Mark Scheme

Section A — Structured Questions (54 marks)

Question 1

(a) (1 mark)

• Extension is directly proportional to weight [1]
• Accept: "extension increases linearly with weight" / "they are proportional"
• Accept: "as one doubles the other doubles"

(b) (3 marks)

• Use of F = ke (or equivalent rearrangement) [1]
• Correct substitution: k = 1.0 ÷ 0.012 (or equivalent using any data pair) [1]
• k = 83(.3) N/m [1]
• Accept 83 N/m to 84 N/m
• Award 2 marks maximum if answer not in N/m (e.g. given in N/mm)

(c) (2 marks)

• The extension is less than expected (or extension is not proportional to force) [1]
• The spring has exceeded its limit of proportionality / elastic limit [1]
• Accept: "spring has been permanently deformed" / "Hooke's law no longer applies"

(d) (2 marks)

• Use of EPE = ½ke² (or ½Fe) [1]
• 0.096 J (accept 0.095-0.097 J) [1]
• Award both marks for correct answer with no working shown
• Accept answer of 96 mJ

Question 2

(a) (3 marks)

• Correct equation selected: v² = u² + 2as [1]
• Correct substitution: 0 = 28² + 2 × a × 70 [1]
• a = -5.6 m/s² (accept -5.5 to -5.7 m/s² or 5.6 m/s² if magnitude only) [1]

(b) (2 marks)

• Use of F = ma [1]
• F = 7840 N (accept 7700-7900 N or 7.8 kN) [1]

(c) (1 mark)

• 91 m [1]
• Accept 90-92 m

(d) (3 marks)

• ABS prevents wheels locking / allows wheels to keep rotating [1]
• This maintains friction between tyres and road surface [1]
• Maximum friction / grip occurs when wheels are rotating (not sliding), giving greater braking force / shorter braking distance [1]
• Accept: "sliding friction is less than static friction"
• Accept: reference to maintaining steering control (for 3rd mark)

Question 3

(a) (1 mark)

• Variable resistor [1]
• Accept: rheostat
• Do not accept: potentiometer / dimmer switch

(b) (2 marks)

• Use of R = V/I [1]
• R = 8(.0) Ω [1]

(c) (3 marks)

• Current causes heating of the filament wire [1]
• Temperature of the filament increases [1]
• Resistance increases with temperature (for a metal conductor / filament) [1]
• Accept: reference to increased ion/atom vibrations impeding electron flow

(d) (2 marks)

• The graph would be a straight line (through the origin) [1]
• Because resistance remains constant / current is directly proportional to potential difference [1]

Question 4

(a) (2 marks)

• A large / heavy / unstable nucleus [1]
• Splits into two smaller nuclei (+ neutrons) releasing energy [1]
• Accept: "nucleus breaks apart"

(b) (1 mark)

• 3 [1]
• Accept answer shown on equation: written before the neutron symbol

(c) (2 marks)

• Neutrons released from one fission reaction [1]
• Go on to cause further fission reactions / collide with other uranium nuclei [1]

(d) (3 marks)

• Material: boron / cadmium / any neutron-absorbing material [1]
• Control rods absorb neutrons [1]
• Inserting rods further reduces the number of neutrons available, decreasing rate of fission / removing rods increases rate [1]

(e) (2 marks)

• Method: underground storage / burial in deep geological repositories / encased in glass/concrete and buried / stored in secure facilities [1]
• Problem: risk of leakage into groundwater / difficult to guarantee safety for thousands of years / finding geologically stable sites / public opposition / high cost [1]
• Accept any one sensible problem

Question 5

(a) (2 marks)

• Use of P = IV (rearranged to I = P/V) [1]
• I = 9.6 A (accept 9.5-9.7 A) [1]

(b) (2 marks)

• Use of E = mcΔθ [1]
• E = 516,600 J (accept 516,000-517,000 J or 517 kJ) [1]

(c) (3 marks)

• Energy supplied = Pt = 2200 × 195 = 429,000 J (or 429 kJ) [1]
• Efficiency = (useful energy out / total energy in) × 100 [1]
• Efficiency = 120% OR recognition that calculated value > 100% indicates an error / this is impossible [1]
• If candidate reaches >100% and states this is impossible or there's an error, award all 3 marks
• If candidate calculates 120% without comment, award 2 marks only
• Accept efficiency of 83-84% if candidate uses inverse calculation (429/517)

