▶️ Answer/Explanation
Detailed solution:
The volume of a solid cube with regular sides is found by measuring its dimensions with a ruler and calculating $V = l \times w \times h$.
The volume of a liquid is measured directly by pouring it into a measuring cylinder and reading the meniscus level.
Option D correctly pairs the ruler for the cube and the measuring cylinder for the liquid.
Other options incorrectly pair the apparatus with the measurement task.
▶️ Answer/Explanation
Detailed solution:
The given speed-time graph displays a straight diagonal line going downwards, representing constant deceleration to a stop.
On a distance-time graph, the gradient (or slope) at any given point represents the object’s speed.
Since the speed is constantly decreasing, the gradient of the distance-time graph must start steep and progressively become flatter.
Graph B perfectly illustrates this relationship, showing a curve with a decreasing positive slope that eventually becomes horizontal as the object stops.
▶️ Answer/Explanation
Detailed solution:
To find the distance travelled from a speed–time graph, we need to calculate the area under the line.
For the time interval between 0 and 5 s, the graph shows a constant speed of 5 m/s.
The shape formed under the graph is a rectangle with a base of 5 s and a height of 5 m/s.
Calculating the area: Area = base × height = 5 s × 5 m/s = 25 m.
Therefore, the car has moved 25 m, which corresponds to Option C.
▶️ Answer/Explanation
Detailed solution:
Mass is defined as the measure of the quantity of matter in an object, making it a scalar quantity and not a force.
Weight is the gravitational force acting on an object that has mass.
Both masses and weights can be reliably compared using a balance.
Therefore, the statement “Mass is a force” is fundamentally incorrect.
This matches Option B.
▶️ Answer/Explanation
Detailed solution:
Density ($\rho$) is defined as the mass per unit volume of a material. [cite: 194]
This relationship is mathematically expressed by the formula: $\rho = \frac{m}{V}$. [cite: 195]
Therefore, to determine a material’s density, you explicitly need to measure its mass ($m$) and its volume ($V$). [cite: 194]
Weight is a gravitational force, and area is a two-dimensional measure, neither of which are used in this standard calculation. [cite: 192]
This makes Option B the correct choice.
▶️ Answer/Explanation
Detailed solution:
The moment of a force is a measure of its turning effect around a pivot point.
It is defined and calculated using the equation: moment = force × perpendicular distance from the pivot.
In this scenario, the downward force acting on the see-saw is the weight of each boy.
Therefore, the moment exerted by each boy is determined by both his weight and his horizontal distance from the pivot.
This makes Option D the correct choice.
▶️ Answer/Explanation
Detailed solution:
According to the principle of moments, the anticlockwise moment must equal the clockwise moment.
The anticlockwise moment is $25 \times (50 – 30) = 500$ g·cm.
To restore equilibrium using the smallest possible mass, it must be placed at the maximum distance from the pivot.
The maximum distance on the opposite side of the 100 cm rule is 50 cm (placed exactly at the 100 cm mark).
Equating the moments gives $m \times 50 = 500$, which solves to $m = 10$ g, matching Option B.
▶️ Answer/Explanation
Detailed solution:
The uniform beam’s 4.0 N weight acts at its center of gravity, which is 50 cm from end X.
The pivot is at 60 cm, making the lever arms: 8.0 N load = 50 cm, beam weight = 10 cm, and force F = 20 cm.
By the principle of moments: Total Anticlockwise Moment = Total Clockwise Moment.
(8.0 N × 50 cm) + (4.0 N × 10 cm) = F × 20 cm.
400 + 40 = 20F, which simplifies to 440 = 20F.
Therefore, solving for F gives 22 N.
▶️ Answer/Explanation
Detailed solution:
The stability of an object depends on the height of its centre of gravity above its base.
An object is more stable when its centre of gravity is lower, as a greater angle of tilt is required before its weight causes it to topple.
In the diagram, toy X has the lowest centre of gravity (point P), making it the most stable.
Conversely, toy Z has the highest centre of gravity, making it the least stable.
Therefore, X is the most stable and Z is the least stable, matching Option B.
▶️ Answer/Explanation
Detailed solution:
A mobile phone is powered by a battery, which functions as a chemical energy store.
When the phone is in use, this chemical energy is transferred to other components via an electric current.
According to the syllabus, energy transfer by electrical currents is defined as electrical work done.
Therefore, the process describing how chemical energy moves from the battery store is electrical work.
This matches Option A.
▶️ Answer/Explanation
Detailed solution:
Work done ($W$) is defined as the product of the force ($F$) and the distance ($d$) moved in the direction of the force .
