Essay questions
Problem solving and
decision making
1. INTRODUCTION TO PHYSICS
Characteristics of instrument to measure diameter
of ball bearing
Consistency is higher
The reading is more
consistent
Accuracy is higher
Can give measurement
closer to actual value
Sensitivity is higher
Can detect small
changes in value to be
measured
Has no zero error
To increase accuracy of
reading. Every
measurement must be
minus with zero error
Has no parallax error
Eye must be
perpendicular to the
scale to avoid parallax
error
2. FORCES AND MOTION
Method to reduce the impact of impulsive force in
egg’s drop competition from a height. (Mk)
The egg’s casing
Lengthen the time of
made from soft
impact
material
Use parachute
To slow down the egg drop
The egg’s casing
Absorb the impact//
part that hit the
lengthen the time of
ground when landing impact.
made from easy to
crumple material
Characteristics of student to be in a basket ball
team. (Phg)
Mass is smaller
More agile/ can change
direction/increase speed
easily
Taller
Easy to shoot goal
Responding time fast Easy to catch ball
Powerful
More energy/not tired
easily
Faster
Can
block/attack/run/defence
faster
Suitable characteristics of rope used for parachute.
(Pls)
Use a dynamic rope
It is softer and could
prevent injury.
A lower density
It is lighter
Higher snapping
Not easy to snap
force
A rope with smaller
It will occupy less space.
diameter
Suggestion to design a water rocket.
Made from tougher
Not easy to break
material
Aerodynamic/streamline Reduce air friction
shape
Angle of launching is
The rocket can travel
45o
Amount of water is 1/3
of the whole volume
Attached fins to the tail
of the rocket
very far
To increase momentum
and impulsive force
Rocket can move
smoothly and stable
Characteristics of the spring cradle
Low spring constant
Less stiffer and the spring
can oscillate with low
frequency
Low density
Small mass and lighter
Low rusting rate
Not easy to rust and lasts
longer.
Two springs are
Can withstand a heavier
arrange in parallel
baby
Put string in the
To prevent the baby from
spring
falling down in case if the
spring breaks
Explain safety features of the car.
Safety belts.
To prevent the passengers
from being thrown forward
due to the inertia when
accident occurs.
Air bags
Cushion the passengers
from direct impact with the
steering when accident
occurs to reduce the
impulsive force.
Easy crumpled
To reduce impulsive force.
steering.
Front and rear
To extend time of impact
crumple zone.
so that the impulsive force
will be reduced.
Use stronger spring
To reduce vibration when
for the suspension
the car being used off road
system
Anti-scattering
Will not harm the
windscreen
passengers and driver
when it breaks.
Head rest
To keep the position of
head when the car being
hit from back.
Passenger safety
To prevent the car from
steel cage/cell built
being crumpled when it is
from reinforced steel
overturned.
Way so that the pole vaulter can jump higher and
lands safer.
Run faster
Increase the kinetic energy
Use elastic pole
Produce higher elastic
potential energy
Use tight sport wear
Reduce air friction
Use thick mattress
Increase the interval of
with soft surface
impact on landing, thus
reduce the resultant
impulsive force
Landing on the back
Increase the surface area
and reduce pressure
Use a spike
To run faster and increase
kinetic energy
Modify a normal car into a racing car.
Use of higher power
To produce high thrust
engine
force
Use of strong
Will not break/damage
composite material
easily
Use of engine which
Will not damage at high
is able to withstand
temperature
high temperature
Use of low density
To have smaller mass
material
Aerodynamic shaped
Use of spoilers at
front, rear and side
of the car
Use of wider tires
Use of hydraulic
brakes
Center of gravity of
the car is lower
Additional safety belt
Improve the safety
steel cage/cell with
more reinforced steel
To reduce air resistance
To create a downward
pressure (Bernoulli’s
effect) to prevent the car
from being lifted upward at
high velocity
To produce better grip to
the road
So that the car can be
stopped faster
To increase the stability of
car
To prevent the driver being
thrown forward during
collision.
To prevent the car from
being crumpled when it is
overturned.
Method so the pole vault athlete can jump higher
and safer.
Bend the body when
To reduce the air friction
running to take off.
so that the acceleration will
be greater.
Wear tight clothes
To reduce air resistance
Use spiked shoes
To give stronger grip for
greater speeding
Pole is made from
The potential elastic
soft but stiff material
energy is high thus the
height of jumping can be
increased
Pole is made from
Will not break easily
tougher material
Put soft and thick
To increase the time of
mattress on the
impact and reduce the
landing pit
impulsive force
Land on the back
Increase the surface area
and decreases the
pressure inverted.
Design of the water rocket so that it can fly further
and faster.
High volume / mass
Can increase the
of water
momentum to the back
thus increase the explosive
force
Soft drink bottle
Decrease the mass and
increase the explosive
force
Add wing on the
Rocket fly in stable
bottle
Add something to
Reduce the air resistance
the part of the bottle
to make it sharp and
aerodynamic
Add weight to the
Rocket can move straightly
head of the rocket
and the head move 1st
Use a higher power
Pushing force to the back
pump
is high, momentum to the
back is high
Flying degree is 45
The flying distance is
degree
longer
Modify the ordinary motorcycle to become a racing
motorcycle
Use softer and wider
To strengthen the grip of
tires
the tires on the road
Use an aerodynamic
To reduce the air
shape
resistance
Low center of gravity
To make it more stable
Made from low
More lighter and can
density materials
increase the acceleration.
Use heavy engine
and place it in the
middle of the
motorcycle
Use powerful engine
Use front and rear
disc brakes
The motorcycle is more
stable
To produce high thrust
force.
So that the motorcycle can
be stopped easily.
Design of the safety belts
Wider
Large surface area will
reduce pressure to the
driver/passenger
Can be expanded
To reduce impulsive force
Made from tougher
Does not break easily
material
Made from non-stiff
So it is soft and
material
comfortable to use
Design of the satellite that falling back to the earth
so that it is not damage.