(d) (2 marks)

• The fuse must break the live connection to make the appliance safe [1]
• If fuse was in neutral, the appliance would still be connected to live voltage even when fuse blows / appliance could still be dangerous [1]

Question 6

(a) (2 marks)

• Velocity is a vector (has direction as well as magnitude) [1]
• The satellite's direction is constantly changing, so velocity is changing, which means it is accelerating [1]
• Accept: "acceleration is change in velocity; velocity changes because direction changes"

(b) (2 marks)

• Gravitational force / gravity / weight [1]
• Acts towards the centre of the Earth / radially inward / towards centre of orbit [1]

(c) (2 marks)

• Use of W = mg [1]
• W = 3570 N (accept 3500-3600 N or 3.57 kN) [1]

(d) (3 marks)

• Orbital period is 24 hours / 1 day [1]
• Must orbit above equator so that orbital plane contains Earth's centre (of mass) [1]
• Satellite must orbit in same direction as Earth's rotation / have same angular velocity as Earth's rotation [1]
• Accept: "must match Earth's rotation"

Section B — Extended Response (36 marks)

Question 7 (12 marks)

Levels of response marking:

Level 3 (9-12 marks): A comprehensive evaluation that addresses all aspects of the question. Energy efficiency and energy transfers are correctly described for all methods. Economic analysis includes both capital and running costs over the lifetime. Environmental factors are discussed in detail. Reliability issues are evaluated. A justified recommendation is made based on evidence presented. The answer is logically structured with correct use of physics terminology throughout.

Level 2 (5-8 marks): An adequate evaluation addressing most aspects of the question. Energy efficiency is discussed for at least two methods with some correct physics. Economic factors are considered but analysis may be incomplete. Environmental impact is mentioned. Some evaluation of options leading to a recommendation. Answer has some logical structure and mostly correct terminology.

Level 1 (1-4 marks): Limited evaluation addressing only some aspects. Basic descriptions of methods with limited physics content. Simple statements about cost or environment without detailed comparison. Recommendation may be unsupported or missing. Limited use of correct terminology.

0 marks: No relevant content.

Indicative content (any relevant points):

Energy efficiency and transfers:

• Gas boiler: 85% efficient - some energy wasted as heat to surroundings
• Electric immersion: 100% efficient at point of use BUT electricity generation typically only 35-40% efficient overall
• Solar thermal: free energy from Sun when available, variable efficiency depending on weather
• Discussion of energy transfers: chemical to thermal (gas), electrical to thermal (immersion), light/radiation to thermal (solar)

Economic factors:

• Method A: total 25-year cost = £12,000 + (25 × £18,000) = £462,000
• Method B: total 25-year cost = £8,000 + (25 × £45,000) = £1,133,000
• Method C: total 25-year cost = £45,000 + (25 × £6,000) = £195,000
• Payback period for solar: higher installation cost recovered through lower running costs
• Solar thermal is most economical over lifetime despite high initial cost

Environmental impacts:

• Gas produces CO₂ emissions contributing to climate change
• Electricity production may involve fossil fuels (depending on grid mix)
• Solar thermal: no emissions during operation, renewable energy source
• Manufacturing impacts of solar panels should be considered

Reliability:

• Gas and electric: reliable and available on demand
• Solar: dependent on weather, requires backup system
• Method C includes gas backup so maintains reliability

Justified recommendation:

• Should select Method C based on lowest lifetime cost and environmental benefits
• Or justified alternative if reliability concerns prioritised

Question 8 (12 marks)

Levels of response marking:

Level 3 (9-12 marks): A thorough discussion demonstrating clear understanding of longitudinal and transverse waves. Accurate comparison of wave types with correct reference to both experiments. Clear explanation of energy transfer without matter transfer, using particle motion. Detailed description and explanation of reflection. Critical evaluation of how well the experiments demonstrate the stated properties. Logical structure throughout with accurate scientific terminology.

Level 2 (5-8 marks): Adequate discussion showing understanding of wave types. Comparison of longitudinal and transverse waves with reference to at least one experiment. Some explanation of energy transfer. Description of reflection present but may lack full explanation. Some evaluation of the experiments. Generally logical structure with mostly accurate terminology.

