An original Thinka practice paper modelled on the structure and difficulty of the Nov 2024 (V3) Cambridge IGCSE Physics (0625) paper. Not affiliated with or reproduced from Cambridge.
Extended Theory Paper 4 (必答 結構題)
Answer all questions in the spaces provided. Show all working and use appropriate units.
40 題目 · 40 分
題目 1 · 選擇題
1 分
A toy car travels a distance of 120 m in 20 s, and then remains stationary for 10 s. What is the average speed of the toy car over the entire 30 s?
A.3.0 m/s
B.4.0 m/s
C.6.0 m/s
D.12 m/s
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解題
The average speed is calculated by dividing the total distance travelled by the total time taken. The total distance is 120 m. The total time is 20 s + 10 s = 30 s. Average speed = \(120 \text{ m} / 30 \text{ s} = 4.0 \text{ m/s}\).
評分準則
1 mark for dividing total distance (120 m) by total time (30 s) to obtain 4.0 m/s.
題目 2 · 選擇題
1 分
An astronaut has a mass of 80 kg on Earth. The gravitational field strength on Earth is 9.8 N/kg and on the Moon is 1.6 N/kg. What are the mass and the weight of the astronaut on the Moon?
A.mass = 13 kg, weight = 128 N
B.mass = 80 kg, weight = 128 N
C.mass = 80 kg, weight = 784 N
D.mass = 13 kg, weight = 784 N
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解題
Mass is a property of the object and does not change when the gravitational field strength changes, so the mass on the Moon is still 80 kg. Weight is calculated using \(W = m \times g\). On the Moon, \(W = 80 \text{ kg} \times 1.6 \text{ N/kg} = 128 \text{ N}\).
評分準則
1 mark for identifying mass remains 80 kg and calculating weight as 128 N.
題目 3 · 選擇題
1 分
A block of weight 240 N has a rectangular base of dimensions 0.40 m by 0.50 m. It rests on flat ground. What is the pressure exerted by the block on the ground?
A.48 Pa
B.120 Pa
C.600 Pa
D.1200 Pa
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解題
First, calculate the area of the base: \(A = 0.40 \text{ m} \times 0.50 \text{ m} = 0.20 \text{ m}^2\). Then, use the pressure formula: \(P = \frac{F}{A} = \frac{240 \text{ N}}{0.20 \text{ m}^2} = 1200 \text{ Pa}\).
評分準則
1 mark for calculating the correct contact area (0.20 m²) and using pressure = force / area to obtain 1200 Pa.
題目 4 · 選擇題
1 分
Which energy resource is non-renewable?
A.Coal
B.Geothermal
C.Wind
D.Solar
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解題
Coal is a fossil fuel. Fossil fuels are finite resources that cannot be easily replaced once used, making them non-renewable. Geothermal, wind, and solar energy are naturally replenished and are renewable.
評分準則
1 mark for selecting the correct non-renewable energy source (Coal).
題目 5 · 選擇題
1 分
The temperature of a gas in a container is increased from 20 °C to 50 °C. What is this change in temperature expressed in kelvin (K)?
A.30 K
B.243 K
C.273 K
D.303 K
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解題
A change in temperature of 1 °C is equal to a change in temperature of 1 K. Therefore, the temperature change is \(50 °C - 20 °C = 30 °C\), which corresponds to exactly 30 K.
評分準則
1 mark for identifying that a change on the Celsius scale is numerically identical to a change on the Kelvin scale (30 K).
題目 6 · 選擇題
1 分
A gas is stored in a sealed container of fixed volume. The gas is heated. What happens to the gas particles?
A.They expand and become larger.
B.They collide with the walls less frequently.
C.Their average kinetic energy increases.
D.Their average distance from each other increases.
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解題
Heating the gas increases its temperature, which means the average kinetic energy of the gas particles increases. Since the volume is fixed, the particles do not spread further apart on average, nor do the individual particles expand.
評分準則
1 mark for recognizing that heating a gas increases the average kinetic energy of its particles.
題目 7 · 選擇題
1 分
A wave has a frequency of 10 Hz and a wavelength of 2.0 m. What is the speed of the wave?
