed
Diffraction occur will reduce tha amplitude
Reduce energy
58. Suggest and explain how ordinary fishing boat can be upgrade to the new boat which complete equipment to
detect the crowd of fish.
Suggestion
Attach radar system to the ship
Explanation
This equipment needs to detect crowd of fish and for
measurement the depth of the crowd of fish
-Use to produce ultrasonic pulses
To detect ultrasonic pulses
-To measure the depth of fish by calculating d=vt/2;
d=depth, v=velocity, t=time
-Ultrasound not produce sound
-Ultrasonic wave has higher frequency, more energy, so it
can move further
The penetrating power is higher
a) Ultrasonic transmitter
a) Microfone reciever
b) CRO
Use ultrasonic wave
Use high energy wave
59. Explain the suitable design or method to build quality concert hall.
Suggestion
Cover the hard wall with soft board or thick curtain
Place the wall with hole or egg carton design
Fixed 2 loud speaker in concert hall
Arranged the sit at antinodal place
Use glass or mirror hall which is the type which are
not easily broken
Use special computer to generate sound wave which
produce destructive inteference
Explanation
Soft surface can absorb sound and reduce reflection of
sound
Can reduce reflection of sound so sound will be
clearer/reduce echo
Loud speaker can act as coherent sources for
constructive inteference
Strong sound can be heard
Sound with high frequency might break the glass
Audience can enjoy better presentation without
disturbance
60. Explain the suitable design of retaining wall to protect the ship at the harbor
Suggestion
Build concrete retaining wall
Retaining wall should be curved and uneven surface
Build retaining wall in front of the bay
Retaining wall has gap
The gap at retaining wall is narrow( smaller than
wave length)
There are slope at the bottom of retaining wall
Retaining wall should be build higher
Build the jetty at bay
Explaination
Can withstand impact of the wave, difficult to crack
Prevent reflection of wave back to the ship
The wave are calmer at thr region
Diffraction will occur
The greater the curvature of wavefront will occur.
Amplitude after passing gap is smaller
At shallow region, the wavelength of wave is smaller, so
the velocity of the wave smaller
To ensure no spill over of wave
The wave at bay is calmer
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61. Explain the characteristics of parabolic radar system to detect signal from satellite communication.
Suggestion
Large diameter size of parabolic disc
Type of wave transmited is Microwave
The distance of the signal receiver from the centre of
parabolic disc is the same as the focal length
Place parabolic disc higher from the ground
Place parabolic disc at clearplace
Explanation
Able to receives more electric signal
Has high frequency, high energy, short wavelength so it
is easy to be reflected
The signal can be focus to the centre of the parabolic disc
The signal with not be block by trees or anything and the
signal easy to be detected
No signal disturbance
CHAPTER 7
62. Suggest the suitable lamp that can be use in the library, cheaper yet become the room brighter
Suggestion
Lamp with parallel circuit
Attach shiny reflector
Low power lamp
High efficiency lamp // fluorescent
Long life span lamp
Low price lamp
Explanation
If any lamp were burn out, others can still be used
Can reflect light more, no need to install more lamp, the
room will become brighter.
Safe cost
The room looks brighter
No need to replace often
Save money
63. Explain the modification of menthol bulb lamp to efficient lamp to be use in study room.
Suggestion
Use the fluorescent lamp not a filament bulb
Bigger cover with white colour
Use the adjustable stand or portable
Connect with the earth wire
Use an energy saver lamp
Explanation
Fluorescent lamp use less power and economic (consume less
power) compare to filament bulb.
Less reflection on eyes and absorb less heat energy and good
heat reflector
The height of the lamp can be adjusted can be used anywhere
Avoid short circuit and damage on the bulb
Produce same brightness with less power consumption
64. Suggest the suitable design of fuse to protect an electrical equipment which is label 240V,2400W
Suggestion
Explanation
Less space/to carry a limited electrical current/less mass
hence low heat capacity/shorter time to heat up to melting
point and blow
Can withstand higher temperature because spark created by
high voltage.240V can be huge
Maximum rating must be sligthly higher than normal current
For fast blow/melting faster when excessive current flow/easy
to cut the current flow
The fuse wire easily heated,melt and break the circuit
Good electric conductor
Does not interface with other function
Thin fuse wire
Ceramic cartridge
Fuse rating is 13A
Low melting point
Low specific heat capacity
Metal is used
Resistance to oxidation
65. You have to choose one of the cables to be used in the National Grid Network. Explain the suitability of each of
the characteristics of the cables.