Made from material
Not easily become hot.
that has higher
specific heat
capacity
Aerodynamic shape
To reduce air resistance
Protected by a good
To prevent the heat
heat insulator
reach/enter the inner part
of the satellite
Made from low
The mass will be smaller
density material
so the impulsive force is
reduced
Made from tougher
Not break easily
material
Attached with
To reduce the velocity
parachutes
Attached with
So that the satelite is not
cooling system
become hot/melt easily
Design of springs for athlete’s exercise purposes
Parallel arrangement
To increase the stiffness of
the spring.
Short in length
To reduce the extension of
the spring.
Small in diameter
Greater force is required to
stretch the springs.
Covered with plastic.
Will not harm the athlete if
the springs are broken.
Made from nonCan be used for a longer
rusting materials.
time/durable.
Fix with holder at the
Can be easily be held and
end of the spring
stretched
Fix an elastic rope in
To prevent the springs
the springs
from being stretched over
it’s elasticity limit.
Modification to the bus to improve the safety of the
passengers.
Attach safety belts.
To prevent the passengers
from being thrown forward
due to the inertia when
accident occurs.
Air bags
Cushion the passengers
from direct impact with the
front seat when accident
occurs to reduce the
impulsive force.
Front and rear
To extend time of impact
crumple zone.
so that the impulsive force
will be reduced.
Use stronger spring
To reduce vibration when
for the suspension
the car being used off road
system
Shatter proof
windscreen and
window panels
Head rest
Passenger safety
steel cage/cell built
from reinforced steel
The bus is made
from tougher
material
Break into small pieces
with blunt edges and will
not harm the passengers.
To keep the position of
head when the car being
hit from back.
To prevent the bus from
being crumpled/collapsed
when it is overturned.
To avoid the bus being
dented when involved in
accident
Characteristic of spring to be used as a spring
cradle. (Ktn)
Springs are arranged
Can support higher load.
in parallel
Use stiffer spring
Not easily broken/ spring
constant is higher.
Stainless steel
Can be used for longer
time.
Shorter spring
Spring constant is
higher/stiffer.
Characteristics of arm exercise equipment made
from spring that is suitable to use (J)
Spring made from
Can be used for longer
stainless steel
time.
Made from steel
The spring is stiffer
Spring made from
Wire not break easily
thicker wire
Spring with smaller
Can withstand bigger
diameter
force, more stiffer
Modification of a fisherman boat so it can be used
for deep-sea fishing. (MRSM)
Shape of the boat is
Less water friction.
streamlined
Made from tougher
Can withstand big wave
material
Stainless steel
Can be used for longer
time. Less maintenance
Use ultrasonic wave
More energy and can
penetrate deeper in the sea
Bigger cool room
Can put a large amount of
fish for longer time.
Suitable characteristics of tractor used to do heavy
works
Use larger tires
Larger contact area
produces low pressure and
the tractor will not sink into
the ground
Larger mass
Larger inertia
Low centre of gravity
More stability
Use liquid in the
Liquid cannot be
hydraulic system
compressed
Characteristics of spring to be used as the
motorcycle spring
Smaller diameter of
Enough space to place the
spring
spring to the motorcycle.
Higher elastic limit
Can support more load
Higher spring
Small compression of the
constant
spring due to bigger load
Smaller natural
To reduce bumping effect
frequency
Essay questions
Problem solving and
decision making
3. FORCES AND PRESSURE
Specification of watercraft/ship.
Cross sectional –
Reduce water resistance.
Front side narrow
and pointed
Hull made from
Lighter, stronger and not
aluminum
corrode.
Hydrodynamic
Withstand shock waves.
shape.
Reduce water resistance
(Stream-lined)
Diesel engine
Cheaper and powerful
Specification of submarine. (MRSM)
Use nuclear energy
Can be used for longer
time
Use ballast tank
Can float and submerge
easily
Fix with periscope
Can look at the surface of
the sea without floating on
the surface
Use ultrasonic wave
Can penetrate further
for radar
Characteristic of ship that can carry heavy loads.
(SBP)
Streamlined shape
Reduce water resistance
Made from high
Able to withstand bigger
strength metal
wave
Ship base cross
Abele to displace out more
sectional is wider
water to gain more buoyant
force
Volume of the air
Can displace out more
space in ship is
water//increase the volume
bigger
so overall density is lower
than water
Characteristics of hydraulic brake.
has a high specific
Plate not easily heat up
heat capacity
High boiling point
Not easily boil at high
temperature
Fluid that
Pressure can be transfer
uniformly to whole the fluid
Use non-corrosive
To not destroy the brake
fluid
system
Brake made up of
Not easily get rust
stainless steel
Design of a buoy on the sea surface
Painted with bright
Can be easily seen in the
color
morning and at night
Fix lamps on the
Can be easily spotted at
buoy
night
Made of thick and
Will not easily split and
hollow material
waterlogged
Fix small flags on the Can be easily split and
buoy
waterlogged
Tied with ropes to
To prevent the float from
the seabed
sweeping away
Not made from metal
To prevent the float from
rusting and can be used for
a long time.
Hollow and big in
To have buoyancy and
size
floats
Modification of a pesticide sprayer into painter
sprayer.
Use a compressor
Provide high air pressure
with high ac voltage.
continuously.
Use compressor
To give high air pressure
which produce high
and produce stronger
pressure.
spray.
Made from low
Light and can be bring to
density materials
anyway
Use materials that
Do not rust/corrode easily
resist to
and last longer.
corrosion/rusting.
Use stronger
Do not easily broken or
materials
damaged
Use a bigger paint
Enable to store more paint.
container.
Adjustable nozzle
Can control the size of the
sprayer.
spray.
Use longer nozzle
Can spray the hidden part.
spray.
Design for the water tank to store a large amount of
water
Made from
Makes the tank stronger
composite materials
and does not break easily
and fiber
Made from low
More lighter
density materials
Thick wall at the
To enable the water tank to
bottom of the tank
withstand the large water
pressure at the base of the
tank
The water tank is
So that the tank will not
placed on the thick
sink into the ground
concrete floor
Large tank base
To reduce pressure and
prevent the tank from
sinking into the ground
Build the water tank
To increase the pressure of
at higher placed/
the water
build a tall design
Build larger water
Can stored more water
tank
Modification to the hydraulic jack to enable it to lift
mass of greater quantity
Use piston of bigger
Can support greater force
cross-sectional area
(weight)
Use low density
Very light and easy to carry
material
Non-compressible
Piston can be lifted up
liquid
Longer handle
Less effort needed to press
the small piston.