A.0.20 m/s
B.5.0 m/s
C.20 m/s
D.40 m/s
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解題
Using the wave equation \(v = f \lambda\), where \(f = 10 \text{ Hz}\) and \(\lambda = 2.0 \text{ m}\), the wave speed is \(v = 10 \times 2.0 = 20 \text{ m/s}\).
評分準則
1 mark for using the wave formula correctly to calculate 20 m/s.
題目 8 · 選擇題
1 分
A light bulb is connected to a 12 V battery. The current in the bulb is 2.0 A. How much electrical energy is transferred by the bulb in 5.0 minutes?
A.24 J
B.120 J
C.1440 J
D.7200 J
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解題
First, convert time into seconds: \(t = 5.0 \text{ minutes} = 5.0 \times 60 = 300 \text{ s}\). Use the formula for electrical energy: \(E = V \times I \times t = 12 \text{ V} \times 2.0 \text{ A} \times 300 \text{ s} = 7200 \text{ J}\).
評分準則
1 mark for converting minutes to seconds and applying the electrical energy formula to find 7200 J.
題目 9 · 選擇題
1 分
A student has a stack of 200 identical sheets of paper. The total thickness of the stack is measured using a ruler as \(18.0\text{ mm}\). What is the average thickness of one sheet of paper?
A.\(0.0090\text{ mm}\)
B.\(0.090\text{ mm}\)
C.\(0.90\text{ mm}\)
D.\(9.0\text{ mm}\)
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解題
To find the average thickness of one sheet, divide the total thickness of the stack by the number of sheets:
\(\text{Thickness of one sheet} = \frac{18.0\text{ mm}}{200} = 0.090\text{ mm}\).
評分準則
1 mark for the correct option B.
題目 10 · 選擇題
1 分
A cyclist travels at a constant speed of \(6.0\text{ m/s}\) for \(2.0\text{ minutes}\). What is the distance travelled by the cyclist?
A.\(12\text{ m}\)
B.\(24\text{ m}\)
C.\(360\text{ m}\)
D.\(720\text{ m}\)
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解題
First, convert the time from minutes to seconds: \(t = 2.0\text{ minutes} = 2.0 \times 60\text{ s} = 120\text{ s}\).
An astronaut has a mass of \(80\text{ kg}\) on Earth. The gravitational field strength on the Moon is \(1.6\text{ N/kg}\). What are the mass and the weight of the astronaut on the Moon?
1. Mass is a measure of the amount of matter in an object and does not change with location. Therefore, the mass on the Moon is still \(80\text{ kg}\). 2. Weight depends on the gravitational field strength: \(W = m \times g\). \(W = 80\text{ kg} \times 1.6\text{ N/kg} = 128\text{ N}\).
評分準則
1 mark for the correct option A.
題目 12 · 選擇題
1 分
A student determines the density of an irregular stone. She measures its mass as \(120\text{ g}\). She then lowers the stone into a measuring cylinder containing water. The volume of water before adding the stone is \(50\text{ cm}^3\), and after adding the stone it is \(80\text{ cm}^3\). What is the density of the stone?
A.\(1.5\text{ g/cm}^3\)
B.\(2.4\text{ g/cm}^3\)
C.\(4.0\text{ g/cm}^3\)
D.\(6.0\text{ g/cm}^3\)
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解題
1. Find the volume of the stone from the displacement of water: \(V = 80\text{ cm}^3 - 50\text{ cm}^3 = 30\text{ cm}^3\).
2. Calculate the density using \(\rho = \frac{m}{V}\): \(\rho = \frac{120\text{ g}}{30\text{ cm}^3} = 4.0\text{ g/cm}^3\).
評分準則
1 mark for the correct option C.
題目 13 · 選擇題
1 分
A toy car is acted upon by two forces along a horizontal line. A forward thrust of \(12\text{ N}\) acts to the right, and a resistive drag of \(4\text{ N}\) acts to the left. What is the size and direction of the resultant force on the car?
A.\(8\text{ N}\) to the left
B.\(8\text{ N}\) to the right
C.\(16\text{ N}\) to the left
D.\(16\text{ N}\) to the right
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解題
The forces act in opposite directions, so we subtract them to find the resultant force: \(12\text{ N} - 4\text{ N} = 8\text{ N}\). Because the larger force acts to the right, the resultant force acts to the right.
