Work and Energy — Free IB MYP4 Physics Questions

Work and Energy — Free MYP4 Physics Practice Questions

1QuestionRadiation and Emission of Infrared EnergyConcept Practice

2 marks~3 minCriterion D

Infrared thermography is used in medical imaging to detect inflammation. A thermographic camera detects infrared radiation emitted from the skin's surface and maps temperature variations across the body. Doctors use these thermal maps to identify regions of elevated temperature, which may indicate underlying inflammation, without any physical contact with the patient.

Explain one benefit of using infrared thermography for the early detection of inflammation. [1]

Explain one limitation of infrared thermography as a diagnostic tool. [1]

Solutions

2QuestionInsulation Techniques and Practical ApplicationsConcept Practice

1 mark~2 minCriterion A

A thermos flask keeps hot coffee warm by using a vacuum between its double glass walls.

Identify the method of heat transfer that cannot occur through the vacuum, and explain why the vacuum prevents it. [1]

Solutions

3QuestionDesigning Energy-Efficient SystemsConcept Practice

2 marks~3 minCriterion D

A school replaces 200 incandescent bulbs (60 W each) with LED bulbs (9 W each). Both types produce equivalent light output. The school operates the lights for 8 hours per day, 200 days per year. The local electricity grid is powered predominantly by coal-fired power stations.

Explain one way in which this transition reduces the school's energy consumption. [1]

Discuss one environmental benefit of this reduced energy consumption, linking it to the use of coal-fired power generation. [1]

Solutions

4QuestionEnergy Changes in Light Bulbs Motors and ToastersConcept Practice

2 marks~3 minCriterion A

A 60 W incandescent light bulb converts electrical energy in its tungsten filament, reaching temperatures above 2500 °C. Only about 5% of the input energy is converted to visible light; the remainder is lost to the surroundings.

Identify the two primary forms of energy emitted by the filament when the bulb is switched on. [1]

Explain why the filament of an incandescent bulb is considered inefficient as a lighting device, referring to the energy data given. [1]

Solutions

5QuestionEnergy Flow in SystemsConcept Practice

2 marks~3 minCriterion A

The Hoover Dam on the Colorado River stands 221 m above its turbine inlets. Water released from the reservoir accelerates downward through penstocks before striking the turbine blades.

Describe the primary energy transformation that occurs as the water falls from the reservoir surface to the turbine inlet. [2]

Solutions

6QuestionEfficiency = Useful Output Total Input x 100Concept Practice

2 marks~3 minCriterion A

A motor lifts a 2 kg mass through a height of 1 m. The energy flow diagram below shows the electrical energy supplied to the motor, the gravitational potential energy gained by the mass, and the thermal energy lost as heat.

State the formula for efficiency, identifying each term in the equation with reference to this motor system. [2]

Solutions

7QuestionEnergy Resource Comparison ChartConcept Practice

1 mark~2 minCriterion A

The diagram shows a hydroelectric dam with water stored at height

h = 45\ \text{m}

above the turbines. The reservoir holds

2.4 \times 10^9\ \text{kg}

of water.

Identify the type of energy possessed by the water stored in the reservoir. [1]

Solutions

8QuestionTypes of Renewable Energy SourcesConcept Practice

2 marks~3 minCriterion D

In many remote villages across sub-Saharan Africa, communities rely on solar photovoltaic (PV) systems as their primary electricity source.

Outline one way in which a solar PV system generates and delivers electrical energy to village homes. [1]

Explain one specific impact this electricity supply has on the daily lives of people in such a village. [1]

Solutions

9QuestionHydraulic SystemsConcept Practice

2 marks~3 minCriterion A

A hydraulic lift is used in a car repair workshop to raise vehicles. A simplified diagram of the system is provided, showing two pistons connected by a sealed chamber. The components are unlabelled.

Identify the following components by writing the correct term next to the arrow pointing to each part:

Input piston [1]

Output piston [1]

Solutions

10QuestionPressure in Liquids / GasesConcept Practice

2 marks~3 minCriterion A

A car mechanic uses a hydraulic lift to raise a car. The input piston has an area of

0.005 \ \text{m}^2

and the output piston has an area of

0.10 \ \text{m}^2

. The mechanic applies a force of

250 \ \text{N}

to the input piston.