Apply released valve
Liquid can flows into small
between small and
reservoir.
main reservoir.
Use stronger metal
Not easily broken.
Use non-corrosive
Will not corrode metal and
liquid
long lasting.
Characteristic of an automatic tennis ball shooter.
Small spring
To ensure that the elastic
diameter
potential energy is higher.
Thicker spring wires
So that spring constant is
higher/more elastic/ball
can be shot out at a high
velocity.
More number of
So that the compression
spring coils
length is longer.
Low density of tennis To ensure that it moves
ball is used
faster and further.
Suitable characteristics of a wings to be installed
with the body of the aircraft
A shape of crossTo produce the speed of air
section which is
flow above the wings to be
upper side is longer
higher than the bottom
than the bottom
area.
The area of the wing
To produce larger lift force
is larger
Made from low
Less weight//very light// to
density material.
produce more upward
resultant force.
The difference in
To produce higher
speed of air is higher
difference in pressure
Design of the astronaut’s suit
White color/shinning
To reflect the cosmic ray
Made from tougher
Not easily torn
material
Made from non-stiff
So that the astronaut can
material
move easily.
Lined with
To avoid the penetration of
lead/plumbum
radioactive radiation.
Use photographic
To check the exposure to
badge.
the radioactive radiation of
the astronaut.
Put on safety space
To allow the astronaut to
helmet made from
look at his surroundings.
tough glass
Modification of hydraulic jet to overcome bigger
force
Increase the surface
area of bigger
cylinder
Decrease the smaller
surface area of the
cylinder
Hydraulic oil that will
not evaporate easily
Larger base area of
hydraulic jet
Made from harder
alloy
Made from low
rusting effect object
Can easily push up bigger
mass object
Can push up bigger mass
with lesser force
Not easily evaporated
when in high temperature
More stable
Not easily break when
supporting bigger mass
object
Can use for longer period
Way to increase the cleaning efficiency of cloth.
Use detergent
Remove the dirt and
moistening the cloth
Use hot water
Decrease the surface
tension of the water and
moistening the cloth.
Use automatic
Can control the amount of
mashing machine
water being used
Use pipe water (soft
Enable the soap to form
water) not well water
scum and increase the
(hard water)
cleaning efficiency
Clothes are made
To avoid the oil and dust
from materials that
stick on the clothes
can decrease the
stickness between
the clothes and the
dirt
Waterproof clothing
So that the clothes will not
become wet when we
sweat
Use more efficient
Clothes will be shivered
washing machine
along with the detergents
to remove the dirt
Use computerized
Can control the
washing machine
usage/volume of water
Suitable characteristic of hydrometer to measure
the density of concentrated acids.
Material made from
Glass does not corrode
glass
with acid
Small diameter of
To increase the sensitivity
capillary tube
of the hydrometer
High density of shots Makes the hydrometer
stays upright
Big diameter of
To obtaine bigger upthrust
bottom bulb
force so the hydrometer
can float
Suitable characteristics of metal to be used to built
a boat
Streamlined (larus) in To reduce water resistance
shape
Lower density
It will be lighter.
material
Higher specific heat
Absorbs more heat but
capacity
become hot slowly
High strength
Not easy to damage
Corrosion effect is
Not easy to rust/corrode.
lower
Modification of the balloon so that the balloon can
float and carry more passenger and has safety
features for the passenger
Use hot air/
Less dense than the
helium/hydrogen gas
atmosphere//lighter
Larger basket
Can bring more
passengers
Balloon/basket made
To reduce it weight
from low density
material
Basket fit with
Comfortable and reduce
cushion
impulsive force when
landing
Use burner
To control the height of the
balloon by producing hot
air.
Equipped with
Can be used to save the
parachute
passengers if the balloon
is not functional.
Equipped with safety
To avoid passengers from
belts
fall down.
Suggestion to built a barge (tongkang) that can
carry heavy load, faster and safer
Built from stronger
Can withstand great force
material
Lower density
Lightweight
material
Has two stage
Save in fresh and salt
plimsoll line
water
Bigger size
Can place more load
StreamlinedReduce water friction
aerodynamic shape
Specification of component in the brake system
Disc brake is made
Not easy to become hot
from higher specific
heat capacity
material
Higher melting point
Not easy to melt at high
of brake disc
temperature
Compression of
Difficult.
brake liquid
Higher hardness of
Can be used for longer
brake disc
time.
Characteristics of fluid/liquid used as a hydraulic
fluid
Higher boiling point
Not easy to boil at high
temperature
Higher specific heat
Not easy to become hot
capacity
Lower density
So the hydraulic jack will
not become too heavy
Has lower rate of
No easy to expand so the
expansion
volume will be constant
Design of hydrometer use to measure the density of
an acid solution.
Smaller and longer
Increase the sensitivity
stem.
where the scale divisions
are far apart so that small
changes in density can be
detected.
Use glass to built the
Do not erode and small
hydrometer
adhesive force.
Larger diameter of
Higher up thrust
bulb
force/displaces more
liquid/able to float easily
Use lead shot in the
Hydrometer can float
bulb
vertically and stable.
Suitable characteristic of hot air balloon which is
able to carry more passengers to a higher altitude
in shorter time.
Larger balloon size
To produce bigger bouyant
force.
Use many burners
To produce bigger flame.
Heat up the gas in shorter
time.
Use synthetic nylon
Lighter, strong and airproof
Higher temperature
Reduce the density of the
of air in the balloon
air in the ballon.
Essay questions
Problem solving and
decision making
4. HEAT
Characteristics of an ice cream container.
Use low specific heat Easy to get cold//become
capacity to bulit
cool easily.
inner box.
Smaller size of ice
Easy to carry because it is
cream box
lighter.//Easy to become
cool.
Outer box is made
It is poor conductor// It is a
from PVC plastics
good heat insulator.
Outer box colour is
Does not absorb heat from
brighter.
surrounding quickly.
Has gap between
Avoid heat from
inner box and outer
surrounding enter the inner
box and fill with heat
box.
insulator.
Suggest the suitability of material used to
determine the specific heat capacity of aluminum
Put on asbestos
A good heat insulator.
