Question 1: Subtopic 1.1
Forces of 3N and 4N act at right angles, as shown.
What is the resultant force?
A) 1N along XZ
B) 5N along XZ
C) 5N along OY
D) 7N along OY
▶️Answer/Explanation
Answer: C
Question 2: Subtopic 1.2
A light ball is held at rest at the top of a tall cliff. It is released and falls through the air, eventually reaching its terminal velocity.
Which row describes the behaviour of the ball as it descends?
| the initial acceleration of the ball | the final acceleration of the ball | |
|---|---|---|
| A | 0 | 0 |
| B | 0 | g |
| C | g | 0 |
| D | g | g |
▶️Answer/Explanation
Answer: C) g, 0
Explanation: Initially, the ball is in free fall, so its acceleration is equal to the acceleration due to gravity, \( g \). As it reaches terminal velocity, the air resistance balances the gravitational force, resulting in zero acceleration.
Question 3: Subtopic 1.2
The graph represents the motion of a car.
How far has the car moved between 0 and 5 s?
A) 2 m
B) 10 m
C) 25 m
D) 50 m
▶️Answer/Explanation
Answer: C) 25 m
Explanation: The distance traveled by the car can be calculated by finding the area under the speed-time graph. The graph shows a constant speed of 5 m/s over 5 seconds, so the distance is:
\[ \text{Distance} = \text{Speed} \times \text{Time} = 5 \, \text{m/s} \times 5 \, \text{s} = 25 \, \text{m} \]
Question 4: Subtopic 1.3
Which statement about mass or weight is not correct?
A) Masses can be compared using a balance.
B) Mass is a force.
C) Weights can be compared using a balance.
D) Weight is a force.
▶️Answer/Explanation
Answer: B) Mass is a force.
Explanation: Mass is a measure of the amount of matter in an object and is not a force. Weight, on the other hand, is the force exerted on an object due to gravity and is measured in newtons (N).
Question 5: Subtopic 1.3
A sphere P, made of steel, has a weight of 10 N on Earth. Another sphere Q, also made of steel, has a weight of 10 N on Mars. The gravitational field strength on Earth is greater than the gravitational field strength on Mars.
Which statement is correct?
A) The mass of sphere P is the same as the mass of sphere Q.
B) The mass of sphere P is less than the mass of sphere Q.
C) On Mars, the weight of sphere P is the same as the weight of sphere Q.
D) On Earth, the weight of sphere Q is less than 10 N.
▶️Answer/Explanation
Answer: B) The mass of sphere P is less than the mass of sphere Q.
Explanation: Since the gravitational field strength on Mars is less than on Earth, sphere Q must have a greater mass to have the same weight (10 N) on Mars. Therefore, the mass of sphere P is less than the mass of sphere Q.
Question 6: Subtopic 1.4
Which two quantities must be known to determine the density of a material?
A) mass and area
B) mass and volume
C) weight and area
D) weight and volume
▶️Answer/Explanation
Answer: B) mass and volume
Explanation: Density is defined as mass per unit volume, so both mass and volume are required to calculate density.
Question 7: Subtopic 1.5
A truck is towing a car along a straight horizontal road at a constant speed.
The rope breaks.
Which row gives the direction of the initial acceleration of the truck after the rope breaks and the reason for the acceleration?
| direction of acceleration of the truck | reason | |
|---|---|---|
| A | left | the driving force is greater than the resistive forces on the truck |
| B | left | the driving force is smaller than the resistive forces on the truck |
| C | right | the driving force is greater than the resistive forces on the truck |
| D | right | the driving force is smaller than the resistive forces on the truck |
▶️Answer/Explanation
Answer: C) right, the driving force is greater than the resistive forces on the truck
Explanation: When the rope breaks, the driving force of the truck is no longer balanced by the resistive forces (friction, air resistance, etc.), so the truck accelerates in the direction of the driving force, which is to the right.
Question 8: Subtopic 1.5 (Forces)
A uniform beam is pivoted at the centre and two identical masses, X and Y, are placed so that the beam balances.
A smaller mass is then added at the position shown.
How can the masses be positioned so the beam balances again?