Suggestion
Diameter should be large
density should be low
The rate of expansion should be low
The melting point should be high
Explanation
To reduce the resistance of the cable
The cables will be lighter and can be supportedsecurely
So thre is less expansion and less sagging in the cables during
hot days
So the cables does not melt in high temperature
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66. Explain the characteristic of electric pylon and the cable taht been use for electric transmission
Suggestion
Material: steel alloy
V shape steel alloy
Trust and supprt join
Made from small diameter and laminated wire
Cable made from low density material
Explanation
Strong,will not break easily
Not too heavy
Can support bigger weight
Reduce addy current
Cable is not heavy/ light weight
67. Investigate the characteristic of electric oven that can toast more cupcakes at less time
Suggestion
The space inside oven is build bigger
Increase the number of resistance heater at the top
and bottom
The wall is made of good insulator
Fix a fan inside the oven
Internal space of oven is painted silver
Fix the step up transformer
Explanation
It can fil up 180 slices of bread
So it can supply enough heat
Tyhe heat will not lost to surrounding
Heat energy releaswed can spread uniformly in oven
So the heat will radiated at wall and reflected back
completely
Oven can receive higher voltage and can function with
higher power
68. Explain the designof electric kettle
Suggestion
Material of heating is made from nichrome
High number of loop
Use high power
High melting point coil
Low rate of rusting
Use thermostat
3 plug in
Explanation
To produces high heat energy
To increase surface area so that more heat is released
To produce more heat energy in the coil
Nit easy melt under high temperature
Does not get rust easily
When temperatures reach 100oC
If short circuit the overload current flows to earth(for
safety reason)
69. Design incubator used to hatch eggs
Suggestion
Parallel circuit
Multi storey rack
Using fan
Bulb with same brigthness and power
Using alarm
Explanation
When one bulb damage the another bulb still function/heat can
distributed uniformly
More eggs can be arranged
heat can distributed uniformly
heat can distributed uniformly
To ensure that correct timing is employed in the hatching of eggs
70. Design circuit for cabin or house
Suggestion
connected in parallel
Fit fuse at the live wire in the fuse box
Earth connection to the metal case of
electrical appliances
Use low power lamps / install fluorescent lamp
Regularly cleaning and removing dust from the
air filters of air conditioners// Do not put more
water in a kettle than needed for hot drinks
Explanation
Allow each electric appliances to be switched on and off
independently
To stop the flow of current by melting when a high voltage
of electric current flows through the circuit // switches itself
off very quickly if the current exceeds e.g. 15A (for 15A mcb)