Avoid heat loss by
conduction.
Wrapped with tissue
Avoid heat loss by
paper
radiation/ to the
surrounding
Put some oil in the
Better heat contact
hole
between aluminum block
and thermometer.
Higher power
Can increase the
immersion heater
temperature faster.
Characteristic of spatula use as a kitchen utensil
(Mk)
Shape of the handle
Easy to handle
is slim
Density is lower
Its is lighter
Higher melting point
Not easily melt at higher
temperature.
Higher specific heat
Not easily become hot.
capacity
Desing of the ice container.
Lower density
Smaller mass, lighter and
easy to carry.
Higher specific heat
The container is not easy
capacity
to become hot/cold
Made from good heat To avoid heat from
insulator
surrounding enter the
container.
Shining surface.
To reflect the heat from
surrounding and avoid the
heat being absorbed by the
container.
Put a cover to the
To avoid heat from enter
container.
the container.
Design of the car radiator
Use water as a
Higher specific heat
cooling agent
capacity
Use bigger fan
Can sucked out more heat
from the radiator
Use water pump
To help in the flow of water
to the radiator
Paint the radiator
Black body can radiate
with black paint
more heat
Number of cooling
Cooling will be more
fin is greater
efficient
Characteristic of a school’s physics laboratory
thermometer. (MRSM)
Bulb is smaller
More sensitive
Rod is thicker
Stronger, not easily break.
Wall of the bulb is
Allow good heat
thinner
conduction
Capillary tube bore is More sensitive, more
smaller
accurate reading
Use mercury
Opaque and can be seen
easily
Do not stick the glass
Rod is longer
Wider range of scale and
more sensitive
Suitable characteristics of the solar cooker
Use concave mirror
Use spherical
concave mirror
Kettle is made from
metal
The kettle holder is
made from insulator
Will converges all light to
the focal point
Will converges more light
to the focal point hence
increases the intensity of
light/heat
Metal is good conductor.
Easy to handle the kettle
and not so hot
Modify/design of an efficient solar water-heating
system.
Use insulator behind
To prevent the loss of
the absorber panel
heat energy
Use an absorber
A black surface is a good
panel which is
absorber of radiation so it
painted black.
will
absorb heat faster
The pipe inside the
Metal is a good heat
plate must be made
conductor,
of metal
so it will transmit heat to
water easily
Pipe embedded in
Longer pipe will enlarge
plate must be long
surface area will absorbs
heat
faster
Use glass cover on
To trap heat energy.
the top of the panel
(energy is radiated in,
but cannot radiate out
again).
Design of the oven so that the oven will use less
electricity and user friendly
Fix a bulb in the oven Can see the cake clearly
Has stand so the
So the user can load and
oven is at eye level
unload the cake easily.
Built the oven so that Can bake large amount of
the oven has many
cake in one time.
racks
Insulate the oven
The heats will not loss to
with good heat
the surroundings.
insulator
Fit with a glass
window to the cover.
Fit a fan in the oven
Made from stainless
steel
Can see the cake without
opening the cover.
So the heat will spread
uniformly in the oven.
Last longer/durable.
Design of the hot food container.
Lower density
Smaller mass, lighter and
easy to carry
Higher melting point
Not melt easily at high
temperature
Higher specific heat
Not become hot easily
capacity
Lower heat
To avoid loss of heat to the
conductivity
surrounding.
Design of a cooking pot
Pot made from lower
Easy to become hot with
specific heat
small amount of heat.
capacity material
Lower rate of
Not easy to corrode and
corrosion.
does not contaminate the
food
Made from lower
The mass will be lower and
density material
easy to handle
Made from aluminum
Lower density and
cheaper.
Handle is made from
Not easy to become hot.
higher specific heat
capacity.
Characteristics of hot water tank.
High specific
- To ensure that it will not heat
heat capacity
up fast.
Low density
- So that its mass is smaller
and easier to be managed.
Low rate of
- So that it will not be easily
oxidation
oxidized / rust when contacts
with hot water.
Durable
- To ensure that the reservoir
will not break easily when it
is filled with large amount hot
water.
Characteristics of liquid use as a cooling agent for
engine.
Specific heat
Not easily become hot
capacity must be
high
High boiling point
Not easily boiled in high
temperature
Ph7
Will not corrode the engine
rusting low
Will not caused the engine
to rust
Characteristics of car radiator use to cool the
engine.
Large number of
To ensure that more amount
cooling fins
of heat is released at a short
period of time.
Size of the fan is
So that the radiator can be
big
cooled quickly./ Direct large
amount of air to the radiator.
Use water
Specific heat capacity of water
is high and takes time to
become hot.
Use cover with
To ensure that pressure in the
spring
radiator can be release
automatically.
Suitable characteristic of metal to be used as a
cooling fins of a motorcycle
Lower specific heat
Easy to get hot or cold
of capacity
Higher melting point
Does not melt easily
Good heat conductor The heat can be lost easily
Lower rate of
The shape of fin unchange
expansion
Essay questions
Problem solving and
decision making
5. LIGHT
How to build a compound microscope.
• Eyepiece – use longer focal length = fe
• Objective lens – use shorter focal length. = fo
• fe > fo
• Label the fe and fo
• Draw a ray diagram to show the formation of
images.
Ray diagram
Suggest suitable modification to increase the
efficiency of compound microscope. (Ktn)
Eye piece has longer
Has higher magnification
focal length than
factor.
objective lens.
Object is place
To produce real, magnified
between fo and 2fo
and inverted image
Adjusted so that
To act as a magnifying
object for eyepiece is glass
place u<fe
Distance between
To produce bigger image
lenses is > f0 + fe
from the eyepiece.
Store in cool and dry
To avoid the formation of
place
fungus.
Design an optical instrument in the double-decker
double
bus so that The driver at the lower deck is able to
see the upper deck. With cheaper cost. (Phg)
Use periscope
Cheaper than CCTV
2 plane mirrors//2
Reflect light from object
prisms
Mirrors are arranged parallel light from first mirror
will be reflected into second mirror
Light from second mirror is reflected into the
driver’s eyes
Tube or casing to hold mirror easier to handle
periscope
Mirrors are at 45o angle
How to built compound microscope.