A) Move X away from the pivot.
B) Move X towards the pivot.
C) Move Y towards the pivot.
D) Move the small mass away from the pivot.
▶️Answer/Explanation
Answer: B) Move X towards the pivot.
Explanation: To balance the beam after adding the smaller mass, the moment (torque) on one side must equal the moment on the other side. Moving mass X towards the pivot reduces its moment, helping to balance the additional moment created by the smaller mass.
Question 9: Subtopic 1.5
A resultant force of 2.0 N acts on an object of mass 3.0 kg for 6.0 s.
What is the change in velocity of the object?
A) 0.25 m/s
B) 1.0 m/s
C) 4.0 m/s
D) 36 m/s
▶️Answer/Explanation
Answer: C) 4.0 m/s
Explanation: Using Newton’s second law, \( F = ma \), the acceleration \( a \) is:
\[ a = \frac{F}{m} = \frac{2.0 \, \text{N}}{3.0 \, \text{kg}} = \frac{2}{3} \, \text{m/s}^2 \]
The change in velocity \( \Delta v \) is then:
\[ \Delta v = a \times t = \frac{2}{3} \, \text{m/s}^2 \times 6.0 \, \text{s} = 4.0 \, \text{m/s} \]
Question 10: Subtopic 1.7
The diagram shows the energy stores for a mobile (cell) phone and how the energy is transferred between stores.
What describes how the chemical energy is transferred?
A) electrical work done
B) mechanical work done
C) electromagnetic waves
D) sound waves
▶️Answer/Explanation
Answer: A) electrical work done
Explanation: In a mobile phone, chemical energy from the battery is converted into electrical energy, which is then used to power the phone’s components. This process involves electrical work done.
Question 11: Subtopic 1.7
A wind turbine is 30% efficient and has an output of 2.5 MW of electrical power.
What is the power input to the turbine?
A) 0.75 MW
B) 8.3 MW
C) 75 MW
D) 83 MW
▶️Answer/Explanation
Answer: B) 8.3 MW
Explanation: Efficiency is given by the ratio of useful output power to input power. Rearranging the formula for efficiency:
\[ \text{Efficiency} = \frac{\text{Output Power}}{\text{Input Power}} \]
\[ \text{Input Power} = \frac{\text{Output Power}}{\text{Efficiency}} = \frac{2.5 \, \text{MW}}{0.30} = 8.3 \, \text{MW} \]
Question 12: Subtopic 1.7
Which two physical quantities must be used to calculate the power developed by a student running up a flight of steps?
A) force exerted and the vertical height of the steps only
B) force exerted and the time taken only
C) work done and the vertical height of the steps only
D) work done and the time taken only
▶️Answer/Explanation
Answer: D) work done and the time taken only
Explanation: Power is defined as the rate at which work is done. Therefore, to calculate power, you need to know the work done (which is force × distance) and the time taken to do that work.
Question 13: Subtopic 1.8
The density of sea water is \(1030 \, \text{kg/m}^3\). The gravitational field strength on the Earth is \(9.8 \, \text{N/kg}\). Atmospheric pressure is \(101 \, 000 \, \text{Pa}\).
At which depth in sea water is the total pressure due to the atmosphere and the water equal to \(513 \, 000 \, \text{Pa}\)?
A) 40.8 m
B) 50.8 m
C) 400 m
D) 498 m
▶️Answer/Explanation
Answer: A) 40.8 m
Explanation: The total pressure at a depth \( h \) in a fluid is given by:
\[ P_{\text{total}} = P_{\text{atm}} + \rho g h \]
Rearranging to solve for \( h \):
\[ h = \frac{P_{\text{total}} – P_{\text{atm}}}{\rho g} = \frac{513 \, 000 \, \text{Pa} – 101 \, 000 \, \text{Pa}}{1030 \, \text{kg/m}^3 \times 9.8 \, \text{N/kg}} \]
\[ h = \frac{412 \, 000}{10 \, 094} \approx 40.8 \, \text{m} \]
Question 14: Subtopic 2.1
Four students describe the phrase ‘absolute zero’ during a lesson on the particle model.