評分準則
1 mark for the correct option B.
題目 14 · 選擇題
1 分
A wooden block of weight \(30\text{ N}\) has a flat rectangular base with dimensions \(0.15\text{ m}\) by \(0.20\text{ m}\). The block rests on a table. What is the pressure exerted by the block on the table?
A.\(30\text{ Pa}\)
B.\(150\text{ Pa}\)
C.\(200\text{ Pa}\)
D.\(1000\text{ Pa}\)
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解題
1. Calculate the contact area of the base: \(A = 0.15\text{ m} \times 0.20\text{ m} = 0.03\text{ m}^2\).
2. Use the pressure formula \(P = \frac{F}{A}\): \(P = \frac{30\text{ N}}{0.03\text{ m}^2} = 1000\text{ Pa}\) (or \(1000\text{ N/m}^2\)).
評分準則
1 mark for the correct option D.
題目 15 · 選擇題
1 分
The temperature of a liquid increases by \(20\text{ }^{\circ}\text{C}\). What is this temperature increase expressed in kelvin (K)?
A.\(20\text{ K}\)
B.\(253\text{ K}\)
C.\(293\text{ K}\)
D.\(313\text{ K}\)
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解題
A temperature change of \(1\text{ }^{\circ}\text{C}\) is exactly equal to a temperature change of \(1\text{ K}\). Therefore, a temperature increase of \(20\text{ }^{\circ}\text{C}\) is equivalent to an increase of \(20\text{ K}\).
評分準則
1 mark for the correct option A.
題目 16 · 選擇題
1 分
A sound wave becomes louder and has a higher pitch. What happens to the amplitude and the frequency of the sound wave?
A.amplitude decreases, frequency decreases
B.amplitude decreases, frequency increases
C.amplitude increases, frequency decreases
D.amplitude increases, frequency increases
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解題
1. Loudness is directly related to the amplitude of a sound wave. A louder sound means a larger amplitude. 2. Pitch is directly related to the frequency of a sound wave. A higher pitch means a higher frequency.
評分準則
1 mark for the correct option D.
題目 17 · 選擇題
1 分
A student uses a measuring cylinder to find the volume of a metal coin. The initial volume of water in the cylinder is \(50\text{ cm}^3\). The student lowers 5 identical coins into the cylinder. The water level rises to \(65\text{ cm}^3\). What is the volume of one coin?
A.\(3.0\text{ cm}^3\)
B.\(13.0\text{ cm}^3\)
C.\(15.0\text{ cm}^3\)
D.\(23.0\text{ cm}^3\)
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解題
First, calculate the total volume of all 5 coins by finding the difference in the water level: \(65\text{ cm}^3 - 50\text{ cm}^3 = 15\text{ cm}^3\). Next, divide this volume by the number of coins (5) to find the volume of a single coin: \(\frac{15\text{ cm}^3}{5} = 3.0\text{ cm}^3\).
評分準則
A is the correct answer. 1 mark for the correct calculation: (65 - 50) / 5 = 3.0
題目 18 · 選擇題
1 分
A runner completes a \(400\text{ m}\) race in \(80\text{ s}\). What is the runner's average speed?
A.\(0.20\text{ m/s}\)
B.\(5.0\text{ m/s}\)
C.\(320\text{ m/s}\)
D.\(32\,000\text{ m/s}\)
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解題
The formula for average speed is: \(\text{average speed} = \frac{\text{total distance}}{\text{total time}}\). Substituting the given values: \(\text{average speed} = \frac{400\text{ m}}{80\text{ s}} = 5.0\text{ m/s}\).
評分準則
B is the correct answer. 1 mark for the correct calculation: 400 / 80 = 5.0
題目 19 · 選擇題
1 分
An astronaut has a mass of \(75\text{ kg}\) on Earth. The gravitational field strength on the Moon is \(1.6\text{ N/kg}\). What is the mass and the weight of the astronaut on the Moon?