•
Thicker lens as an objective lens, thinner lens
as an eyepiece.
•
Fo and Fe are not overlapped.
•
Light ray to form the first image.
•
First image formed shown.
•
Light ray to form final image.
•
Final image formed shown.
Diagram
Explain how to built simple periscope and suggest
modification to convert the periscope to binoculars
Draw a labeled diagram
Specification of the optical fiber use in an
endoscope for medical imaging.(Mk)
Low density
Lighter
High flexibility
Can be bent easily.
High purity
Avoid loss of signal.
Smaller in size
Can occupied in small
space.
Made from stronger
Not easily break
material
Draw a labeled diagram
Use 2 right angle
prisms
Use eye piece and
objective lens
The rays will bent through
180o
To magnified the image/ as
a telescope
How you would build a simple binocular and
suggest modification so the binocular will
produced brighter and bigger image (J)
Objective lens with
bigger diameter
Eyepiece with bigger
power
More light can enter the
binocular
higher power as a
magnifying
ying glass
Suitability of mirror use to watch over the shop
costumer. (Pls)
Concave mirror
To provide wider field view
Bigger size of mirror
To enable a wider view and
sharper image.
Hung the mirror at
Easier to look/won’t disturb
the top corner of the
the costumer
shop
Characteristics of optical fiber
Small critical angle
Internal reflection can
easily occur
High density
To have small critical angle
Stiffness is low
Can be easily bent
High strength
Will not break easily
Small in diameter
Does not occupied much
space
Modify an astronomical telescope become a
binocular.
• Astronomical telescope uses 2 convex lens.
Objective lens and eyepiece.
• Objective lens has longer fo. Eyepiece has
shorter fe.
Diagram
Advantage of binocular
• Binocular is shorter//smaller in size.
• Easy to carry.
• Produced brighter image.
Characteristics of lenses to built telescope.
Objective lens with a
Higher magnifying power
long focal length
Eyepiece with a short Higher magnifying power
focal length
Objective lens with a
Enable the light to enter
big diameter
and thus clearer the image
to be seen
Eyepiece with a
Suitable with our eye’s size
small diameter
and make it easier for us to
see
Design of fibre optics which can work efficiently
Use refractive index
So that total internal
of outer layer less
reflection can happen in
the fibre optic.
than the refractive
index of inner layer
Use high flexibility
So it can be bend
material
Use stronger
Do no break easily
material
Use thin material
Lighter/ can be used in
small area
Low density material
Lighter
Suitable characteristics of lens to be used by a
technician to repair watch.
Use convex lens
To magnify the image
% of clarity is higher
Image will be brighter and
clearer
Focal length is short
To increase the power/to
produce bigger image/
image can be focused on
the short distance
Lens has smaller
Easy to wear as a
diameter
spectacle.
Suitable design for slide projector
Use concave mirror.
To reflect dan focus light to
the slide
Use two planoThe light from the source
convex lens that
will distribute evenly to the
slide so that the image
have same power
formed on the screen is
brighter.
The distance
The image formed on the
between the slide
screen will be magnified
and real.
and the projection
lens is between f and
2f
The slide would be
So the image will be
placed inverted
upright
Essay questions
Problem solving and
decision making
6. WAVES
Suggest modification to built big hall so it is
suitable for the assembly
Bulit a dome shaped
Improf the aqoustic effect
or circular roof
of sound/accomodate more
student
Increase the number
Reduce effect of reflection
of door.
Built wall from
To avoid disturbance from
sound-proof material
outside
Inner wall made from
To avoid reflection of
soft material/use
sound.
cushion chair/curtain
Placed loudspeaker
To produce more
away to each other
constructive interference
region
Increase the number
To get sufficient amount of
of light
light.
Suggest relevant steps to be taken to build a safe
port for fishermen.
Built the port at the
The water wave is calmer
gulf
Built a wall that has a The sea wave will
narrow gap in the
undergoes diffraction and
sea
the amplitude will be
reduced
Built the wall using
Not easily to collapse
concrete
Make small hole at
To absorb the wave
the wall
energy.
Built stronger wall
To reflect the sea wave
Built higher wall
The sea wave cannot pass
through over the wall
The wall must be
So that the wavelength can
slanting
be reduce when the sea
wave hit the wall
Characteristics of waves which are use to
determine the depth of the sea.
High frequency
Higher energy and enable
sound wave
the wave to travel further
Higher amplitude
High energy and enable the
wave to send to further
places
Higher percentage of
So the reflected signal can
energy reflected from be detected easily
seabed
Rate of sound
So that the wave can be
absorption by the
easily reflected and
water is low
detected by the
hydrophone.
Suggestion to built beach resort
Built at bay
Water is calmer. Sea is
shallower
Built retaining wall
Reflected back the wave to
open sea.
Built gap in the wall
Diffraction occurs. Energy
of wave is smaller
Higher wall
The wave cannot passed
over the wall
Wall is built using
The wall will be stronger.
concrete
Characteristics of wave use to detect a school of
fish
Longitudinal wave.
Sonar sound is
longitudinal wave
Higher frequency
Has higher energy
Higher speed
Can travel faster in the sea
Higher penetrating
Can penetrate through
power
medium easily
Essay questions
Problem solving and
decision making
7. ELECTRICITY
Suggestions of material used to build heating
element.
Lower density
Light weight
Higher melting point
Not easy to melt at high
temperature
Low rate of oxidation
Can be used for longer
time.
Lower surface area.
Resistance will be higher
and produced more heat.
Used longer wire
Higher resistance and can
produced more heat
Design of pylon for transmission of electricity.
(Phg)
Use step up
Current will be smaller and
transformer to
less loss of energy
increase the voltage
before transmission
process
Use low resistance
Less loss of energy to
wire
overcome the resistance
Use low density wire
Lighter. Easy to hung on
pylon.
Higher pylon
For safety purpose. Not
reach by others
Tougher material to
Not easy to collaspe
build pylon. Steel
alloy
U shape steel alloy
Not too heavy
Large diameter cable
Less resistance
Characteristics of power socket extension for
normal use. (MRSM)
Not using extension
Less resistance, less loss
cord// use shorter
of energy as heat energy
extension wire
One fuse for each
If one fuse blow the other
socket
can still function
Use power surge
Can cut off the supply
protector.
when it is overloaded
Head plug earthed
Flow current leakage to
earth
Suggestion to light up a room. (Pls)
Use fluorescent lamp Consume less energy
Use more efficient
Brighter and prevent
fluorescent lamp.
wastage of energy.