Which student is correct?
A) This is the lowest possible temperature.
B) Particles in a solid start vibrating.
C) Particles do not have any weight.
D) Particles have the least gravitational potential energy.
▶️Answer/Explanation
Answer: A) This is the lowest possible temperature.
Explanation: Absolute zero is the lowest possible temperature, at which particles have minimal kinetic energy and all thermal motion ceases.
Question 15: Subtopic 2.1
Four students are asked to state and explain the relative magnitudes of the thermal expansion of solids and gases.
Which student is correct?
A) Gases expand more than solids because the molecules in a gas are in random motion.
B) Gases expand more than solids because the attractive forces between molecules are much weaker in gases.
C) Solids expand more than gases because the molecules are closer together in solids.
D) Solids expand more than gases because the molecules in a solid are in a regular pattern.
▶️Answer/Explanation
Answer: B) Gases expand more than solids because the attractive forces between molecules are much weaker in gases.
Explanation: Gases expand more than solids because the intermolecular forces in gases are much weaker, allowing the molecules to move more freely and expand more when heated.
Question 16: Subtopic 2.3
Four cups A, B, C and D contain hot coffee.
Which cup keeps the coffee warm the longest?
| the outside surface of the cup | the top of the cup | |
|---|---|---|
| A | black | covered with a lid |
| B | black | no lid |
| C | white | covered with a lid |
| D | white | no lid |
▶️Answer/Explanation
Answer: C) white, covered with a lid
Explanation: A white surface reflects more thermal radiation than a black surface, reducing heat loss. A lid reduces heat loss through convection and evaporation, keeping the coffee warmer for longer.
Question 17: Subtopic 3.1
The diagram shows a wave.
What are the amplitude and the wavelength of this wave?
| amplitude/cm | wavelength/cm | |
|---|---|---|
| A | 3 | 4 |
| B | 3 | 8 |
| C | 6 | 4 |
| D | 6 | 8 |
▶️Answer/Explanation
Answer: B) 3 cm, 8 cm
Explanation: The amplitude is the maximum displacement from the equilibrium position, which is 3 cm. The wavelength is the distance between two consecutive crests or troughs, which is 8 cm.
Question 18: Subtopic 3.1
Optical fibres are used to transmit digital signals using infrared radiation. The average refractive index of the fibres is 1.50.
Which row describes a digital signal and gives the speed of infrared radiation in the fibres?
| digital signal | speed of infrared radiation in the fibres m/s | |
|---|---|---|
| A | a signal that consists of only two values | \( 2.0 \times 10^8 \) |
| B | a signal that consists of only two values | \( 4.5 \times 10^8 \) |
| C | a signal that consists of a continuous range of values | \( 2.0 \times 10^8 \) |
| D | a signal that consists of a continuous range of values | \( 4.5 \times 10^8 \) |
▶️Answer/Explanation
Answer: A) a signal that consists of only two values, \( 2.0 \times 10^8 \) m/s
Explanation: A digital signal consists of only two values (e.g., 0 and 1). The speed of light in a medium is given by \( v = \frac{c}{n} \), where \( c \) is the speed of light in a vacuum (\( 3.0 \times 10^8 \) m/s) and \( n \) is the refractive index. For \( n = 1.50 \), the speed is:
\[ v = \frac{3.0 \times 10^8}{1.50} = 2.0 \times 10^8 \, \text{m/s} \]
Question 19: Subtopic 3.2
Which statement describes monochromatic light?
A) light of a single frequency
B) light transmitted by a transparent prism
C) visible light
D) white light
▶️Answer/Explanation
Answer: A) light of a single frequency
Explanation: Monochromatic light consists of light of a single frequency (or wavelength).
Question 20: Subtopic 3.2
A beam of light consists of yellow and blue light. The beam of light is incident on a glass prism. Which diagram is correct?
▶️Answer/Explanation
Answer: D) glass prism
Explanation: When light passes through a prism, it is dispersed into its constituent colors. Blue light is refracted more than yellow light due to its shorter wavelength, so the blue light will bend more.