State Pascal's principle. [1]

Calculate the force exerted on the output piston. [1]

Solutions

11QuestionComparing All Three Modes of Heat TransferAssessment Practice

13 marks~20 minCriterion C

A student investigates heat transfer from a heat lamp. Three identical thermometers are placed

0.50 \, \text{m}

from the lamp, each starting at

20.0 \, \text{°C}

.

- Thermometer A: wrapped in black paper
- Thermometer B: wrapped in white paper
- Thermometer C: inside a vacuum flask with a transparent front face directed at the lamp

Temperatures are recorded every minute for 10 minutes. The graph below shows temperature against time for all three thermometers.

Describe the temperature trends shown by thermometers A, B, and C over the 10-minute period. In your answer, compare the rates of temperature increase, identify which thermometer reaches the highest final temperature, and use values from the graph to support your description. [3]

Explain the differences in temperature change among the three thermometers. In your answer, refer to the absorption of infrared radiation by black and white surfaces, and explain how the vacuum flask affects heat transfer by conduction and convection. [4]

Evaluate the reliability of this investigation by identifying one strength of the experimental design, two distinct sources of uncertainty, and one improvement that would increase reliability. [4]

The student concludes: "Black surfaces are always the best choice for reducing heat transfer." Discuss whether the evidence from this investigation fully supports this conclusion. [2]

Solutions

12QuestionInsulation Techniques and Practical ApplicationsAssessment Practice

12 marks~18 minCriterion C

A student investigates heat loss from containers of hot water. Three identical containers are filled with equal volumes of water at

80\ °C

. Container A is wrapped with fibreglass insulation, Container B with cellulose insulation, and Container C is left uninsulated. Temperature is recorded every 5 minutes for 30 minutes. The graph below shows the cooling curves for all three containers.

Identify which container lost the least thermal energy over 30 minutes. Justify your answer using temperature data from the graph. [3]

Explain how fibreglass and cellulose insulation reduce heat loss by conduction, convection, and radiation. [6]

Evaluate two limitations of this experimental setup and, for each, propose a specific improvement that would increase the reliability of the results. [3]

Solutions

13QuestionConvection in Liquids and GasesAssessment Practice

9 marks~14 minCriterion D

A town is evaluating a geothermal heating system. Cold water is pumped deep underground, heated by convection currents driven by geothermal energy, and returned to the surface through a distribution network. The system would replace the town's existing gas-fired boilers, which currently emit

\text{CO}_2

\text{SO}_x

, and

\text{NO}_x

. Multiple deep-well injection sites are required, and some drilling locations overlap with residential land. The geothermal resource is finite if extraction exceeds natural recharge rates.

Explain two environmental benefits of replacing gas-fired boilers with this geothermal system. [2]

Analyse the environmental risks introduced by the geothermal system, including induced seismicity, land use, and resource sustainability. [4]

Evaluate whether the geothermal system should be implemented, considering the ethical issues of community displacement and equitable access to heating, alongside the geographical and economic limitations of the technology. [3]

Solutions

14QuestionRadiation and Emission of Infrared EnergyAssessment Practice

3 marks~5 minCriterion A

The graph below shows the infrared radiation emitted by three materials (A, B, C) across a temperature range of 0 °C to 100 °C. Material A produces the steepest curve, Material B a moderate curve, and Material C the shallowest curve. All three curves slope upward with increasing temperature.

Explain why the infrared radiation emitted by a material increases as its temperature rises. [1]

Explain why Materials A, B, and C emit different amounts of infrared radiation at the same temperature. [1]

Material A emits significantly more radiation than Material C at every temperature shown. Analyse what this difference reveals about the surfaces of the two materials and how this could be exploited in a real-world thermal engineering application. [1]

Solutions

15QuestionInsulation Techniques and Practical ApplicationsAssessment Practice

12 marks~18 minCriterion B

A construction company tests insulation materials for model houses. Each identical model house is insulated with a different material and thickness. The interior is maintained at

25\ ^\circ\text{C}

; the exterior is held at

5\ ^\circ\text{C}

. The rate of heat loss (W) is recorded for each combination of thermal conductivity

\lambda

(W/mK) and insulation thickness

d

(m). Results are shown in the graph.