Earth wire connected to earth, so that when a fault occurs and
a current flows through the live wire and the earth wire, the
fuse in the live wire will blow and cut off the supply. It will
protect a person who may touch a faulty or live appliance
To save the energy
To save the energy
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CHAPTER 8
71. Suggest modification that need to be done on dc motor to increase efficiency of the motor.
Suggestion
Low density material
Increase the number of turns in
the coil
Use high strength of magnets/
Add more magnets
More segments
Increase the magnitude of
current
Explanation
Coil hass smaller mass/ lighter
Can increase magnitude of force/ higher electromagnetic field strength
Increase the strength of magnetic field
Coil rotates smoothly
Can increase the magnitude of force/ can increase the strength of magnetic
field
72. Investigate the design and the characteristic to improve the efficiency of transformer.
Suggestion
Use soft iron core
Laminated core
Use thick wire
Use copper wire to make coil
Wind the secondary coil on top of the primary coil
Explanation
Easy to magnetized and demagnetized
Less eddy current or reduce energy lost
Reduce the resistance or more current flow
Low resistance or reduce the lost of heat
Reduce leakage of field lines
73. How to design a moving coil ammeter that can function better and able to detect small change of current?
Suggestion
Use stronger magnet
Use curve magnet or concave
Use cylindrical core
Use soft iron core
Use linear scale
The sensitivity of moving coil
galvanometer can be increased by
increasing the strength of the radial
magnetic field
Using hairspring of lower stiffness
Use lighter pointer
Use a coil of a lighter mass
Increase the area of coil
Explanation
Strong magnetic field or larger rotation
Produce radial magnetic field/to get linear scale
To supply uniform magnetic field
To concentrate the magnetic field
The angle of rotation is linear
Increase the force between the current carrying coil and magnetic
field
Smaller opposing force to stop turning of coil
Smaller inertia easier to move
Smaller inertia able to move easily
More changes of magnetic flux,a bigger force are produce
74. Suggest and explain the build of adaptor to charge the 8V handphone from 240V power supply.
Suggestion
Use step down transformer
Ratio of turns 30 : 1 // 240V:8V
Use four diodes
Full wave rectifier
Using a capacitor
Explanation
Able to reduce voltage
Can reduce voltage from 240V to 8V
Full wave rectification
To convert au current to dc current
To smooth output current (steady direct current
CHAPTER 9
75. Suggest and explain the build of adaptor to charge the 8V handphone from 240V power supply
Suggestion
Use step down transformer
Ratio of turns 30 : 1 // 240V:8V
Use four diodes
Full wave rectifier
Using a capacitor
Explanation
Able to reduce voltage
Can reduce voltage from 240V to 8V
Full wave rectification
To convert au current to dc current
To smooth output current (steady direct current
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76. Consult and modified the automatic switch light (diagram A) above which can switch on at night and switch off
during morning to be automatic switch on fire alarm when there are fire , explain using diagram and the
function of component.
Suggestion
Change R1 to termistor
Change LED with alarm// siren
Change LDR with R1
Explanation
Thermistor can be detect heat from fire
Able to produce sound of alarm if fire is detected
During fire, R1 has greater resistance compare to LDR so,
no current flow
When the temperature is high, the resistance of thermistor is low. This will increase the voltage acroos R1. So,
currnt will flow to the base of transistor , than the transistor is switch on followed by greater increase in collecter
current. The alarm will switch on.
12V,24W
77. Suggest the modification need to be done to the circuit in Diagram C so that it can function as automatically
fire alarm switch that need high voltage.
Suggestion
Replace LDR with thermistor
Replace bulb with siren/bell
Connect relay switch to output transistor
Interchange the position of resistor R and thermistor
Use 240 V power supply
Explanation
To detect heat when temperature is high
To produce sound
To switch on the siren
To increase base voltage//voltage across R//base current
Siren is function as high voltage
78. Modified the circuit 240V and Np = 4000 turns circuit to switch on 12V d.c radio.
Suggestion
Step-down transformer
Ratio of turns 20 :1 // 240:12 Np = 4000 turns and Ns
= 200 turns
Using four diodes
Using a capacitor
Explanation
Capable of reducing potential difference / voltage
Reduce potential difference 240V to 12V
Full wave retification
To smooth out output current // produce output to
steady direct current.
79. Moving coil microphone
Suggestion
use thin diaphragm
Use strong material
More number of turns of coil
Thicker diameter of wire of coil
Using more powerful magnet
Explanation
Easy to vibrate
Not easy to break
Increase the rate of change of magnetic flux linkage // The
magnitude of the induced current or is also increased
reduce the resistance of the coil
to increase the strength of the magnetic field.//Increase the rate
of change of magnetic flux linkage//The magnitude of the induced
current or induced electromotive force is also increased
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CHAPTER 10
80. Explain the suitability of characteristic of radioisotopes to be used as treatment in brain tumor radiotherapy?
Suggestion
Short half life
Explanation
Radioactive is dangerous substance, short half
lfe can decay faster
Gamma can kill cancerous cell and can penetrate
skin of patient
Minimum damage to tissue organ
Easy to dissolve
Can penetrate easily
Gamma ray radiation
Low ionozing power
Liquid state of matter
High penetrating power
81. Suggest and explain the safety ways, which are required when handling radioactive substance.
Suggestion
Use thick lead box
Use forceps / robotic hand
Wear photographic film
Wear plumbum safety suit
Use siren
Packed into concrete drum and buried underground
Always place GM detector nearby
Label the radioactive container with symbol
Explanation
Radioactive rays evem gamma cannot pass through
Avoid direct touch
Able to detect exposure radiations
To protect the body from expose to radiation
Faster warning when leakage
Prevent the radioactive waste discharge to environment
To detect the amount of radioactive nearby, for safety
Easy to detect radioactive substance
82. Explain the suitability of characteristic odf radioisotope to be use in controliing the population of pest
Suggestion
Use gamma ray
Solid state of matter
Long half life
High penetrating power
High ionizing power
Explanation
Able to mutate the insect
Easy to handle
Last longer
Able to penetrate thick object/material
Able to change// mutate the biology of insect
83. . Explain the suitability of characterisitc of radioisotopes to be used in th trace of water pipeline.