Question 21: Subtopic 3.3
A radio station broadcasts a signal with a frequency of 89 MHz. What is the wavelength of this signal?
A) 3.7 µm
B) 3.4 m
C) 3.7 km
D) 3.4 Mm
▶️Answer/Explanation
Answer: B) 3.4 m
Explanation: The wavelength \( \lambda \) of a wave is given by:
\[ \lambda = \frac{c}{f} \]
where \( c \) is the speed of light (\( 3.0 \times 10^8 \, \text{m/s} \)) and \( f \) is the frequency (89 MHz = \( 89 \times 10^6 \, \text{Hz} \)).
\[ \lambda = \frac{3.0 \times 10^8}{89 \times 10^6} \approx 3.4 \, \text{m} \]
Question 22: Subtopic 3.4
A boy shouts and hears the echo from a tall building 2.2 s later. The speed of sound in air is 330 m/s. How far away from the boy is the building?
A) 150 m
B) 300 m
C) 360 m
D) 730 m
▶️Answer/Explanation
Answer: C) 360 m
Explanation: The distance \( d \) to the building can be calculated using the time \( t \) it takes for the sound to travel to the building and back:
\[ d = \frac{v \times t}{2} = \frac{330 \, \text{m/s} \times 2.2 \, \text{s}}{2} = 363 \, \text{m} \]
Rounding to two significant figures, the distance is approximately 360 m.
Question 23: Subtopic 4.1
The magnetic field of a bar magnet can be represented by magnetic field lines.
Which diagram shows two magnetic field lines correctly?
▶️Answer/Explanation
Answer: A) N S
Explanation: Magnetic field lines always emerge from the north pole (N) and enter the south pole (S) of a magnet. The correct diagram shows field lines curving from N to S.
Question 24: Subtopic 4.2
A plastic rod is rubbed with a dry cloth. The rod becomes positively charged.
Why has the rod become positively charged?
A) It has gained electrons.
B) It has gained neutrons.
C) It has lost electrons.
D) It has lost neutrons.
▶️Answer/Explanation
Answer: C) It has lost electrons.
Explanation: When a plastic rod is rubbed with a dry cloth, electrons are transferred from the rod to the cloth. The rod loses electrons and becomes positively charged.
Question 25: Subtopic 4.2
Which statement about electric current in a conductor is correct?
A) In a d.c. circuit, the electric current gradually decreases along the conductor.
B) In a d.c. circuit, the free electrons flow back and forth.
C) In an a.c. circuit, the electric current remains exactly the same all the time.
D) In an a.c. circuit, the flow of charge changes direction continually.
▶️Answer/Explanation
Answer: D) In an a.c. circuit, the flow of charge changes direction continually.
Explanation: In an alternating current (a.c.) circuit, the direction of the current changes periodically, typically 50 or 60 times per second, depending on the frequency of the supply.
Question 26: Subtopic 4.2
A piece of metal wire X with a uniform diameter has resistance \( R \).
A second piece of wire Y is made of the same metal and has a uniform diameter. Y has double the cross-sectional area of X and half the length of X.
What is the resistance of Y?
A) \(\frac{R}{4}\)
B) \(\frac{R}{2}\)
C) \( R \)
D) \( 4R \)
▶️Answer/Explanation
Answer: A) \(\frac{R}{4}\)
Explanation: The resistance \( R \) of a wire is given by:
\[ R = \rho \frac{L}{A} \]
where \( \rho \) is the resistivity, \( L \) is the length, and \( A \) is the cross-sectional area. For wire Y, the length is halved (\( \frac{L}{2} \)) and the area is doubled (\( 2A \)). Therefore, the resistance of Y is:
\[ R_Y = \rho \frac{\frac{L}{2}}{2A} = \rho \frac{L}{4A} = \frac{R}{4} \]
Question 27: Subtopic 4.2
An electric fire is connected to a 240 V supply and transfers energy at a rate of 1.0 kW.
How much charge passes through the fire in 1.0 h?