Using the formula $W = F \times d$, substitute the given values: $W = 50\text{ N} \times 5.0\text{ m}$.
Calculating the product gives $W = 250\text{ J}$.
This matches the value provided in Option D.
▶️ Answer/Explanation
Detailed solution:
Power is defined as the rate at which work is done or the rate at which energy is transferred .
The standard formula for power is $P = \frac{W}{t}$, where $W$ represents work done and $t$ represents the time taken .
While work done can be further calculated as force multiplied by distance, the primary definition relies on work and time.
Therefore, to calculate the power developed by the student, both work done and time taken are essential quantities.
This corresponds directly to Option D.
▶️ Answer/Explanation
Detailed solution:
Pressure is defined as $P = F/A$. In Diagram 1, the base area is $1\text{m} \times 5\text{m} = 5\text{m}^2$, resulting in a pressure of $125\,000\text{N} / 5\text{m}^2 = 25\,000\text{ Pa}$.
In Diagram 2, the base area is $1\text{m} \times 1\text{m} = 1\text{m}^2$, making the pressure $125\,000\text{N} / 1\text{m}^2 = 125\,000\text{ Pa}$.
The change in pressure is $125\,000\text{ Pa} – 25\,000\text{ Pa} = 100\,000\text{ Pa}$.
This represents an increase of $100\,000\text{ N/m}^2$, matching Option B.
▶️ Answer/Explanation
Detailed solution:
Absolute zero is defined as the lowest theoretical temperature achievable, equivalent to 0 K or approximately −273 ∘ C.
At this temperature, the kinetic energy of particles reaches its absolute minimum.
Since internal energy is related to particle motion, as temperature decreases, particles move less until they have the least possible energy.
Options B, C, and D are incorrect as they do not describe the fundamental temperature limit or its effect on internal energy.
Therefore, student A provides the correct description of absolute zero.
▶️ Answer/Explanation
Detailed solution:
Molecules in a liquid have a range of kinetic energies; some move faster than others.
Particles at the surface with high enough energy can overcome the attractive forces of neighboring molecules and escape as gas.
This specific surface-level process is known as evaporation and can occur at any temperature.
In contrast, boiling involves the formation of bubbles throughout the entire liquid, not just at the surface.
Therefore, the correct term for surface-based escape is evaporation, matching Option C.
▶️ Answer/Explanation
Detailed solution:
In this experiment, heat is applied to the top of the water while the bottom stays cold.
Since hot water is less dense, it remains at the top, preventing heat transfer via convection to the bottom.
Any heat reaching the bottom would have to travel through the water by conduction.
Because the bottom remains cold even when the top boils, it proves water does not conduct heat well.
Therefore, the experiment concludes that water is a bad conductor, matching Option A.
▶️ Answer/Explanation
Detailed solution:
The amplitude is the maximum displacement from the equilibrium position to a crest or trough; the diagram shows this vertical distance is $3\text{ cm}$.
The wavelength is the horizontal distance between two consecutive identical points, such as from one crest to the next.
From the diagram, one complete wave cycle spans a horizontal distance of $8\text{ cm}$.
Therefore, the amplitude is $3\text{ cm}$ and the wavelength is $8\text{ cm}$.
This corresponds to the values provided in Option B.
▶️ Answer/Explanation
Detailed solution:
According to the law of reflection, the angle of incidence is always equal to the angle of reflection.
The angle of incidence is defined as the angle between the incident ray and the normal to the mirror.
The angle of reflection is defined as the angle between the reflected ray and the normal.
Therefore, the angle between the incident ray and the normal is the correct equivalent.
This corresponds to Option B.
▶️ Answer/Explanation
Detailed solution:
The focal length is defined as the distance from the optical centre of the lens to its principal focus.
Rays of light that pass through the principal focus emerge parallel to the principal axis after passing through a converging lens.
In the diagram, the rays originate from a single point and become parallel, identifying that point as the principal focus.
Distance B measures the span between the center of the lens and this focal point.
Therefore, B represents the focal length of the lens.
▶️ Answer/Explanation
Detailed solution:
When a beam of light enters a prism, it undergoes refraction and dispersion because different colors have different refractive indices in glass.
Blue light has a shorter wavelength and a higher frequency than yellow light, causing it to slow down more and refract (bend) at a greater angle.
In the diagrams, blue light should be positioned further away from the original path of the incident beam than yellow light.
Diagram D correctly shows both colors bending toward the normal upon entry and away from the normal upon exit, with blue light deviating more than yellow light.
