Table of Contents
SECTION A: MULTIPLE CHOICE QUESTIONS #
1. A block with flat, rectangular faces rests on a table. The block is
now turned so that it rests with its largest side on the table. How has this change affected the force and
the pressure exerted by the block on the table?
Answer: C – force unchanged, pressure decreased
Why this answer is correct:
The force stays the same because the weight of the block does not change when you turn it. Force = weight = mg, and the mass and gravity stay the same.
The pressure decreases because now the block is resting on its largest side, which means more surface area is touching the table. Since pressure = force ÷ area, when area gets bigger and force stays the same, pressure gets smaller.
The force stays the same because the weight of the block does not change when you turn it. Force = weight = mg, and the mass and gravity stay the same.
The pressure decreases because now the block is resting on its largest side, which means more surface area is touching the table. Since pressure = force ÷ area, when area gets bigger and force stays the same, pressure gets smaller.
Remember: Force depends on weight (stays same). Pressure depends on
area touching the surface (changes when you flip object).
2. The diagram shows a stone suspended under the surface of a liquid from
a string. The stone experiences a pressure caused by the liquid. What would increase the pressure on the
stone?
Answer: C – lowering the stone deeper into the liquid
Why this works:
Pressure in liquids increases with depth. The deeper you go, the more liquid is above you pushing down. This is why your ears hurt when you swim to the bottom of a deep pool.
The formula is: pressure = density × gravity × depth
When depth increases, pressure increases.
Pressure in liquids increases with depth. The deeper you go, the more liquid is above you pushing down. This is why your ears hurt when you swim to the bottom of a deep pool.
The formula is: pressure = density × gravity × depth
When depth increases, pressure increases.
Wrong answers explained:
A) Surface area of stone doesn’t matter for liquid pressure
B) Mass of stone doesn’t change liquid pressure on it
D) Lower density liquid would give less pressure
A) Surface area of stone doesn’t matter for liquid pressure
B) Mass of stone doesn’t change liquid pressure on it
D) Lower density liquid would give less pressure
3. The diagram shows a solid block resting on a bench. The dimensions of
the block are shown (40 cm × 80 cm). On which labeled surface should the block rest to produce the
smallest pressure on the bench?
Answer: The largest surface area (80cm × 40cm face)
Logic:
To get the smallest pressure, you need the largest contact area. This spreads the weight over more area.
Think of it like this: stepping on someone’s foot with a flat shoe hurts less than stepping with a high heel shoe, even though your weight is the same.
To get the smallest pressure, you need the largest contact area. This spreads the weight over more area.
Think of it like this: stepping on someone’s foot with a flat shoe hurts less than stepping with a high heel shoe, even though your weight is the same.
Pressure = $\frac{\text{Force}}{\text{Area}}$
Bigger area → Smaller pressure
Smaller area → Bigger pressure
Bigger area → Smaller pressure
Smaller area → Bigger pressure
4. What does a barometer measure?
Answer: C – the pressure of air
What is a barometer:
A barometer measures atmospheric pressure (air pressure). Weather forecasters use barometers because air pressure changes before weather changes.
High pressure usually means good weather.
Low pressure usually means bad weather is coming.
A barometer measures atmospheric pressure (air pressure). Weather forecasters use barometers because air pressure changes before weather changes.
High pressure usually means good weather.
Low pressure usually means bad weather is coming.
5. A man is in contact with the floor. In which of these situations does
he produce the least pressure on the floor?
Answer: B – lying flat on his back
Why lying down gives least pressure:
When lying down, his whole body touches the floor. This gives the biggest contact area.
Standing on one foot gives the smallest area, so highest pressure.
Lying down gives the biggest area, so lowest pressure.
When lying down, his whole body touches the floor. This gives the biggest contact area.
Standing on one foot gives the smallest area, so highest pressure.
Lying down gives the biggest area, so lowest pressure.
Easy way to remember: Lying down spreads your weight over your whole body.
Standing on one foot puts all your weight on just your foot.
SECTION A: ENERGY AND STATES OF MATTER #
6. Which of the following types of energy remains constant during a
change of state?