A) 42 C
B) 250 C
C) \( 1.5 \times 10^4 \) C
D) \( 2.4 \times 10^5 \) C
▶️Answer/Explanation
Answer: C) \( 1.5 \times 10^4 \) C
Explanation: The power \( P \) is given by:
\[ P = IV \]
Rearranging for current \( I \):
\[ I = \frac{P}{V} = \frac{1000 \, \text{W}}{240 \, \text{V}} \approx 4.17 \, \text{A} \]
The charge \( Q \) is then:
\[ Q = I \times t = 4.17 \, \text{A} \times 3600 \, \text{s} \approx 1.5 \times 10^4 \, \text{C} \]
Question 28: Subtopic 4.3
Two lamps are connected in parallel.
Which switches must be closed so that both lamps light?
A) \( S_1 \) and \( S_2 \) only
B) \( S_1 \) and \( S_3 \) only
C) \( S_2 \) and \( S_3 \) only
D) \( S_1 \), \( S_2 \) and \( S_3 \)
▶️Answer/Explanation
Answer: D) \( S_1 \), \( S_2 \) and \( S_3 \)
Explanation: In a parallel circuit, all switches must be closed to ensure that both lamps are connected to the power supply and can light up.
Question 29: Subtopic 4.3
The diagram shows a circuit that switches on a lamp when there is a change in the environment.
Which change in the environment causes the lamp to be switched on?
A) a decrease in light intensity
B) a decrease in temperature
C) an increase in light intensity
D) an increase in temperature
▶️Answer/Explanation
Answer: D) an increase in temperature
Explanation: The circuit likely contains a thermistor, which decreases in resistance as temperature increases. This would allow more current to flow, switching on the lamp.
Question 30: Subtopic 4.5
A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c. The current in the primary coil is 0.50 A.
What is the current in the secondary coil?
A) 0.13 A
B) 0.50 A
C) 2.0 A
D) 8.0 A
▶️Answer/Explanation
Answer: C) 2.0 A
Explanation: For a 100% efficient transformer, the power in the primary coil equals the power in the secondary coil:
\[ V_p I_p = V_s I_s \]
Rearranging for \( I_s \):
\[ I_s = \frac{V_p I_p}{V_s} = \frac{240 \, \text{V} \times 0.50 \, \text{A}}{60 \, \text{V}} = 2.0 \, \text{A} \]
Question 31: Subtopic 4.5
The diagram shows the pattern of the magnetic field due to the current \( I \) in a straight wire.
Which row is correct?
| direction of field | relative strength of field | |
|---|---|---|
| A | X | greater at P than Q |
| B | Y | greater at P than Q |
| C | X | greater at Q than P |
| D | Y | greater at Q than P |
▶️Answer/Explanation
Answer: D) Y, greater at Q than P
Explanation: The magnetic field around a straight current-carrying wire forms concentric circles. The field strength is inversely proportional to the distance from the wire, so it is greater at point Q (closer to the wire) than at point P (farther from the wire). The direction of the field is given by the right-hand rule, which corresponds to direction Y.
Question 32: Subtopic 4.5
In which device is the magnetic effect of a current not used?
A) electromagnet
B) loudspeaker
C) potential divider
D) relay
▶️Answer/Explanation
Answer: C) potential divider
Explanation: A potential divider is a circuit that divides voltage using resistors and does not rely on the magnetic effect of a current. Electromagnets, loudspeakers, and relays all use the magnetic effect of a current.
Question 33: Subtopic 5.2
Fission and fusion are two types of nuclear process.
How does the total mass of the nuclides produced compare with the total mass of the original nuclide or nuclides in these nuclear processes?
| total mass of fission products compared to original nuclide | total mass of fusion products compared to original nuclides | |
|---|---|---|
| A | same | same |
| B | more | less |
| C | less | more |
| D | less | less |
▶️Answer/Explanation
Answer: D) less, less
Explanation: In both fission and fusion, the total mass of the products is less than the total mass of the original nuclides. The “missing” mass is converted into energy according to Einstein’s equation \( E = mc^2 \).
Question 34: Subtopic 5.1
The table shows the composition of three different nuclei.
| nucleus | number of protons | number of neutrons |
|---|---|---|
| X | 3 | 3 |
| Y | 3 | 4 |
| Z | 4 | 3 |
Which nuclei are isotopes of the same element?