Use fuse
To prevent overheating of
lamp.
Two or more
If one lamp blow out, the
fluorescent lamp is
other can still function.
connected in parallel
Specifications of lamp that is suitable to use as a
reading lamp. (J)
Low power rating
Consume less electrical
energy
Low cost
Save money//cheaper
High efficiency
Produced higher output
power // less energy
wasted
Long lifetime
Last longer
Suitable design for wiring a cabin.
The electric
Allow each electric
appliances are
appliances to be switched
connected in
on and off independently
parallel//diagram
Fit fuse at the live To stop the flow of current
wire in the fuse box by melting when a high
//diagram//
voltage of electric current
Use miniature circuit flows through the circuit //
breakers (mcb’s)
switches itself off very
quickly if the current
exceeds e.g. 15A (for 15A
mcb)
Earth connection to
the metal case of
electrical appliances
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
Use low power lamps
/ install fluorescent
lamp
Use thicker wire
Use insulated wire
Place the power
point at higher place
To save the energy
Reduce resistance
To avoid short circuit
To avoid being touch by
the children
Modification to the desk lamp so it is comfortable to
use
Use a fluorescent
Fluorescent lamp use less
lamp
electrical energy
Use bigger cover
Reduce light directly
with white color
propagate to eye and
reflection and reflector
light and heat energy
Use an adjustable
Height of the lamp can be
stand
adjusted and can be used
anywhere
Connect with earth
Flow the current leakage to
wire
the earth
Use an energy saver
Use same amount of
lamp
energy but light up brighter
Characteristic of connecting wire
Resistance of wire is
To prevent power loss due
low
to heat
Melting point is
Prevent wire from melting
higher
at high temperature
Density of wire is low So it is light weight and
reduce the mass
Rate of rusting is low
Prevent the wire from
rusting and can be use for
longer time
Lower rate of
To prevent lengthening of
expansion
wire
Specification of wire used for heating element
Lower density
The mass is smaller and
light weight
Higher melting point
Will not melt easily at high
temperature
Lower oxidation rate
Can be used for longer
time
Higher resistance
Produce more heat energy
Modification to the circuit to improve safety,
produce the lamps light up with normal brightness
and increases the efficiency of electrical energy
consuming
Attach one fuse to
To break off the circuit
the live wire in the
when large current flow
consumer unit
and produce fire
Use an insulated wire To prevent short circuit
Use thicker wire
To reduce resistance and
improve efficiency.
Attach switch for
To allow each lamp to be
each lamp
switched on and off
independently
Connect the metal
To flow electron (extra) to
fitting lamp to the
earth and avoid electric
earth wire
shock.
Using only 240 V
To ensure the bulbs light
light bulb
up with normal brightness
Connect the bulbs in
Each bulbs will receive
parallel
same voltage
Suitable characteristics of metal to make a water
heater
Smaller surface
The resistance will be
area/diameter
higher
High melting point
Not easy to melt
Low specific heat
The temperature rise
capacity
slowly
Long coiled metal
To increase the resistance.
Characteristics of metal use as a heater. In
electrical kettle.
High resistance
Higher resistance make the
heating better
High melting point
Not easily melt in high
temperature
Low rusting effect
Not easily to rust n safe for
consumer
Low specific heat
Easily 2 become hot
capacity
Characteristics of the current distributor cable in
the car.
Low resistance
A little energy is lost as
heat energy
Low density
Small mass and easy to be
carried/hung
Wire with large
To reduce the resistance
diameter
Low expand rate
Does not contract too
much and becomes too
loose during hot days.
Suggest modifications that can be made to the
electric kettle so that it can boil water faster and
has better safety
Diameter of
Less resistance and
connecting wire is
produce small amount of
bigger
heat. If large current flow
the wire will no be
overheated
Length of connecting Less resistance
wire is shorter
Heating element
Can produced high amount
must have high
of heat energy with smaller
resistivity
current
The kettle is made
Less heat loss to
from good heat
surounding. Water will boil
insulator
faster
Use suitable fuse. If
If higher current flow the
the current flow is
fuse will melt and kettle will
8.3A. Use 13A fuse
no be damaged
cartridge
Essay questions
Problem solving and
decision making
8. ELECTROMAGNETISM
Modification to enable moving coil microphone to
detect sound effectively and generate bigger
current.
Use thin diaphragm
Easy to vibrate.
Use stronger
Not easy to break.
material to built
diaphragm
Use more number of
Increase the rate of change
turns of coil
of magnetic flux.
User thicker wire
To reduce the resistance of
wire.
Use powerful magnet To increase the rate of
to has stronger
change of magnetic flux.
magnetic field
Suggestion to make a hand phone charger (Phg)
Use step down
Able to reduce voltage
transformer
from 240V to 9V
Use a diode
Change ac to dc
Use capacitor
Able to smooth the output
current.
Suggest modification so that the galvanometer can
increase its sensitivity. (J)
Increase the strength Increase the force between
of the magnetic field
current carrying conductor
and the magnetic field.
Using lower stiffness
Smaller opposing force to
of hairspring
stop the turning of the coil
Lighter mass of coil
Smaller inertia, able to
move easily.
Increase the area of
More change to the
the coil
magnetic flux, a bigger
force is produced.
Design of a moving coil ammeter that can function
better(Mk)
Use stronger magnet
Stronger magnetic field/
large rotation
Use curve magnet
Produce radial magnetic
field
Use cylindrical core
To supply uniform
magnetic field strength
Use soft iron core
To concentrate the
magnetic field
Use linear scale
The angle of rotation is
linear and more accurate
Design of the ac generator so that the efficiency of
the generator is higher.