Suggestion
Short lhalf life
Few hour half life
Beta particle or Gamma ray radiation
Liquid state
Explanation
Radioactive is dangerous substance, short half life can
decay faster
- Enough time for worker to detect the pipe
leakage
- Radioactive uis dangerous
Can penetrate pipe and soil, can be detected
Can be inject and dissolve into water
84. Suggest the design of nuclear reactor.
Suggestion
Explanation
Use uranium-235
Nuclear fission
Boron or Cadmium rad use as control rods
Use moderator (graphitr)
Bulid thick concrete wall
Coarbon dioxide or water is use as coolong agent
Use steam
Use as nucler fuel
A lot of heat will produce
To control the rate of nuvlear fission and to stop the radiation
To slow the motion of neutron to the best reaction rate. So
the rate of nuclear fission can be controlled
Lead or thick concrete wall can prevent the escape of
radioactive rays, keep the radiation inside the reactor
To remove heat of reaction for turbine generator. This
produce steam as heat carrier
To turn the turbine and able to generate current
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85. Explain the suitability of charactersitic of radioisotopes to be used in sanitiza medical equip,ent
Suggestion
Gamma ray
Longer half life
Silid state of matter
High penetrating power
Explanation
Able to kill ant virus/ bacteria
No need to change radioactive frequently
Easy to handle
Able to penetrate any equipment to sanitize
86. Explain the suitability of characteristics of radioisotope to be used in detecting the position of blood clot in
veins (Deep vein thrombosis)
Suggestion
Use liquid state of matter
Short half life
Use beta ray
Low ionizing power
Explanation
Able to inject into patient body, dissolve easily
Active in body in short time
Able to penetrate skin
Minimum damage to tissue organ
87. Explain the suitability of characteristics of radioisotope to be use in the trace of blockage in the kidney patient.
Suggestion
Use Iodine-123
Gamma ray
Low energy
Liquid state of matter
Short half life
Explanation
Used as nuclear imaging tracers to evaluate the anatomic
and physiologyc function
Able to penetrate trough body, bones and be detected
Do not cause serious damage in cells
Easy to inject to patient body
Active in body in short time
88. Explain the suitability of characteristics of radioisotope to be use in control the thickness of paper in factory
Suggestion
Long half life
Beta ray
Solid state of matter
Explanation
Can be used for long time, no need to replace frequently so,
it save cost
Can penetrate paper and be detected
Easy to handle
89. Explain the suitability of characteristics of radioisotope to be use in control the thickness of aluminium sheet in
factory.
Suggestion
Long half life
Gamma ray
Solid state of matter
Explanation
Can be used for long time, no need to replace frequently7
so, it save cost
Can be penetrate aluminium sheet and be detected
Easy to handle, does not spill
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MAKING DECISION-SECTION C
Soalan ini berada di dalam Section C. Cadangan dan alasan dalam soalan ini juga boleh menggunakan contoh
jawapan dalam soalan Modification.
90. The transmission of electricity over the National Grid Network uses high voltage cables. You are assigned to
study the characteristics of cables which could be used as transmission cable. Table 12 shows the
characteristics of four transmission cables. Determine the most suitable transmission cable to be used and give
reasons for your choice.
Cable
Resistivity /Ωm-1
Density / kg m-3
Cost
Rate of thermal expansion
P
Q
R
S
3.0 x l0-7
1.8 x l0-8
7.5 x l0-7
7.0 x l0-8
5 x l05
2 x l03
8 x l02
4 x l03
Low
Medium
High
Medium
High
Low
Medium
High
Jawapan
Characteristic
Low resistivity
Low density
Low cost
Low rate of thermal expansion
Cable Q
Explanation
To reduce heat loss in the cables
The cables will be lighter
Cost of project will be lower
The cables will not expand under hot weather
Low resistivity, low density, medium cost, low rate of thermal
expansion
91. You are required to build a hydrometer that can be used to measure densities of concentrated acids.Table
11.1 shows the characteristics of 4 types of hydrometers L, M, N and O. Decide which hydrometer is most
suitable and give reasons.