Answer: A – internal energy
What happens during state changes:
During melting or boiling, the temperature stays the same even though you keep heating. This means the kinetic energy (movement energy) of particles stays the same.
The heat energy goes into breaking bonds between particles, not making them move faster.
During melting or boiling, the temperature stays the same even though you keep heating. This means the kinetic energy (movement energy) of particles stays the same.
The heat energy goes into breaking bonds between particles, not making them move faster.
7. The energy required for a change of state is called
Answer: latent heat
What is latent heat:
Latent heat is the energy needed to change the state of a substance without changing its temperature.
Examples:
• Latent heat of melting – energy to melt ice into water
• Latent heat of vaporization – energy to boil water into steam
Latent heat is the energy needed to change the state of a substance without changing its temperature.
Examples:
• Latent heat of melting – energy to melt ice into water
• Latent heat of vaporization – energy to boil water into steam
8. If a substance expands on melting, increased pressure acting on it
will
Answer: C – decrease its melting point
Why pressure affects melting point:
When you squeeze something that expands when melting, you make it harder for it to expand. This means it needs less heat energy to melt.
Real example: Ice skating works because the pressure from the blade lowers the melting point of ice, creating a thin layer of water to slide on.
When you squeeze something that expands when melting, you make it harder for it to expand. This means it needs less heat energy to melt.
Real example: Ice skating works because the pressure from the blade lowers the melting point of ice, creating a thin layer of water to slide on.
9. The reversed process of melting is
Answer: B – freezing
State changes:
• Melting: solid → liquid
• Freezing: liquid → solid
• Boiling: liquid → gas
• Condensing: gas → liquid
• Sublimation: solid → gas (skips liquid state)
• Melting: solid → liquid
• Freezing: liquid → solid
• Boiling: liquid → gas
• Condensing: gas → liquid
• Sublimation: solid → gas (skips liquid state)
10. The boiling point of water in a pressure cooker is raised by
Answer: D – increasing the pressure outside the cooker
How pressure cookers work:
Higher pressure makes water boil at a higher temperature. This means food cooks faster because the water can get hotter than 100°C before it turns to steam.
At sea level: water boils at 100°C
In pressure cooker: water can boil at 120°C or higher
Higher pressure makes water boil at a higher temperature. This means food cooks faster because the water can get hotter than 100°C before it turns to steam.
At sea level: water boils at 100°C
In pressure cooker: water can boil at 120°C or higher
11. If a sample of water boils at a temperature above 100°C, the water
SECTION A: WAVES #
12. A liquid evaporates at
Answer: D – temperatures above and below its boiling point
Evaporation vs Boiling:
• Evaporation happens at any temperature (even below boiling point)
• Boiling only happens at the boiling point
Water evaporates from puddles even on cold days. But water only boils when heated to 100°C.
• Evaporation happens at any temperature (even below boiling point)
• Boiling only happens at the boiling point
Water evaporates from puddles even on cold days. But water only boils when heated to 100°C.
13. Which of the following liquids is used as the cooling agent in a
household fridge?
Answer: C – freon
How fridges work:
Freon (or similar coolants) evaporates easily. When it evaporates, it takes heat energy away, making things cold. Then it gets compressed back to liquid and the cycle repeats.
Freon (or similar coolants) evaporates easily. When it evaporates, it takes heat energy away, making things cold. Then it gets compressed back to liquid and the cycle repeats.
14. Wave diagram – Which dimensions describe the properties of the wave?
Answer: D – R = amplitude, S = wavelength
Wave parts:
• Amplitude (R) = height from middle to top of wave
• Wavelength (S) = distance from one peak to the next peak
• Speed = how fast the wave travels
Amplitude tells you how strong the wave is.
Wavelength tells you the size of each wave cycle.
• Amplitude (R) = height from middle to top of wave
• Wavelength (S) = distance from one peak to the next peak
• Speed = how fast the wave travels
Amplitude tells you how strong the wave is.
Wavelength tells you the size of each wave cycle.
15. The diagram represents a wave on a rope. Which type of wave is shown
and which labelled arrow shows the wavelength?