Use soft iron core
To concentrate the
magnetic flux
Increase no of turns
To increase the rate of
of coil
magnetic fluxs cutting
Use bigger/thicker
To reduce resistance of the
wire
wire
Use curve permanent So rate of the rotation and
magnet
magnetic fluxs cutting is
constant
Use powerful
To increase the rate of
permanent magnet
magnetic fluxs change
Suggest modification to ac generator to that can
produce bigger dc current. (Ktn)
Increase the number
Increase the rate of cutting
of turn of coil
the magnetic field
Use stronger magnet
Increase the strength of the
magnetic flux
Use curve magnet
To provide radial magnetic
field
Diameter of wire of
Thicker wire has lower
coil is greater
resistance. Higher current
can flow.
Use copper wire
Lower resistance. More
current flow.
Suitable characteristics of electric bell that can
produces a louder sound
Use bigger hammer
So that the surface area
contact is bigger/produce
more impulsive force
Distance between the The force applied to the
hammer and the
gong is larger
gong is larger
Number of turns of
The strength of the
the coil is larger
magnetism is higher
High curvature of the
The area of air molecule
gong
vibrate is greater.
Modification to be done to enable the electric bell to
ring louder
Increase the number
Produced greater magnetic
of turns of wire
field to produce greater
force.
Increase the
To increase the resultant of
magnitude of
the magnetic field
current/ the number
of cells
Used u-shape soft
Produced stronger
iron core
magnetic field
Use bigger diameter
Will vibrate more air
of the gong
molecules
Use bigger hammer
Produces greater impulsive
force.
Advantage of the National Grid Network
Cost of generation of
electricity is reduced
Electricity supply is
more reliable with
less interruption.
The generation of
electricity at each
station can be
controlled and
regulated
Power station can be
located outside the
city limits.
Because high voltage
reduces the current flow.
Reduces power loss in the
cable.
Because repair and
maintenance work can be
carried at any power
station and at any time.
At peak hours more
generators can be
switched on.
So that air an
environmental pollution
can be reduced.
Suitable characteristics of materials to be used as a
model of power transmission.
Use 12V ac power
Can be change the voltage
supply
with transformer
Use laminated soft
Produced stronger
iron core
magnet// easy to magnetize
and to demagnetized
Use step-up
To increase and to
transformer Np=
decrease the voltage due
1200, Ns=2400 and
to the demand/need.
step-down
transformer with
Np=480 and Ns= 120
Use copper wire
Lower resistance.
Suitable characteristics of cables use as a
transmission cable.
Low resistivity
To reduce heat loss in the
cables
Low density
The cables will be lighter
Low cost
Cost of project will be
lower
Low rate of thermal The cables will not expand
expansion
under hot weather
Modification of the loudspeaker to produce louder
sound.
Increase the number
To increase the magnetic
of turns of coil
field strength/ current
produced
Use larger diameter
Reduce resistance in the
of wire
coil
Cone made from
Easy to vibrate
lighter material
Use stronger magnet
Cone will vibrate stronger
and produced more emf.
Bigger diaphragm
Will vibrate more air to
produce louder
Cone made from
Not easy to break.
tougher material
Suitable characteristics of the hand phone charger.
Connect the output
with a diode
Connect capacitor
Use the primary
turns and secondary
turns with the ratio
2:1
Use soft iron core
Use laminated iron
core
Wound the
secondary coil the
primary coil or
placed very closed to
the primary
coil(along the same
core)
Use wire with low
resistance
Use full wave
rectification circuit
To change a.c. current to
d.c. current
Smoothen the a.c. current
Reduce the current to
become 12V
Can me magnetized n
demagnetized easily and
reduce the energy lost
Increase the resistance to
the flow of eddy current
Prevent leakage of
magnetic flux
Reduce energy lost
To reduce loss of energy
Modification of transformer to become a step-down
transformer with 12V dc output.
Connect the output with
To change a.c. current
a diode
to d.c. current
Connect capacitor
Smoothen the a.c.
current
Use the primary turns
Reduce the current to
and secondary turns
become 12V
with the ratio 2:1
Use soft iron core
Can me magnetized n
demagnetized easily
and reduce the energy
lost
Use laminated iron core
Increase the resistance
to the flow of eddy
current
Wound the secondary
Prevent leakage of
coil the primary coil or
magnetic flux
placed very closed to
the primary coil(along
the same core)
Use wire with low
Reduce energy lost
resistance
Characteristics of cable to be used in the National
Grid Network.
Larger diameter
To reduce the resistance of
wire
Lower density
The cable will be lighter
and can be supported
securely
The rate of
So there is less expansion
expansion is low
and less sagging in the
cable during hot day.
Higher melting point
Cable does not melting in
high temperature.
Problem Involving electricity Transmission
Cost of cable.
• Aluminum cables are
used because the density
is lower (the cables
become lighter), have low
resistance and cheaper.
Loss of power by
• By using thicker
the cables
aluminum cables,
resistance can be
reduced
• By using a high voltage
transmission, the current
in the cables is reduced
and the power dissipated
by the cables is reduced.
Charge leakage
• To prevent charge
between the cables
leakage, the aluminum
and the earth
cables are supported by
high metal tower/pylons.
• The metal support of the
tower is earthed so that it
is safe for the worker or
public.
Suggestions to design a moving coil loudspeaker
that can produce louder sound.
Use radial shape of
The magnetic field strength
magnet
is uniform.
Coil is built
To increase the
surrounding the
effectiveness of the
magnet//Attached to
counter react between the
the magnet
magnetic field.
Used lighter material
Can easily vibrate.
to built diaphragm
Use ac power
Audio signal varies with
the current.
Box made from
Loudspeaker is stronger.
wood/steel
Way to build a industrial lifting electromagnets.
Large number of
Increase the
turns of coil
electromagnetic strength
Use soft iron core
Can be magnetized and
demagnetized easily
Insulated copper
Prevent short circuit
wire
Use higher
To produce a strong
voltage/current
magnetic field
Use thicker wire
To reduce the resistance of
the coil
Design a circuit that can be used to switch on 12V
dc radio
Use step-down
Capable to reducing
transformer
potential difference/voltage
The ratio of no of
Can reduce 240V to 12V
turn of primary coil
to secondary coil
must be 20:1
Using four diodes
Full wave rectification
Using capacitor
To smooth out output
current//produce output of
steady dc
Suggest modification to the dc motor to increase
the efficiency of the motor.
Increase the strength To increase the magnetic
of the magnet
field strength.