Deduce the relationship between thermal conductivity, insulation thickness, and rate of heat loss, using evidence from the graph. [4]

A new insulation material has

\lambda = 0.035\ \text{W/mK}

and

d = 0.12\ \text{m}

. Using the relationship identified in part (a), calculate the predicted rate of heat loss and justify whether this material performs better or worse than a material with

\lambda = 0.050\ \text{W/mK}

and

d = 0.10\ \text{m}

. [5]

Analyse two limitations of this model experiment that reduce its validity when predicting heat loss in a full-sized house. [3]

Solutions

16QuestionConvection in Liquids and GasesAssessment Practice

13 marks~20 minCriterion B

A rectangular water tank (length 30 cm, width 15 cm, height 20 cm) is used to investigate how the temperature gradient affects the speed of convection currents. A lamp heats one end of the tank; dye is used to visualise water movement. The temperature gradient is defined as

\frac{\Delta T}{\Delta x}

, where

\Delta T

is the temperature difference (°C) and

\Delta x

is the distance between measurement points (cm).

Data collected at fixed

\Delta x = 10

cm:

$\Delta T$ (°C)	5	10	15
Convection current speed $v$ (cm/s)	0.5	1.0	1.5

Describe the procedure you would follow to set up the tank, create at least three different temperature gradients, and measure the speed of convection currents using dye. Include one relevant safety precaution. [4]

Construct a results table for this experiment. The table must include columns for

\Delta T

(°C),

\Delta x

(cm),

\frac{\Delta T}{\Delta x}

(°C/cm), and

v

(cm/s). Explain how you would use the dye to calculate

v

. [3]

Using the data provided, calculate the temperature gradient for each trial, identify the relationship between

\frac{\Delta T}{\Delta x}

and

v

, and evaluate whether this relationship is physically reasonable for convection in water. [6]

---

Solutions

17QuestionEnergy Changes in Light Bulbs Motors and ToastersAssessment Practice

10 marks~15 minCriterion D

A household uses two identical lamps: one fitted with a 60 W incandescent bulb (efficiency 8%) and one with a 10 W LED bulb producing the same luminous output. Both operate for 6 hours per day. Electricity costs 0.15 dollars per kWh. The incandescent bulb lasts 1 000 hours; the LED lasts 15 000 hours.

Explain the energy transformations occurring in each bulb as electrical energy is supplied. [2]

Calculate the useful power output (light) and the power dissipated as heat for each bulb. [3]

Evaluate whether replacing the incandescent bulb with the LED bulb is justified, considering annual electricity costs, bulb-replacement costs, and one environmental impact. [5]

Solutions

18QuestionIdentifying Input and Output Energy FormsAssessment Practice

12 marks~18 minCriterion B

A toaster's heating element converts electrical energy into thermal energy. The table below shows measurements taken at three power settings.

Toaster setting	Low, Medium, High
Electrical energy input (J)	500, 750, 1000
Thermal energy output (J)	400, 600, 700

The cost of electricity is 0.20 dollars per 1000 J.

\text{Efficiency} = \frac{\text{useful energy output}}{\text{total energy input}} \times 100

Calculate the efficiency of the toaster at each of the three settings. [3]

Deduce what the data suggest about how energy losses change as the toaster setting increases. [3]

Analyse why operating the toaster at the High setting is less energy-efficient than at the Low setting, identifying the dominant form of energy loss and explaining the physical mechanism by which that loss increases at higher power. [6]

Solutions

19QuestionEnergy Changes in Light Bulbs Motors and ToastersAssessment Practice

3 marks~5 minCriterion A

When an incandescent light bulb is switched on, the tungsten filament starts at room temperature. The graph shows electrical power input surging immediately after switch-on, then falling to a constant steady-state value over the first few seconds.

Explain why the power input is highest at the moment the bulb is switched on. [1]

Explain how the energy transformation occurring in the filament causes the power input to decrease during the first few seconds. [1]

Analyse the steady-state condition reached by the filament, identifying the energy transformations involved and explaining why power input no longer changes. [1]

Solutions

20QuestionIdentifying Input and Output Energy FormsAssessment Practice

2 marks~3 minCriterion C

A hairdryer draws

1500 \, \text{J}

of electrical energy per second. Its heating element dissipates

1200 \, \text{J/s}

as thermal energy; the remaining input powers the fan motor.