This correctly demonstrates the dispersion of light within a glass prism.
▶️ Answer/Explanation
Detailed solution:
Medical scanning, such as imaging broken bones, typically utilizes X-rays due to their ability to penetrate soft tissue while being absorbed by dense materials .
Television remote controllers operate using infrared radiation to transmit short-range signals.
Comparing these requirements to the table, the medical scanner uses X-rays and the remote controller uses infrared.
This combination corresponds to the row for Option C.
▶️ Answer/Explanation
Detailed solution:
An echo involves sound travelling to the building and back, so the total distance is 2×distance to building(d).
Using the formula distance=speed×time, the total travel distance is 330 m/s×2.2 s=726 m.
To find the distance to the building, divide the total distance by 2: d=726 m/2=363 m.
Rounding to two significant figures as per the options, the distance is approximately 360 m.
This matches Option C.
▶️ Answer/Explanation
Detailed solution:
Magnetic field lines indicate the direction of the force on a North pole, always pointing from the North pole toward the South pole outside the magnet.
Diagram A correctly shows the lines emerging from the North (N) and entering the South (S).
The lines must also be continuous loops and should not cross each other.
Options B, C, and D are incorrect as they show either reversed directions or lines pointing away from both poles.
Therefore, Option A is the only correct representation of the magnetic field pattern.
▶️ Answer/Explanation
Detailed solution:
Charging by friction occurs because of the transfer of electrons between two surfaces.
Electrons are negatively charged particles; protons and neutrons remain fixed in the nucleus.
For an object to become positively charged, it must have a deficit of negative charges.
In this case, rubbing causes electrons to move from the plastic rod to the dry cloth.
This loss of electrons leaves the rod with an overall positive charge, matching Option C.
▶️ Answer/Explanation
Detailed solution:
Direct current (d.c.) involves charge flowing in one constant direction, while alternating current (a.c.) involves charge changing direction periodically .
In a d.c. circuit, current is conserved and does not decrease along a single conductor.
Free electrons in a d.c. circuit move in one direction, whereas they oscillate back and forth in an a.c. circuit.
In an a.c. circuit, the magnitude and direction of the current vary over time rather than remaining constant.
Therefore, statement D is the only correct description of alternating current behavior.
▶️ Answer/Explanation
Detailed solution:
To determine the resistance of a component, you must measure the potential difference (V) across it and the current (I) flowing through it.
The ammeter must be connected in series with the resistor to measure the current correctly.
The voltmeter must be connected in parallel across the resistor to measure the potential difference.
In circuit B, the ammeter is in series and the voltmeter is in parallel with the resistor, allowing for the calculation R=V/I.
Therefore, circuit B is the only setup that correctly positions both meters for this measurement.
▶️ Answer/Explanation
Detailed solution:
To find the energy transferred, use the formula E=V×I×t, where V is voltage, I is current, and t is time.
Substitute the given values into the equation: E=12 V×2.0 A×60 s.
Calculating the product gives E=1440 J.
Among the given choices, 1400 J is the closest approximate value.
Therefore, the correct choice is Option D.
▶️ Answer/Explanation
Detailed solution:
In the given circuit, ammeters B and C are connected in separate parallel branches, measuring only the current flowing through their respective resistors.
Ammeter D is placed in the main part of the circuit directly connected to the battery source.
According to the rules of parallel circuits, the total current entering a junction must equal the sum of the currents in the branches.
Therefore, the current at D is the sum of the currents passing through B and C, making it the largest reading.
This corresponds to Option D.
▶️ Answer/Explanation
Detailed solution:
Switch S₁ is in the main branch, so it must be closed for any current to flow from the power supply.
Switches S₂ and S₃ are in separate parallel branches, each controlling one of the two lamps.
To light the first lamp, both S₁ and S₂ must be closed; to light the second lamp, both S₁ and S₃ must be closed.
Therefore, for both lamps to light simultaneously, all three switches S₁, S₂, and S₃ must be closed.
This corresponds to Option D.
▶️ Answer/Explanation
Detailed solution:
Switches and fuses must be connected to the live wire to ensure safety .
When the switch is open, this arrangement disconnects the device from the high-voltage supply .
If a switch were on the neutral wire, the device would remain “live” even when turned off, posing a shock risk .
Regarding other options: double-insulated devices still require fuses to protect against excess current .
A fuse rating must be slightly higher than the operating current to prevent unnecessary blowing.