Mass is a measure of the quantity of matter in an object and remains constant regardless of location, so the mass on the Moon is \(75\text{ kg}\). Weight depends on gravity and is calculated using \(W = m \times g\). Therefore, \(W = 75\text{ kg} \times 1.6\text{ N/kg} = 120\text{ N}\).
評分準則
B is the correct answer. 1 mark for identifying that mass is constant (75 kg) and weight is 120 N (75 * 1.6).
題目 20 · 選擇題
1 分
The mass of a wooden block is \(240\text{ g}\) and its volume is \(300\text{ cm}^3\). What is the density of the wood?
A.\(0.80\text{ g/cm}^3\)
B.\(1.25\text{ g/cm}^3\)
C.\(72.0\text{ g/cm}^3\)
D.\(72\,000\text{ g/cm}^3\)
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解題
The formula for density is \(\rho = \frac{m}{V}\). Substituting the values: \(\rho = \frac{240\text{ g}}{300\text{ cm}^3} = 0.80\text{ g/cm}^3\).
評分準則
A is the correct answer. 1 mark for the correct calculation: 240 / 300 = 0.80
題目 21 · 選擇題
1 分
The temperature of a gas in a sealed container is increased. The volume of the container does not change. What happens to the pressure of the gas and the average speed of the gas particles?
A.gas pressure decreases, average speed of particles decreases
B.gas pressure decreases, average speed of particles increases
C.gas pressure increases, average speed of particles decreases
D.gas pressure increases, average speed of particles increases
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解題
As temperature increases, the kinetic energy of the gas particles increases, so their average speed increases. Because they are moving faster, they collide more frequently and harder with the container walls, which increases the pressure.
評分準則
D is the correct answer. 1 mark for identifying that both gas pressure and average speed of particles increase.
題目 22 · 選擇題
1 分
Which process is the main method of thermal energy transfer through a metal bar when one end is heated?
A.conduction
B.convection
C.radiation
D.evaporation
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解題
Conduction is the main method of thermal energy transfer in solids, particularly metals, where vibrating particles pass kinetic energy to neighboring particles, assisted by free electrons.
評分準則
A is the correct answer. 1 mark for selecting conduction.
題目 23 · 選擇題
1 分
A ray of light is incident on a plane mirror. The angle of incidence is \(35^\circ\). What is the angle between the incident ray and the reflected ray?
A.\(35^\circ\)
B.\(55^\circ\)
C.\(70^\circ\)
D.\(110^\circ\)
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解題
By the law of reflection, the angle of reflection is equal to the angle of incidence, so the angle of reflection is also \(35^\circ\). The total angle between the incident and reflected rays is the sum of these two angles: \(35^\circ + 35^\circ = 70^\circ\).
評分準則
C is the correct answer. 1 mark for calculating the total angle: 35 + 35 = 70
題目 24 · 選擇題
1 分
A radioactive source has a half-life of \(20\text{ minutes}\). The initial count rate is \(800\text{ counts per minute}\). What will be the count rate after \(1\text{ hour}\)?
A.\(100\text{ counts per minute}\)
B.\(200\text{ counts per minute}\)
C.\(267\text{ counts per minute}\)
D.\(400\text{ counts per minute}\)
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解題
First, calculate the number of half-lives that occur in \(1\text{ hour}\) (which is \(60\text{ minutes}\)): \(\frac{60}{20} = 3\text{ half-lives}\). Halve the count rate 3 times: \(800 \rightarrow 400 \rightarrow 200 \rightarrow 100\text{ counts per minute}\).
評分準則
A is the correct answer. 1 mark for the correct calculation: 800 / (2^3) = 100
題目 25 · 選擇題
1 分
A student wants to find the volume of a small, irregularly shaped piece of metal. She pours some water into a measuring cylinder and records the initial volume. She then lowers the piece of metal into the measuring cylinder and records the new volume.
Initially, the water level is at \(30\text{ cm}^3\). After lowering the metal piece, the water level rises to \(42\text{ cm}^3\).
What is the volume of the piece of metal?