Level 1 (1-4 marks): Limited discussion with basic understanding of waves. Simple descriptions of wave types with limited or no comparison. Energy transfer mentioned but not explained. Limited reference to reflection. Little or no evaluation of experiments. Basic structure and terminology.

0 marks: No relevant content.

Indicative content (any relevant points):

Comparing longitudinal and transverse:

• Experiment 1 shows longitudinal waves: oscillations parallel to direction of energy transfer
• Experiment 2 shows transverse waves: oscillations perpendicular to direction of energy transfer
• Slinky coils move back and forth along direction of spring (compression and rarefaction)
• Water surface moves up and down, wavefronts move horizontally across tank

Energy transfer without matter transfer:

• In slinky: coils oscillate about fixed positions, don't travel along the spring, but energy pulse travels along
• In water: water molecules move in circles/up and down, don't travel with wave, but energy spreads outward
• Individual particles only transfer energy to neighboring particles
• This demonstrates energy transfer without net movement of medium

Reflection of waves:

• Experiment 2 shows reflection: waves bounce off barrier
• Angle of incidence = angle of reflection
• Wavefronts change direction but wavelength and frequency remain constant
• Demonstrates wave property independent of wave type

Evaluation of experiments:

• Strengths: clearly demonstrate difference between wave types, easy to observe, reflection clearly visible in ripple tank
• Limitations: Experiment 1 doesn't show reflection of longitudinal waves, slinky is simplified 1D model
• Ripple tank is 2D surface waves (not pure transverse - water particles move in circles)
• Both successfully show energy transfer without matter transfer
• Statement is largely supported but experiments have limitations

Conclusion:

• Experiments do support main claims about wave properties
• But water waves are more complex than simple transverse waves
• Additional experiments would strengthen demonstration

Question 9 (12 marks)

Levels of response marking:

Level 3 (9-12 marks): A thorough and balanced evaluation of the claim. Energy transfers and efficiency correctly explained for both vehicle types including full fuel cycle. Electricity generation methods and their impacts are discussed in detail. Lifecycle analysis including manufacture and disposal is comprehensive. Context-dependent nature of conclusion is clearly explained. A justified, nuanced conclusion is reached. Logical structure throughout with accurate physics terminology.

Level 2 (5-8 marks): Adequate evaluation of the claim. Energy transfers and efficiency discussed for both vehicles. Some consideration of electricity generation sources. Lifecycle factors mentioned but discussion may be incomplete. Some awareness that context affects conclusion. A conclusion is reached with some justification. Generally logical structure with mostly accurate terminology.

Level 1 (1-4 marks): Limited evaluation showing basic understanding. Simple comparison of electric vs petrol cars. Energy efficiency mentioned but not explained. Limited consideration of wider factors. Conclusion may be unsupported or too simplistic. Basic structure and terminology.

0 marks: No relevant content.

Indicative content (any relevant points):

Energy transfers and efficiency:

• Petrol car: chemical energy → thermal energy → kinetic energy (via internal combustion engine)
• Petrol engines typically 20-30% efficient, most energy wasted as heat
• Electric car: chemical energy (battery) → electrical energy → kinetic energy (via motor)
• Electric motors 85-90% efficient at point of use
• BUT must consider efficiency of electricity generation (35-40% for fossil fuels)
• Overall efficiency chain for EV depends on generation method

Electricity generation sources:

• Renewable sources (wind, solar, hydro): very low carbon emissions, makes EVs much cleaner
• Coal-fired power: high carbon emissions, reduces benefit of EVs
• Study shows 70% reduction (renewable) vs 20% reduction (coal-dependent)
• Grid mix varies by country and is changing over time towards renewables
• Future trends: as grid decarbonises, EVs become progressively cleaner

Lifecycle considerations:

• Manufacturing: battery production is energy-intensive, mining impacts, but petrol cars also have manufacturing emissions
• Use phase: significant difference depending on electricity source
• Disposal: battery recycling technology improving, lithium recovery possible
• 8-10 year battery life is a concern but improving with technology
• Must consider total lifecycle not just use phase

Context dependency:

• Where electricity is clean: strong environmental case for EVs
• Where electricity is from coal: benefits much smaller but still positive
• Battery technology and recycling improving
• Grid decarbonisation means future benefits will increase

Justified conclusion:

• Overall environmental benefit depends on electricity source
• In most contexts EVs are better than petrol cars over lifetime
• Benefits will increase as grids decarbonise
• Should be promoted but alongside investment in renewable energy
• Not a complete solution on their own - need sustainable electricity generation
• Accept alternative justified positions that consider the evidence

Sample Answers with Examiner Commentary

Question 7 — Sample Answers

Grade 9 (top of Higher) answer

To evaluate these three methods, I need to consider energy efficiency, costs over the full lifetime, environmental impact, and reliability.