Answer: D – transverse wave, wavelength shown by arrow X
Types of waves:
• Transverse waves: particles move up and down, wave travels sideways (like waves on water or rope)
• Longitudinal waves: particles move back and forth in same direction as wave (like sound waves)
Wavelength is always measured from one peak to the next peak, or from one trough to the next trough.
• Transverse waves: particles move up and down, wave travels sideways (like waves on water or rope)
• Longitudinal waves: particles move back and forth in same direction as wave (like sound waves)
Wavelength is always measured from one peak to the next peak, or from one trough to the next trough.
16. Which diagram shows the reflection of a ray of light at a plane
mirror?
Answer: The diagram where angle of incidence = angle of reflection (measured
from the normal)
Law of reflection:
The angle going into the mirror equals the angle coming out of the mirror.
Both angles are measured from the normal (imaginary line perpendicular to the mirror surface).
The angle going into the mirror equals the angle coming out of the mirror.
Both angles are measured from the normal (imaginary line perpendicular to the mirror surface).
17. Which of these properties is the same for all electromagnetic waves?
Answer: C – speed in free space
Electromagnetic waves:
All electromagnetic waves travel at the speed of light in space (300,000,000 m/s).
This includes: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
They have different frequencies and wavelengths, but same speed in space.
All electromagnetic waves travel at the speed of light in space (300,000,000 m/s).
This includes: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
They have different frequencies and wavelengths, but same speed in space.
18. Which of these could be the frequency of an ultrasound wave?
Answer: D – 45000Hz
Ultrasound:
Ultrasound waves have frequencies above 20,000 Hz (20 kHz). Humans can only hear sounds from about 20 Hz to 20,000 Hz.
Medical ultrasound usually uses frequencies of millions of Hz, but 45,000 Hz is the only option above human hearing range.
Ultrasound waves have frequencies above 20,000 Hz (20 kHz). Humans can only hear sounds from about 20 Hz to 20,000 Hz.
Medical ultrasound usually uses frequencies of millions of Hz, but 45,000 Hz is the only option above human hearing range.
19. The diagram shows a water wave. The amplitude of the wave is
Answer: B – 2 cm
Reading wave graphs:
Amplitude is the distance from the middle line to the highest point (or lowest point).
If the wave goes from +2 cm to -2 cm, the amplitude is 2 cm (not 4 cm).
Amplitude is the distance from the middle line to the highest point (or lowest point).
If the wave goes from +2 cm to -2 cm, the amplitude is 2 cm (not 4 cm).
20. A scanner uses one type of wave to check for broken bones. The type
of wave emitted by the scanner is
Answer: D – X-rays
Medical waves:
• X-rays can pass through soft tissue but not through bones, so they show broken bones
• Ultrasound is used for seeing babies during pregnancy
• MRI uses radio waves and magnetic fields
• Infrared shows heat
• X-rays can pass through soft tissue but not through bones, so they show broken bones
• Ultrasound is used for seeing babies during pregnancy
• MRI uses radio waves and magnetic fields
• Infrared shows heat
21. Which statement about sound waves is correct?
Answer: C – sound waves are longitudinal
Sound wave facts:
• Sound waves are longitudinal (particles vibrate back and forth)
• Sound waves can be reflected (that’s how echoes work)
• Sound waves are not electromagnetic (they need matter to travel through)
• Sound waves are not transverse
• Sound waves are longitudinal (particles vibrate back and forth)
• Sound waves can be reflected (that’s how echoes work)
• Sound waves are not electromagnetic (they need matter to travel through)
• Sound waves are not transverse
22. Which part of the electromagnetic spectrum has longer wavelengths
than microwaves?
Answer: B – radio waves
Electromagnetic spectrum order (longest to shortest
wavelength):
Radio waves → Microwaves → Infrared → Visible light → Ultraviolet → X-rays → Gamma rays
Radio waves have the longest wavelengths and lowest frequencies.
Gamma rays have the shortest wavelengths and highest frequencies.
Radio waves → Microwaves → Infrared → Visible light → Ultraviolet → X-rays → Gamma rays
Radio waves have the longest wavelengths and lowest frequencies.
Gamma rays have the shortest wavelengths and highest frequencies.