A.\(12\text{ cm}^3\)
B.\(30\text{ cm}^3\)
C.\(42\text{ cm}^3\)
D.\(72\text{ cm}^3\)
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解題
The volume of the piece of metal is found by calculating the difference between the final water level and the initial water level:
A wooden crate is pushed across a rough horizontal floor with a forward force of \(50\text{ N}\). A frictional force of \(15\text{ N}\) acts on the crate in the opposite direction.
What is the size of the resultant horizontal force acting on the crate?
A.\(15\text{ N}\)
B.\(35\text{ N}\)
C.\(50\text{ N}\)
D.\(65\text{ N}\)
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解題
The resultant force is calculated by subtracting the opposing frictional force from the forward force:
Award 1 mark for the correct application of the pressure formula.
題目 30 · 選擇題
1 分
Which statement correctly describes the arrangement and motion of particles in a liquid?
A.The particles are far apart and move randomly at high speeds.
B.The particles are tightly packed in a regular lattice and only vibrate about fixed positions.
C.The particles are close together but free to move past one another in a random manner.
D.The particles are far apart and fixed in a rigid structure.
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解題
In liquids, the particles are close together but are not fixed in a rigid structure, allowing them to slide past one another and move in a random manner.
評分準則
Award 1 mark for selecting the correct descriptions of both arrangement and motion of liquid particles.
題目 31 · 選擇題
1 分
A hot metal rod is placed inside a vacuum chamber.
By which process or processes can thermal energy transfer from the hot metal rod to the walls of the chamber?
A.conduction and convection only
B.conduction only
C.convection only
D.radiation only
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解題
Conduction and convection require a physical medium containing particles to transfer heat. Because a vacuum is empty space, only radiation (which travels as electromagnetic waves) can transfer thermal energy through it.
評分準則
Award 1 mark for identifying radiation as the sole method of heat transfer through a vacuum.
題目 32 · 選擇題
1 分
An engineer adjusts an audio generator to change a sound wave. She increases the frequency of the sound wave while keeping its amplitude constant.
How do the pitch and the loudness of the sound change?
A.The pitch increases and the loudness increases.
B.The pitch increases and the loudness stays the same.
C.The pitch stays the same and the loudness increases.
D.The pitch decreases and the loudness stays the same.
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解題
Frequency determines the pitch of a sound wave (higher frequency leads to a higher pitch). Amplitude determines the loudness of a sound wave (since amplitude is constant, loudness remains the same).
評分準則
Award 1 mark for correctly matching frequency change to pitch and constant amplitude to constant loudness.
題目 33 · 選擇題
1 分
A student has a pack of 500 identical sheets of paper. The total thickness of the pack is measured using a ruler and is found to be 4.5 cm.
What is the average thickness of a single sheet of paper?
A.0.009 mm
B.0.09 mm
C.0.9 mm
D.9.0 mm
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解題
First, convert the total thickness from centimetres to millimetres: $$4.5\text{ cm} = 45\text{ mm}$$
Next, divide the total thickness by the number of sheets of paper to find the thickness of one sheet: $$\text{thickness} = \frac{45\text{ mm}}{500} = 0.09\text{ mm}$$
Therefore, the correct option is B.
評分準則
Award 1 mark for the correct option B.
題目 34 · 選擇題
1 分
A car travels along a straight road. It travels a distance of 240 m in a time of 15 s, and then remains stationary for 5.0 s.
What is the average speed of the car for the entire 20 s journey?
A.12 m/s
B.16 m/s
C.48 m/s
D.80 m/s
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解題
To calculate the average speed, use the formula: $$\text{average speed} = \frac{\text{total distance}}{\text{total time}}$$
Here, the total distance is $240\text{ m}$, and the total time is: $$15\text{ s} + 5.0\text{ s} = 20\text{ s}$$
Calculate the average speed: $$\text{average speed} = \frac{240\text{ m}}{20\text{ s}} = 12\text{ m/s}$$
Therefore, the correct option is A.
評分準則
Award 1 mark for the correct option A.
題目 35 · 選擇題
1 分
An astronaut has a mass of 80 kg on the Earth, where the gravitational field strength $g$ is $9.8\text{ N/kg}$.
The astronaut travels to the Moon, where the gravitational field strength is $1.6\text{ N/kg}$.
Which row correctly identifies the mass and weight of the astronaut on the Moon?