Increase the number
To increase the magnitude
of turns of coil
of force
Increase the
To increase the magnitude
magnitude of current
of force/ increase the
strength of the magnetic
field.
Characteristics of dc motor that can be used to lift
heavy object.
Lower density
Coil has smaller
material
mass/lighter
Higher number of
Larger force acting on the
turns of coil
coil. Higher
electromagnetic field
strength
Stronger magnet
Large force acting on the
coil
More number of
Coil rotate smoothly
segment in the
commutator
Essay questions
Problem solving and
decision making
9. ELECTRONICS
Characteristics of circuit with transistor which is
used for fire alarm system.
Negative terminal of
cell is connected to
the emitter/ Positive
terminal of cell is
connected to the
collector of
transistor.
Heat Dependent
Resistor (HDR) is
placed on top while
resistor R is placed
at the bottom.
Resistor Y is placed
at the base of
transistor.
Connects extra
components such as
siren/bell and light.
Use AC current in the
outer circuit to
switch on the siren.
- So that forward biased
occurs
- Current can flows through
the transistor
- So that when there is a
rise in temperature, voltage
across X will be higher.
- Base current will flow.
- To limit the amount of
current that passes
through the transistor./
To protect the transistor
from any damage.
- So that sound or signal is
produced during fire.
- The larger is the AC
current, the louder the is
the siren.
Draws the fire alarm system with electromagnetic
relay at the outer circuit and uses AC
current to switch on the siren
Essay questions
Problem solving and
decision making
10. RADIOACTIVITY
Characteristics of radioisotope to be used to inject
into the blood of a patient to detect the location of a
brain tumor
Shorter half life
Can be active in the body
for shorter period.
Lower ionizing power Causes minimum damage
to the tissues in the body
Emit gamma ray
Can penetrate through the
body and detected by the
GM tube
Characteristics of radioisotope to be use to detect
the level of juice in a bottle
Longer half life
Can be used for longer
time
Beta ray
Can be absorbed and
medium penetrating power
Solid
Easy to handle
Ionizing power is
Not ionize the juice. Safe to
low.
drink.
Suitable characteristics of radioactive to put on the
lighting arrestor. (Pls)
Solid state
Easy to handle
Higher ionizing
Easy for the medium to
power
conduct electricity and
cause the lightning to
divert to the place of higher
ionization.
Longer half life
Can be used for longer
time.
Characteristic of radioisotope to detect the
thickness of paper in a paper industry. (Ktn)
Solid
Easy to handle
Emit beta ray
Medium penetration/ can
be absorbed.
Longer half life
Can be used for longer
time.
Medium penetrating
Less dangerous
power
Characteristic of radioactive use to detect the water
pipe leakage.(J)
Emit gamma
Penetrating power is high
and can penetrate through
pipe and soil.
Shorter half life.
Active in water supply for
shorter time.
Liquid
Can be dissolved in water
easily.
Characteristic of radioisotope use to detect
problem organ/blood circulation (Mk)
Shorter half life
Active in the body for
shorter time
Lower ionizing power Minimize the damage to the
organ.
Gamma ray
Higher penetrating
power/can be detected.
Liquid
Can be dissolved easily
Characteristic of radioisotope use to kill cancerous
cell. (radiotherapy) (Mk)
Long half life
Can be used for longer
time
Lower ionizing power Minimize the damage to the
organ.
Gamma ray
Higher penetrating
power/can be detected.
Solid
Can be handle easily
Explain the suitability of radioactive source to be
use to kill cancer cell
Can produced gamma Higher penetrating power
ray
Longer half-life
Can be used for longer
time
Solid
Easy to handle
Lower ionizing power
Do not cause cell mutation
Suggest how the radioactive material and the
detector should be chosen to be use in the study of
the intake of fertilizer.
Shorter half life – a
This allow time for the
few days.
fertilizer to be absorbed
Use GM tube to
The location of the fertilizer
detect the radiation
can be detected and
analyzed.
Characteristics of paper thickness control device
using radioactive
Half life of
- So that it can be used for
radioactive
a long time./ Does not have
substance is long.
to be changed often.
Radioactive
substances that
release Beta
particles
Solid Radioactive
substances
Use GM tube
GM tube is placed
opposite of the
radioactive source.
Papers are placed at
the centre of GM
tube and radioactive
source.
- Moderate penetrating
force.
- Easy to handle and
manage.
- Can detect Beta particles.
- So that the intensity of
Beta particles can be
detected.
- So that the Beta particles
can penetrate the papers
and detected by GM tube.
Suggestion and explanation how to detect the
presence of blockages in the blood vessel using
radioisotope as a tracer
Use a small amount
Can emit γ, and can
of Natriumpenetrate through the
24//Thaliumpatient’s body
201//Technetium-99
Has short half-life ( a
Not pose any serious
few days)
health risk due to
overexpose to the radiation
Use GM tube as a
Can detect γ ray.
detector
The radioisotope is
Can flow to the entire body
injected to the blood
of the patient.
vessel
Radiation from the
Identify the region that is
radioisotope is
not receiving enough
detected with GM
blood.
tube
-Higher reading means
blockages.
-Lower reading mean the
region is receiving not
enough blood.
Suitable characteristics of radioactive radiation and
detector used to detect the underground water
supply leakage
The radioactive
Can penetrate the soil and
source emit beta
emerge from the ground
particles
Shorter/sufficiently
After the period of two
long half life
days the activity of the
source is weak enough and
not dangerous
Use GM tube as a
Very sensitive, can detect
detector
beta particle and easy to
carry from one place to
another
Use a rate meter
Can give the count rate
directly
Suggestions to modify your school lab with well
equip which can be used to do the research work
for radioactive source safely
Use thick lead box as Radioactive rays cannot
a radioactive source
pass through
container
Radioactive waste is
Prevent the radioactive
packed into stainless waste discharged to the
steel /concrete drum
environment
and buried
underground
Use forceps/robotic
Avoid direct touching
hand
Use siren
Faster warning when
leakage
Characteristics of radioisotopes that are suitable
for use in controlling the population of pest
Use solid
Easy to handle.
radioisotope
Can emit gamma ray
Has higher penetrating
power.
Has longer half-life
Last longer