Hydrometer
L
M
N
O
Type of material
of hydrometer
Diameter of capillary
tube/ cm
Density of shots/
kgm-3
0.5
2.0
0.5
2.0
1000
1300
9800
8000
Plastic/Plastik
Plastic/Plastik
Glass / kaca
Glass/ kaca
Diameter of bottom
bulb/ cm
1.0
3.0
3.0
1.0
Jawapan
Characteristic
Material made from glass
Small diameter of capillary tube
High density of shots
Big diameter of bottom bulb
Choose N
Explanation
Glass does not corrode with acid
To increase the sensitivity of the hydrometer
Makes the hydrometer stays upright
To obtaine a bigger upthrust.
N is made from glass, has small diameter of capillary tube, high
density of shots and a big diameter of bottom bulb
92. As a researcher , your duty is to study the characteristics of a material to make a water heater. You are given
four choices of metal type T, U,V and W. The table below shows the characteristics of the four
metals.Determine the most suitable metal to be used as the material to make the heater and give your
reasons.
Metal
T
U
V
W
The cross sectional area
Smaller
Larger
Smaller
Larger
Melting Point
Low
High
High
High
Specific Heat Capacity
High
Low
Low
Low
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Length
Long
Short
Long
Short
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Jawapan
Characteristic
Smaller surface area
High melting point
Low specific heat capacity
Long (coiled) metal
Choose V
Explanation
the resistance is higher
not easy to melt
the temperature arises shortly
to increase the resistance
because it has,smaller surface area, high melting point, low
specific heat capacity and long metal
93. You are given four choices of metals P, Q, R and S. The table below shows the characteristics for the four
metals. Determine the most suitable metal to be used as the material to make the boat and give your reasons.
Metal
Shape
Density
P
Q
R
S
Streamlined
Oval
Circle
Streamlined
900
452
387
500
Specific Heat
Capacity
Low
High
Low
High
Strength
High
High
High
High
Jawapan
Characteristic/cirri
Streamline / larus
Density /ketumpatan rendah
Specific heat capacity high /
High strength / Kekuatan tinggi
Choose S
Reason/Sebab
reduce the resistance of water/
higher buoyant force/ daya apungan tinggi
absorbs heat slowly/serap haba dengan perlahan
Difficult to damage / sukar rosak
because its streamline,low density, high specific
heat capacity and high strength
94. A student plans to fix a lamp in his room. Table 12.1 shows the features of 4 different types of lamps. Explain
the suitability of each feature in Table 12.1 and then determine the most suitable lamp to be used. Give a
reason for your choice
Type of lamp
Compact fluorescent lamp
Filament lamp
Long fluorescent lamp
Round fluorescent lamp
Power
18 W
75 W
20 W
24 W
Efficiency
50 %
12 %
45 %
40 %
Life Span
7000 hours
1000 hours
14000 hours
10000 hours
Price
High
Low
Medium
High
Jawapan
Characteristic
Low power lamp
High efficiency
Long life span
Low price
Long fluorescent
Explanation
Safe cost//electric bill
The room looks brighter//high output power//less power
wastage
No need to replace often
Save money/cost
Low power with highest efficiency, long hours of life span and
low price
95. Table 11.1 shows 5 materials which can be used to make an optical fibre. You are asked to investigate the
characteristics of the materials in Table 11.1 which could be used to make the optical fibre.
Explain the suitability of each characteristic and hence, determine the most suitable material to be used to
make the optical fibre. Give a reason for your choice.
Material
Refractive index
% of light energy absorbed
Rigidity
Strength
P
Q
R
S
T
1.75
1.80
1.70
1.52
1.48
2%
10 %
2%
3%
10 %
Strong
Weak
Weak
Strong
Weak
Weak
Strong
Strong
Strong
Weak
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Jawapan
Characteristic
High refractive index
Small amount of light energy being absorbed
by the material
Material with weak rigidity
Material with great strength
Material R
Explanation
Total internal reflection can occur easily
The object under observation can be seen clearly // more light
can be transmitted
The optical fibre can be bent easily
The optical fibre can last longer/not easily spoil
High refractive index, low % of light energy absorbed, weak
rigidity and great strength
96. You are asked to investigate the characteristics of hot air balloon as below. Explain the suitability for each
characteristic for the hot air balloons and then determine which hot balloon will move up the fastest into the
air. Give a reason for your choice
Jawapan
Characteristic
Volume of the balloon is high
Density of the balloon material is low
Gas temperature is high
Total of mass is low
Choose Q
Explaination
Displace a larger amount of air/
Produce a higher buoyant force.