A.mass = 13 kg, weight = 128 N
B.mass = 80 kg, weight = 128 N
C.mass = 80 kg, weight = 784 N
D.mass = 490 kg, weight = 784 N
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解題
Mass is a measure of the quantity of matter in an object and does not change with location. Therefore, the astronaut's mass on the Moon is still $80\text{ kg}$.
Weight is the gravitational force acting on an object, calculated using: $$\text{weight} = \text{mass} \times g$$ $$\text{weight} = 80\text{ kg} \times 1.6\text{ N/kg} = 128\text{ N}$$
Therefore, the correct option is B.
評分準則
Award 1 mark for the correct option B.
題目 36 · 選擇題
1 分
During the process of evaporation, liquid water turns into water vapour at room temperature.
Which statement about this process is correct?
A.Only the least energetic water molecules escape, leaving the remaining liquid warmer.
B.Only the least energetic water molecules escape, leaving the remaining liquid cooler.
C.Only the most energetic water molecules escape, leaving the remaining liquid warmer.
D.Only the most energetic water molecules escape, leaving the remaining liquid cooler.
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解題
Evaporation occurs when the most energetic molecules at the surface of a liquid gain enough energy to escape the attractive forces of the surrounding molecules and leave the liquid. Because the molecules with the highest kinetic energy escape, the average kinetic energy of the remaining molecules decreases, which results in the remaining liquid becoming cooler.
Therefore, the correct option is D.
評分準則
Award 1 mark for the correct option D.
題目 37 · 選擇題
1 分
A metal spoon is placed in a hot bowl of soup. Soon, the handle of the spoon becomes hot.
By which process is thermal energy mainly transferred through the metal spoon?
A.conduction
B.convection
C.evaporation
D.radiation
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解題
Thermal energy is transferred through solids, especially metals, primarily by conduction. This occurs because the particles and free electrons in the hot end vibrate and move more rapidly, colliding with neighbouring particles and transferring kinetic energy along the spoon.
Therefore, the correct option is A.
評分準則
Award 1 mark for the correct option A.
題目 38 · 選擇題
1 分
Which material can be easily magnetized to form a temporary magnet, but loses its magnetism quickly when the magnetizing field is removed?
A.copper
B.plastic
C.soft iron
D.steel
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解題
Soft iron is a magnetically 'soft' material. It is easily magnetized and easily demagnetized, making it suitable for temporary magnets (like electromagnets). Steel is magnetically 'hard' and retains its magnetism, making it suitable for permanent magnets. Copper and plastic are non-magnetic.
Therefore, the correct option is C.
評分準則
Award 1 mark for the correct option C.
題目 39 · 選擇題
1 分
A small electric motor is switched on for 2.0 minutes. During this time, a current of 0.50 A passes through the motor.
How much electric charge flows through the motor in this time?
A.1.0 C
B.4.0 C
C.60 C
D.240 C
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解題
First, convert the time from minutes to seconds: $$t = 2.0\text{ minutes} = 2.0 \times 60\text{ s} = 120\text{ s}$$
Use the equation relating charge ($Q$), current ($I$), and time ($t$): $$Q = I \times t$$ $$Q = 0.50\text{ A} \times 120\text{ s} = 60\text{ C}$$
Therefore, the correct option is C.
評分準則
Award 1 mark for the correct option C.
題目 40 · 選擇題
1 分
A radioactive isotope has a half-life of 6.0 hours. A sample of this isotope has an initial count rate of 800 counts per minute.
What is the count rate of the sample after 18 hours?
A.100 counts per minute
B.200 counts per minute
C.267 counts per minute
D.400 counts per minute
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解題
First, determine the number of half-lives that have passed in 18 hours: $$\text{number of half-lives} = \frac{18\text{ hours}}{6.0\text{ hours}} = 3.0$$
Now, calculate the count rate after 3 half-lives: - Initial count rate: $800\text{ counts/minute}$ - After 1 half-life: $\frac{800}{2} = 400\text{ counts/minute}$ - After 2 half-lives: $\frac{400}{2} = 200\text{ counts/minute}$ - After 3 half-lives: $\frac{200}{2} = 100\text{ counts/minute}$