23. Which of these statements is correct about microwaves and radio
waves?
Answer: C – Microwaves and radio waves travel at the same speed in a vacuum
Speed of electromagnetic waves:
All electromagnetic waves travel at the same speed in a vacuum (space) – the speed of light.
They can travel at different speeds in materials like glass or water, but in empty space they all go at 300,000,000 m/s.
All electromagnetic waves travel at the same speed in a vacuum (space) – the speed of light.
They can travel at different speeds in materials like glass or water, but in empty space they all go at 300,000,000 m/s.
24. Which electromagnetic radiation has a frequency greater than
ultraviolet?
Answer: B – gamma rays
Frequency order (lowest to highest):
Radio → Microwaves → Infrared → Visible → Ultraviolet → X-rays → Gamma rays
Higher frequency = more energy = more dangerous
Gamma rays have the highest frequency and are very dangerous.
Radio → Microwaves → Infrared → Visible → Ultraviolet → X-rays → Gamma rays
Higher frequency = more energy = more dangerous
Gamma rays have the highest frequency and are very dangerous.
25. Water in a beaker evaporates when left on a bench for a period of
time. Which factors all affect the rate of evaporation of water?
Answer: A – wind speed, surface area, temperature
What makes evaporation faster:
• Higher temperature – gives water molecules more energy to escape
• More surface area – more water surface exposed to air
• Wind – blows away water vapor so more can evaporate
Volume doesn’t affect the rate, only the total time it takes to evaporate all the water.
• Higher temperature – gives water molecules more energy to escape
• More surface area – more water surface exposed to air
• Wind – blows away water vapor so more can evaporate
Volume doesn’t affect the rate, only the total time it takes to evaporate all the water.
SECTION B: STRUCTURED QUESTIONS #
1(a). Name the following processes:
(i) A solid changes into a liquid: Melting
(ii) A liquid changes into a solid: Freezing
(iii) A liquid changes into a gas at a particular temperature:
Boiling
(iv) A liquid changes into a gas at ordinary room temperature:
Evaporation
(v) A gas changes into a liquid: Condensation
State changes summary:
Think of it like this: solid ↔ liquid ↔ gas
• Going right needs heat energy
• Going left releases heat energy
Sublimation is when solid goes directly to gas (like dry ice).
Think of it like this: solid ↔ liquid ↔ gas
• Going right needs heat energy
• Going left releases heat energy
Sublimation is when solid goes directly to gas (like dry ice).
1(b). What would you expect the boiling point of water to be if its
freezing point is less than zero degrees celsius?
Less than 100°C
Why this makes sense:
If water freezes at a lower temperature than normal, it means the water has impurities or is under different conditions. This would also make it boil at a lower temperature than normal.
Pure water freezes at 0°C and boils at 100°C at standard pressure.
If water freezes at a lower temperature than normal, it means the water has impurities or is under different conditions. This would also make it boil at a lower temperature than normal.
Pure water freezes at 0°C and boils at 100°C at standard pressure.
1(c). Describe how the melting point of water is affected by:
(i) Presence of sugar: Decreases the melting point
(ii) Altitude: The melting point stays almost the same
Explanation:
• Sugar (or any dissolved substance) makes ice melt at a lower temperature. This is why we put salt on roads in winter.
• Altitude mainly affects boiling point, not melting point much. Higher altitude = lower air pressure = lower boiling point.
• Sugar (or any dissolved substance) makes ice melt at a lower temperature. This is why we put salt on roads in winter.
• Altitude mainly affects boiling point, not melting point much. Higher altitude = lower air pressure = lower boiling point.
1(d). Explain why we feel cooler when wind blows over us.
When wind blows, it helps sweat evaporate from our skin faster. Evaporation
needs heat energy, so it takes heat from our body and makes us feel cooler.
The cooling process:
1. Our body makes sweat (water)
2. Wind helps this water evaporate
3. Evaporation takes heat energy from our skin
4. Less heat on our skin = we feel cooler
This is why fans make you feel cooler even though they don’t actually cool the air.