▶️ Answer/Explanation
Detailed solution:
An electromotive force (e.m.f.) is induced when a conductor moves across a magnetic field or when a magnetic field linking a conductor changes .
The magnitude of this induced voltage depends on the rate at which the magnetic field lines are cut or changed.
Moving the magnet quickly creates a higher rate of change in the magnetic field compared to moving it slowly.
Stationary magnets (Options B and D) do not cause a change in magnetic field linkage, resulting in zero induced voltage.
Therefore, quickly removing the magnet produces the greatest induced voltage, matching Option C.
▶️ Answer/Explanation
Detailed solution:
Electromagnets, loudspeakers, and relays all utilize the magnetic field generated by an electric current to operate mechanical parts or produce sound.
A potential divider is a purely resistive circuit used to scale down voltage and does not involve magnetic fields or electromagnetic induction.
Therefore, it is the only device listed that does not use the magnetic effect of a current.
This corresponds to Option C.
▶️ Answer/Explanation
Detailed solution:
In long-distance electricity transmission, transformer X must be a step-up transformer to increase voltage and minimize energy loss in cables.
Transformer Y is located near the destination to decrease the voltage to a safe level for domestic use, making it a step-down transformer.
Step-up transformers increase potential difference, while step-down transformers decrease it.
This configuration ensures efficiency during transit and safety at the point of use.
Therefore, X is step-up and Y is step-down, matching Option C.
▶️ Answer/Explanation
Detailed solution:
The nuclear model of the atom states that the mass and positive charge are concentrated in a central nucleus .
Protons (positively charged) and neutrons (neutral) are located inside this nucleus .
Electrons (negatively charged) move in orbits around the outside of the nucleus.
Diagram A correctly shows the positive charges in the center and negative charges in orbit.
Therefore, Option A is the correct representation of the charged particles.
▶️ Answer/Explanation
Detailed solution:
Isotopes of the same element must have the same number of protons (atomic number) but different numbers of neutrons.
Looking at the table, nucleus X and nucleus Y both have 3 protons, which identifies them as the same element.
Nucleus X has 3 neutrons, while nucleus Y has 4 neutrons, satisfying the condition for isotopes.
Nucleus Z has 4 protons, meaning it belongs to a different chemical element entirely.
Therefore, only X and Y are isotopes of the same element, which corresponds to Option B.
▶️ Answer/Explanation
Detailed solution:
First, calculate the reduction factor in activity: 9600/600=16.
Since 16=2 4 , this indicates that exactly 4 half-lives have elapsed.
The total time taken for this decay is given as 40 hours.
Therefore, the duration of one half-life is 40 hours/4=10 hours.
This matches the value given in Option C.
▶️ Answer/Explanation
Detailed solution:
Ionising radiation carries enough energy to remove electrons from atoms, which can damage DNA and cause cell mutations. This mutation of cells is a significant harmful effect on living organisms. Conversely, high doses of radiation can be precisely targeted to kill cancer cells, a process used in radiotherapy. In Row C, both effects are correctly identified: “cell mutation” as the hazard and “killing cancer cells” as the benefit. Other options incorrectly pair these effects or list processes like “making vitamin D” which are not associated with ionising nuclear radiation. Therefore, Option C is the correct answer.
▶️ Answer/Explanation
Detailed solution:
Option A is incorrect because the outer planets (Jupiter, Saturn, Uranus, and Neptune) are gas giants, not rocky.
Option B is incorrect as many other planets, such as Mars and Jupiter, also have moons.
Option C is correct because Pluto was reclassified as a dwarf planet in 2006.
Option D is incorrect because the Solar System contains only one star, which is the Sun.
Therefore, Option C is the only correct statement.
▶️ Answer/Explanation
Detailed solution:
The Sun’s peak radiation occurs across three main regions of the electromagnetic spectrum: ultraviolet, visible, and infrared.
In the spectrum, ultraviolet radiation has shorter wavelengths than visible light, while infrared radiation has longer wavelengths.
According to the graph, P represents the region with the shortest wavelengths, which is ultraviolet.
R represents the region with the longest wavelengths shown, which corresponds to infrared radiation.
Therefore, P is ultraviolet and R is infrared, matching Option D.
▶️ Answer/Explanation
Detailed solution:
Redshift is defined as an increase in the observed wavelength of radiation from receding galaxies .
Light from distant galaxies appears redshifted compared to light emitted on Earth .
This observation indicates that galaxies are moving away from us, providing evidence for an expanding Universe .
This expansion is a key pillar of the Big Bang Theory.
Therefore, statement C is the only correct description of redshift and its implications.