Energy efficiency: The electric immersion heater is 100% efficient at converting electrical energy to thermal energy, but this doesn't tell the whole story. Electricity generation in power stations is only about 35-40% efficient overall, so the overall efficiency is much lower. The gas boiler is 85% efficient, which means 15% of the chemical energy in the gas is wasted, mostly as heat to surroundings. Solar thermal panels convert radiation from the Sun directly to thermal energy in the water with no fuel cost, though efficiency varies with weather conditions. When the Sun isn't available, the gas backup operates.

Economic analysis: Over 25 years, Method A costs £12,000 + (25 × £18,000) = £462,000 total. Method B costs £8,000 + (25 × £45,000) = £1,133,000 total. Method C costs £45,000 + (25 × £6,000) = £195,000 total. Although Method C has the highest installation cost, it has by far the lowest total cost over the building's lifetime, saving over £250,000 compared to gas and nearly £940,000 compared to electric.

Environmental impacts: Burning natural gas releases carbon dioxide, a greenhouse gas contributing to climate change. The electricity method also has environmental impact because most electricity is generated by burning fossil fuels. Solar thermal uses renewable energy from the Sun, producing no emissions during operation and no fuel is consumed. However, manufacturing solar panels does have some environmental cost. Overall, Method C has the lowest environmental impact.

Reliability: Both gas and electricity supplies are available on demand 24/7, making Methods A and B very reliable. Solar thermal depends on weather and time of day, but Method C includes a gas backup system which ensures hot water is always available even during periods of low sunshine. This makes it reliable while still gaining benefits from solar energy when available.

I would recommend Method C (solar thermal with gas backup). It has the lowest lifetime cost, saving the authority substantial money that could be invested elsewhere. It has the smallest environmental impact by using renewable energy. The inclusion of the gas backup system means reliability is maintained. The higher upfront cost is justified by the long 25-year operational period and would be recovered within just a few years through reduced running costs.

Mark: 12/12

Examiner commentary: This response demonstrates comprehensive evaluation across all required areas. The physics of energy efficiency is correctly explained with recognition that overall efficiency must consider the full energy chain. Economic analysis is complete with accurate calculations and clear comparison. Environmental factors are well-explained with reference to greenhouse gases and renewable energy. Reliability concerns are addressed and the backup system is discussed. The recommendation is fully justified with multiple supporting points. Clear structure and accurate physics terminology throughout place this firmly in Level 3, achieving full marks.

Grade 6 (solid pass) answer

The three methods all heat water but have different efficiencies and costs.

Method A uses a gas boiler which is 85% efficient. This means 85% of the energy is transferred usefully and 15% is wasted. Method B uses electric heaters which are 100% efficient so no energy is wasted. Method C uses solar panels which use free energy from the Sun.

For costs, the gas boiler costs £12,000 to install and £18,000 per year to run. Over 25 years this is £12,000 + £450,000 = £462,000. The electric heaters cost £8,000 to install and £45,000 per year, which is £8,000 + £1,125,000 = £1,133,000 over 25 years. The solar panels cost £45,000 to install but only £6,000 per year to run, which is £45,000 + £150,000 = £195,000. Solar is cheapest overall even though it costs more to install.

For the environment, gas produces pollution and carbon dioxide. Electricity might also cause pollution depending on where it comes from. Solar panels don't produce pollution because they use the Sun's energy which is renewable.

The problem with solar is that it might not work when it's cloudy or at night, but this system has a gas backup so there will always be hot water.

I would recommend Method C because it is cheapest over 25 years and is best for the environment. It will save lots of money compared to the other methods.