A) X, Y and Z
B) X and Y only
C) X and Z only
D) Y and Z only
▶️Answer/Explanation
Answer: B) X and Y only
Explanation: Isotopes of the same element have the same number of protons but different numbers of neutrons. Nuclei X and Y both have 3 protons, so they are isotopes of the same element. Nucleus Z has 4 protons, so it is a different element.
Question 35: Subtopic 5.2
Which change occurs in the nucleus of a radioactive atom during β-emission?
A) A neutron transforms into a proton and an electron.
B) A neutron transforms into a proton only.
C) A proton transforms into a neutron and an electron.
D) A proton transforms into a neutron only.
▶️Answer/Explanation
Answer: A) A neutron transforms into a proton and an electron.
Explanation: During β-emission, a neutron in the nucleus decays into a proton, an electron (the β-particle), and an antineutrino. The proton remains in the nucleus, while the electron is emitted.
Question 36: Subtopic 5.2
A radioactive isotope has a half-life of 8 days. A detector close to a sample of this isotope gives a count rate of 200 counts per minute. Without the source, the background count is 20 counts per minute.
What is the count rate due to the source after 8 days?
A) 80 counts per minute
B) 90 counts per minute
C) 100 counts per minute
D) 110 counts per minute
▶️Answer/Explanation
Answer: B) 90 counts per minute
Explanation: After one half-life (8 days), the count rate due to the source will halve. The initial count rate due to the source is:
\[ 200 \, \text{counts/min} – 20 \, \text{counts/min} = 180 \, \text{counts/min} \]
After 8 days, the count rate due to the source will be:
\[ \frac{180}{2} = 90 \, \text{counts/min} \]
Adding the background count rate:
\[ 90 + 20 = 110 \, \text{counts/min} \]
However, the question asks for the count rate due to the source only, which is 90 counts per minute.
Question 37: Subtopic 6.1
Which statement about the Solar System is correct?
A) All the planets are rocky.
B) Only the Earth has a moon.
C) Pluto is a dwarf planet.
D) There are many stars in the Solar System.
▶️Answer/Explanation
Answer: C) Pluto is a dwarf planet.
Explanation: Pluto is classified as a dwarf planet. The Solar System contains only one star, the Sun, and many planets have moons.
Question 38: Subtopic 6.1
Comets are bodies which orbit the Sun in the Solar System.
What is the shape of the orbit and how is the Sun positioned within the orbit?
| shape of orbit | position of the Sun | |
|---|---|---|
| A | circular | centre of orbit |
| B | circular | not at centre of orbit |
| C | elliptical | centre of orbit |
| D | elliptical | not at centre of orbit |
▶️Answer/Explanation
Answer: D) elliptical, not at centre of orbit
Explanation: Comets have highly elliptical orbits, and the Sun is located at one of the foci of the ellipse, not at the centre.
Question 39: Subtopic 6.2
Which nuclear reaction produces the release of energy to power a star?
A) nuclear fission of helium into hydrogen
B) nuclear fission of hydrogen into helium
C) nuclear fusion of helium into hydrogen
D) nuclear fusion of hydrogen into helium
▶️Answer/Explanation
Answer: D) nuclear fusion of hydrogen into helium
Explanation: Stars, including the Sun, generate energy through the nuclear fusion of hydrogen nuclei (protons) into helium nuclei. This process releases a tremendous amount of energy.
Question 40: Subtopic 6.2
What is the definition of the Hubble constant?
A) the ratio of the speed at which a galaxy is receding from the Earth to its distance from the Earth
B) the value of the change in wavelength of the galaxy’s starlight due to redshift
C) the constant used to represent the rate of expansion of the Universe in all directions
D) the estimated constant equal to the age of the Universe
▶️Answer/Explanation
Answer: A) the ratio of the speed at which a galaxy is receding from the Earth to its distance from the Earth
Explanation: The Hubble constant \( H_0 \) is defined as the ratio of the speed at which a galaxy is receding from the Earth to its distance from the Earth. It is a measure of the rate of expansion of the Universe.