Calculate the power delivered to the fan motor as kinetic energy of the air. [1]

A student claims the hairdryer operates at

100\%

efficiency because all

1500 \, \text{J/s}

of input is accounted for as thermal and kinetic energy output. Explain why this claim is incorrect, referring to the second law of thermodynamics. [1]

Solutions

21QuestionBattery to Mechanical Energy ConversionAssessment Practice

12 marks~18 minCriterion D

Electric vehicles (EVs) convert chemical energy stored in a battery into kinetic energy during acceleration and gravitational potential energy when climbing hills. This conversion is never perfectly efficient. A typical EV motor operates at around 90% efficiency, yet real-world range is significantly lower than laboratory predictions, particularly in hilly or mountainous terrain and in cold weather conditions.

Identify and explain two factors that reduce the efficiency of energy conversion from the battery to the wheels. [2]

Explain how regenerative braking recovers energy that would otherwise be lost, and describe where that energy goes. [2]

Analyse how two battery limitations combine to reduce the effective range of an EV driven repeatedly over hilly terrain in cold weather. [4]

Evaluate whether advances in battery energy density and thermal management are sufficient to make EVs fully practical for drivers in mountainous regions. [4]

Solutions

22QuestionIdentifying Input and Output Energy FormsAssessment Practice

3 marks~5 minCriterion C

A loudspeaker is supplied with electrical energy. The graph below shows sound energy output (J) plotted against electrical energy input (J) for this loudspeaker. The relationship is linear, and the line of best fit does not pass through the origin — the sound energy output is always less than the electrical energy input.

State the primary energy transformation occurring in the loudspeaker. [1]

Explain why the sound energy output is always less than the electrical energy input. [1]

Analyse how the graph could be used to compare the efficiency of two different loudspeakers, and explain what a steeper gradient would indicate about energy losses. [1]

Solutions

23QuestionDifferent Forms of Energy Kinetic Potential Thermal etcAssessment Practice

3 marks~5 minCriterion A

A roller coaster car of mass 800 kg starts from rest at point A, height 40 m above the ground. It descends to point B at ground level, then rises to point C at height 25 m. Assume no energy is lost to friction.

Calculate the gravitational potential energy of the car at point A. Use

g = 10 \text{ m s}^{-2}

. [1]

Explain how kinetic energy and gravitational potential energy change as the car moves from A to B to C. [1]

Point C is lower than point A. Analyse what this difference in height tells us about the total mechanical energy of the car in a real roller coaster, where friction acts. [1]

Solutions

24QuestionUseful vs Wasted Energy and Sankey DiagramsAssessment Practice

10 marks~15 minCriterion D

A small community relies on a single wind turbine for its electricity. The turbine converts the kinetic energy of wind into electrical energy, but power output varies with wind speed. A Sankey diagram for the turbine shows that for every 1000 J of wind kinetic energy input, 350 J is converted to useful electrical energy.

Identify two forms of wasted energy in the wind turbine system. [2]

Using the Sankey diagram data, explain how the principle of conservation of energy applies to this turbine, and calculate the percentage of energy that is wasted. [4]

Evaluate the suitability of this wind turbine as the community's sole energy source, considering both its efficiency and the consistency of its power supply. [4]

Solutions

25QuestionLaw of Conservation of EnergyAssessment Practice

6 marks~9 minCriterion A

A simple pendulum is released from rest at point A, its highest point. It swings down through point B, its lowest point, and continues up to point C, its highest point on the opposite side. Assume air resistance and friction are negligible.

State the energy stored by the pendulum at point A and explain why its kinetic energy is zero at this point. [2]

Explain the energy transformations that occur as the pendulum moves from A to B to C. [2]

A student claims that the pendulum will rise to exactly the same height at C as at A. Evaluate this claim using the law of conservation of energy. [2]

Solutions

26QuestionDifferent Forms of Energy Kinetic Potential Thermal etcAssessment Practice

12 marks~18 minCriterion C

A pendulum bob of mass 0.20 kg is released from a height of 0.45 m above its lowest point. A motion sensor records position and velocity every 0.05 s over one complete swing. Students calculate

E_p = mgh

and

E_k = \frac{1}{2}mv^2

at each instant and plot

E_p

E_k

, and total mechanical energy

E_T = E_p + E_k

against time. The graph shows

E_p

and

E_k

varying smoothly in opposition, while

E_T

decreases gradually from 0.88 J to 0.79 J over the swing.