Mark: 7/12

Examiner commentary: This response achieves Level 2 (high). The candidate correctly calculates lifetime costs and makes valid comparisons. Energy efficiency is discussed, though the claim that electric heaters waste no energy misses the point about generation efficiency. Environmental impact is mentioned but lacks detail about greenhouse effect or climate change. Reliability is briefly addressed. The recommendation is present and has some justification. To reach Level 3, the answer needed more sophisticated physics (e.g., energy transfer chains, overall efficiency of electricity generation), more detailed environmental discussion, and fuller evaluation of all factors.

Grade 3 (near miss) answer

All three methods can heat water for the leisure centre.

Method A uses gas which costs £18,000 per year. Method B uses electricity which costs £45,000 per year. Method C uses solar panels which cost £6,000 per year. The solar panels are cheapest to run so they are the best option.

Gas boilers cause pollution which is bad for the environment. Electric heaters are better because electricity is clean and doesn't cause pollution. Solar panels are also clean because they use energy from the Sun.

The electric heaters are 100% efficient which means they don't waste any energy, so they are more efficient than the gas boiler which is only 85% efficient. This means electric is better than gas.

I would choose the electric heaters because they are 100% efficient and don't cause pollution. Even though they cost more to run, they are better for the environment and don't waste energy like gas boilers do.

Mark: 3/12

Examiner commentary: This response falls into Level 1. The candidate makes some relevant observations about running costs but ignores installation costs and doesn't calculate total lifetime costs. A common misconception is evident: that electricity is "clean" and causes no pollution, failing to recognise that electricity generation often involves burning fossil fuels. The claim that electric is more efficient misses the crucial point about overall system efficiency. Environmental discussion is superficial and contains errors. The recommendation contradicts the economic evidence presented and is poorly justified. To improve, the candidate needs to: calculate total lifetime costs including installation, understand that electricity must be generated (often from fossil fuels), explain energy efficiency across the whole system, and provide a properly justified recommendation based on evidence.

Question 8 — Sample Answers

Grade 9 (top of Higher) answer

The teacher's statement is largely supported by these experiments, though there are some limitations.

Experiment 1 demonstrates longitudinal waves. In a longitudinal wave, the oscillations of particles are parallel to the direction of energy transfer. When the teacher moves the end of the slinky back and forth, compressions and rarefactions travel along the spring. The coils of the slinky oscillate backwards and forwards along the axis of the spring, but each coil only moves a small distance around its equilibrium position. The energy pulse travels along the whole length of the spring. This shows that energy is transferred along the spring without the matter (the coils) traveling along – they just vibrate in place while the energy moves through them.

Experiment 2 demonstrates transverse waves. In transverse waves, the oscillations are perpendicular to the direction of energy transfer. The water surface moves up and down while the wavefronts spread outwards horizontally across the tank. Each water particle oscillates vertically (actually in small circular paths) but stays in approximately the same horizontal position, while the wave pattern moves across the tank. Again, this shows energy transfer without matter transfer – the water doesn't flow across the tank, only the energy does.

These experiments clearly demonstrate the key difference between longitudinal and transverse waves: the orientation of oscillations relative to energy transfer direction. Both successfully show that waves transfer energy without transferring matter, because in both cases the medium (slinky coils or water) oscillates locally while the wave pattern and energy travel through the medium.

Experiment 2 also demonstrates reflection. When the circular wavefronts reach the flat barrier, they reflect following the law of reflection: the angle of incidence equals the angle of reflection, measured from the normal to the barrier. The wavelength and frequency remain constant during reflection; only the direction changes. This is an important wave property. However, Experiment 1 as described doesn't show reflection of longitudinal waves, which is a limitation – sound waves do reflect (echoes), but this isn't demonstrated by the slinky experiment.

There are some limitations to these experiments. Water waves are actually more complex than simple transverse waves – water particles move in circular or elliptical paths, not just up and down. They're sometimes described as having both longitudinal and transverse components. The slinky experiment is simplified and one-dimensional. Additionally, neither experiment clearly demonstrates other wave properties like refraction, diffraction or interference, though the ripple tank could be modified to show these.

Overall, the experiments do effectively support the teacher's statement. They clearly demonstrate the fundamental distinction between longitudinal and transverse waves, they both show energy transfer without matter transfer through the oscillation of particles about fixed positions, and reflection is demonstrated for transverse waves. While there are some limitations, these are reasonable demonstrations of key wave properties suitable for showing the principles involved.