Lower mass/Light
Produce a maximum expansion of balloon.
Upwards resultant force is higher/ Balloon move upwards faster.
Because it has a high volume,the density of the balloon material is
low,the gas temperature is high and the total mass is low.
97. Table 11.1 shows the characteristics of five types of materials that can be used for making the soles of the
trekking shoes. You are asked to study the characteristics of the materials shown in Table 11.1. Explain the
suitability of each characteristics in Table 11.1 and then determine the most suitable material to be used. Give
a reason for your choice.
Type of
material
P
Q
R
S
T
Density
(Kg/m -3)
820
700
720
750
880
Number of studs x Area of 1
stud
6 x 30 cm2
8 x 30 cm2
5 x 30 cm2
4 x 30 cm2
3 x 30 cm2
Expansion
effect
Low
Low
Medium
High
High
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Ability to
stretch
Good
Good
Average
Poor
Poor
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Characteristic
Low density
Many/fewer/very few studs
Expansion effect is low
Ability to stretch is good
Reasons
Small mass/light
Gives extra/higher grip
Always fits/Does not loosen when hot.
Less stress on the feet/Can be pushed in all directions/
Can walk on uneven surface.
Because it has a low density,many studs,low expansion effect and
good ability to stretch.
The most suitable material is Q
98. Table 12.2 shows the characteristics of five radioisotopes P, Q, R, S and T. As a factory engineer, you are
required to determine the most suitable radioisotope that can be used by the system to ensure the volume of
guava juice is uniform.Study the characteristics of all 5 radioisotopes and explain the suitability of the
aspects.Determine the most suitable radioisotope and give the reason for your choice.
Radioisotope
Radioisotop
P
Q
R
S
T
Half life
Separuh hayat
Types of ray
Jenis sinar
State of matter
Keadaan jirim
Ionising power
Kuasa pengionan
7 hours
10 days
100 days
10 years
30 years
alfa
beta
gamma
gamma
beta
solid
liquid
solid
liquid
solid
high
moderate
low
high
low
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Characteristics
Has a long half-life
Emits beta
Solid form
Low ionising power
Radioisotope T
Explanation
Can be used for a long time hence save cost
Can penetrate box and liquid and is less
dangerous than gamma
Easy to handle and contain.
Does not change the state and taste of juice.
It has long half life, emits beta, in solid form and has low ionising power.
99. You are assigned to investigate the design for the location to keep the boats andthe characteristics of the
retaining wall as shown in Diagram 12.2 based on the following aspects:
- the location to keep the boat
- material used for the retaining wall
- the height of retaining wall
- size of slit
Explain the suitability of the location and the characteristics of the retaining wall and determine the most
suitable design to keep the boat safely.
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Characteristic
Bay
Concrete retaining wall
High wall
Smaller opening/aperture / slit of
retaining wall
Choose P
Reasons
Wave is calmer
Stronger/ / lasting
Prevent high wave
Diffraction obvious //low wave energy
At bay, concrete retaining wall , high wall and smaller slit
100. Diagram 11.4 shows five designs of ‘Newton’s Cradle’, P, Q, R, S and T, with different specifications. You are
required to determine the most suitable design to make the ball at the end swings up to higher level and at
bigger speed. Study all the five designs from the following aspects:
− The arrangement of the balls
− The type of material used to make the balls
− the number of string used to hang the balls
− the position of the ball to start the oscillation
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Characteristic
The balls touch each other
The type of material used to make the
balls is steel
Two strings used to hang each ball
High position of the ball
The most suitable design is Q
Reasons
This will reduce losses of energy which will reduce the speed of the
balls
Steel balls are hard and produce highly elastic collision. Energy can
easily propagates through the intermediate balls.
This string arrangement restricts the balls’ movements to the same plane.
the position of the ball to start the oscillation
High potential energy and will change to high kinetic energy. The last end
ball will swing at bigger speed.
because the ball s touch each other, made from steel, use two strings
attached to each ball and the initial position of the ball is high
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