1. Our body makes sweat (water)
2. Wind helps this water evaporate
3. Evaporation takes heat energy from our skin
4. Less heat on our skin = we feel cooler
This is why fans make you feel cooler even though they don’t actually cool the air.
1(e). Using your knowledge of the kinetic theory, explain why evaporation
produces a cooling effect.
In any liquid, molecules are moving at different speeds. The fastest-moving
molecules have enough energy to escape from the surface (evaporate). When these high-energy molecules
leave, the average energy of the remaining molecules decreases, so the liquid becomes cooler.
Think of it this way:
Imagine a class where the most energetic students leave. The remaining students are, on average, less energetic.
Same with molecules – when the most energetic ones evaporate, the remaining liquid has less average energy = lower temperature.
Imagine a class where the most energetic students leave. The remaining students are, on average, less energetic.
Same with molecules – when the most energetic ones evaporate, the remaining liquid has less average energy = lower temperature.
2(a). Explain why the ray of light is refracted towards the normal.
Light slows down when it enters the glass block because glass is denser than
air. When light slows down, it bends towards the normal.
Refraction rule:
• Light going from less dense to more dense material: bends TOWARDS normal
• Light going from more dense to less dense material: bends AWAY FROM normal
Air is less dense than glass, so light bends towards the normal when entering glass.
• Light going from less dense to more dense material: bends TOWARDS normal
• Light going from more dense to less dense material: bends AWAY FROM normal
Air is less dense than glass, so light bends towards the normal when entering glass.
3. Draw a line linking each type of electromagnetic wave with its use.
| Electromagnetic Wave | Use |
|---|---|
| Gamma rays | Treating cancer patients with medical tracers |
| Microwaves | Heating food |
| X-rays | Imaging broken bones |
Why these waves work for these jobs:
• Gamma rays are very high energy – can kill cancer cells
• Microwaves make water molecules vibrate – heats food from inside
• X-rays pass through soft tissue but not bone – shows bone structure
• Gamma rays are very high energy – can kill cancer cells
• Microwaves make water molecules vibrate – heats food from inside
• X-rays pass through soft tissue but not bone – shows bone structure
4(a). Draw arrows on the diagram to show the directions in which the
teacher moves his hand to demonstrate longitudinal waves.
[INSERT DIAGRAM: Spring diagram for adding arrows showing hand movement direction]
Arrows should point back and forth horizontally along the spring (same direction
as wave travel)
Longitudinal waves:
The hand moves back and forth in the same direction that the wave travels. This creates compressions (squeezed parts) and rarefactions (stretched parts) in the spring.
The hand moves back and forth in the same direction that the wave travels. This creates compressions (squeezed parts) and rarefactions (stretched parts) in the spring.
4(a)(ii). Give an example of a longitudinal wave.
Sound waves
Examples of waves:
• Longitudinal: sound waves, waves in springs when pushed/pulled
• Transverse: light waves, water waves, waves on strings when moved up/down
• Longitudinal: sound waves, waves in springs when pushed/pulled
• Transverse: light waves, water waves, waves on strings when moved up/down
5. Complete the table by giving one radiation from the chart for each
use.
[INSERT DIAGRAM: Electromagnetic spectrum chart showing radio, microwave, infrared, visible,
ultraviolet, X-ray, gamma ray]
| Use | Type of Radiation |
|---|---|
| Cooking | Microwave |
| Treating cancer | Gamma ray |
| Identifying broken bones | X-ray |
Remember for exams: Each type of electromagnetic radiation has
specific uses based on their properties and energy levels. High energy waves (gamma, X-ray) are used in
medicine. Medium energy waves (microwave, infrared) are used for heating.
Study Tips for Wave Questions:
1. Remember the electromagnetic spectrum order
2. Know that all EM waves travel at speed of light in space
3. Higher frequency = higher energy = more dangerous
4. Sound waves are NOT electromagnetic waves
5. For refraction: denser material = light slows down and bends toward normal
1. Remember the electromagnetic spectrum order
2. Know that all EM waves travel at speed of light in space
3. Higher frequency = higher energy = more dangerous
4. Sound waves are NOT electromagnetic waves
5. For refraction: denser material = light slows down and bends toward normal