Mark: 12/12

Examiner commentary: This is an exemplary Level 3 response demonstrating sophisticated understanding of wave properties. The candidate provides detailed comparison of longitudinal and transverse waves with accurate descriptions of particle motion in both experiments. Energy transfer without matter transfer is thoroughly explained with clear reference to local oscillations versus wave propagation. Reflection is described accurately with reference to the law of reflection and constancy of wavelength/frequency. Critically, the response includes excellent evaluation, noting limitations such as the absence of longitudinal wave reflection in Experiment 1 and the complexity of water waves. The conclusion appropriately judges that the experiments largely support the statement despite minor limitations. Excellent use of technical terminology and logical structure throughout.

Grade 6 (solid pass) answer

The two experiments show different types of waves.

In Experiment 1, the slinky shows longitudinal waves. This is where the vibrations are in the same direction as the wave travels. When the teacher moves the slinky back and forward, compressions and rarefactions move along the spring. The coils vibrate backwards and forwards but they don't travel along the spring, only the wave does. This shows that energy moves along the spring without the matter (coils) moving along.

In Experiment 2, the ripple tank shows transverse waves. This is where the vibrations are at right angles to the direction the wave travels. The water moves up and down but the waves spread out horizontally. The water doesn't move across the tank, only the wave pattern does. This also shows energy transfer without matter transfer.

These experiments show the difference between longitudinal and transverse waves clearly. In longitudinal the vibrations are parallel to the energy transfer, in transverse they are perpendicular.

The ripple tank experiment shows reflection when the waves bounce off the barrier. When waves reflect, the angle they come in at equals the angle they bounce off at. The waves change direction but the wavelength stays the same.

The experiments are good for demonstrating wave properties. You can clearly see the difference between the two types of waves and how waves transfer energy. The ripple tank clearly shows reflection. However, the slinky experiment doesn't show reflection of longitudinal waves, which is a weakness. Sound waves can reflect to make echoes, so it would be better to demonstrate this as well.

Overall the experiments do support the teacher's statement because they show the different types of waves and energy transfer without matter transfer, and one shows reflection.

Mark: 7/12

Examiner commentary: This is a secure Level 2 response. The candidate correctly identifies and describes both wave types with accurate reference to particle motion direction. Energy transfer without matter transfer is explained adequately for both experiments. Reflection is described with the law of reflection correctly stated. The response includes some evaluation, noting that longitudinal wave reflection isn't demonstrated. However, to reach Level 3, the answer needed: more detailed explanation of how particle oscillation leads to energy transfer, more sophisticated physics terminology, deeper discussion of wave properties, and more thorough evaluation. The conclusion is present but could be more developed with consideration of the experiments' effectiveness.

Grade 3 (near miss) answer

Experiment 1 uses a slinky spring and shows longitudinal waves. Longitudinal waves are waves that go backwards and forwards. The slinky moves back and forth and makes waves go along the spring. This shows that energy moves along the spring.

Experiment 2 uses a ripple tank with water and shows transverse waves. Transverse waves go up and down. The water goes up and down and makes circular waves that spread out. This shows energy moving across the water.

The difference between them is that longitudinal go backwards and forwards and transverse go up and down.

The ripple tank shows reflection when the waves hit the barrier and bounce off. Reflection is when waves bounce off things.

Waves transfer energy but not matter because the particles vibrate but don't move along. The slinky coils stay in the same place and so does the water.

The experiments show what the teacher said because they demonstrate the two types of waves and show energy transfer and show reflection. They are good experiments for showing waves.

Mark: 4/12

Examiner commentary: This response just reaches the bottom of Level 2. The candidate identifies both wave types but descriptions are imprecise (longitudinal waves don't "go backwards and forwards" – the particles do). The key concept of oscillation direction relative to energy transfer direction is poorly explained. Energy transfer without matter transfer is mentioned but not fully explained – why don't particles move along while energy does? Reflection is identified but not explained beyond "bouncing." The evaluation is minimal and uncritical. To improve, the candidate should: clearly state that in longitudinal waves particles oscillate parallel to energy direction while in transverse they oscillate perpendicular; explain that particles transfer energy to neighbors through oscillation; describe the law of reflection; and provide critical evaluation of the experiments' strengths and limitations. The answer needs more physics content and more precise scientific terminology.