Describe the energy transformations that occur during one complete swing of the pendulum. [3]

Analyse the graph to determine whether the data supports the principle of conservation of energy. [4]

Evaluate the experimental design, identifying limitations and suggesting improvements that would better validate the energy conservation model. [5]

Solutions

27QuestionUseful vs Wasted Energy and Sankey DiagramsAssessment Practice

2 marks~3 minCriterion D

Electric cars convert stored electrical energy to kinetic energy more efficiently than internal combustion engine (ICE) vehicles, which waste a significant proportion of fuel energy as heat and sound.

Explain one way this increased efficiency can positively impact society. [2]

Solutions

28QuestionDifferent Forms of Energy Kinetic Potential Thermal etcAssessment Practice

12 marks~18 minCriterion D

A coastal town is evaluating a proposal to build an offshore wind farm. Each turbine has a rotor swept area of 8 000 m², and at a wind speed of 12 m/s the air passing through one rotor each second has a mass of 96 000 kg. The turbines replace a coal-fired power station that burns chemical energy stored in fossil fuels.

Explain the sequence of energy transformations that occurs as wind drives a turbine to produce electricity, and calculate the maximum kinetic energy available per second from one rotor at 12 m/s. [4]

Analyse two environmental drawbacks of the wind farm, linking each drawback to a specific physical or ecological mechanism. [4]

Evaluate whether the wind farm is a sustainable and ethical solution for the town, weighing the energy and environmental evidence from parts (a) and (b) against each other. [4]

Solutions

29QuestionEnergy Flow in SystemsAssessment Practice

12 marks~18 minCriterion B

A coal-fired power plant burns coal to generate electrical energy. Energy is lost as heat during the process. The graph below shows electrical energy output against energy input over one year.

Energy Input (

\times 10^9

J): 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Electrical Energy Output (

\times 10^9

J): 0, 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, 3.6, 4.0

State the formula for efficiency. [1]

Use the graph to calculate the efficiency of the power plant at an energy input of

6 \times 10^9

J. Show your working. [3]

The plant operates at a higher load, with an energy input of

9 \times 10^9

J. Calculate the heat energy lost at this input and deduce whether the fraction of energy lost has changed compared to your result in part (b). [4]

Analyse the graph to evaluate whether the efficiency of the power plant is constant across all operating levels. Justify your conclusion using at least two data points not used in parts (b) or (c). [4]

Solutions

30QuestionEfficiency = Useful Output Total Input x 100Assessment Practice

12 marks~18 minCriterion C

A student uses a pulley system to lift a heavy box. She records the input work (work done pulling the rope) and the output work (work done lifting the box) across five trials. The results are shown on the graph below.

Input Work (J)	100	150	200	250	300
Output Work (J)	72	118	162	208	240

The student claims the pulley system is approximately 80% efficient across all trials.

Calculate the efficiency for each of the five trials. [4]

Analyse the student's claim that the system is approximately 80% efficient across all trials, using your results from (a). [3]

Evaluate whether friction between the rope and pulley wheel or the weight of the rope itself is the more significant source of energy loss in this system. Justify your reasoning. [3]

Discuss ONE limitation of using this laboratory setup to determine the true efficiency of the pulley system in a real-world application. [2]

Solutions

31QuestionEfficiency = Useful Output Total Input x 100Assessment Practice

6 marks~9 minCriterion D

A school is evaluating a rooftop solar panel installation to reduce energy costs. The panels have a stated efficiency of 20%. On a typical school day, the panels receive 50 kWh of solar energy.

Calculate the electrical energy output of the panels for that day. [1]

Explain why a 20% efficiency rating means the school cannot rely solely on solar panels to meet its energy needs throughout the year, particularly in a region with variable weather. [2]

Evaluate the ethical implications of investing in solar panels that convert only 20% of incident solar energy, considering both the environmental costs of manufacturing and disposal and the long-term benefits of clean energy generation. [3]

Solutions

32QuestionCalculating Power and Energy Transfer RateAssessment Practice

5 marks~8 minCriterion B

A cyclist travels along a flat, horizontal road. The graph below shows the cyclist's power output

P

plotted against velocity

v

. Assume all power output is used to overcome resistive forces.

From the graph, determine the cyclist's power output at

v = 6\ \text{m/s}

. [1]

Using your answer from part (a), calculate the magnitude of the resistive force acting on the cyclist at

v = 6\ \text{m/s}

. [2]

The graph shows a linear relationship between

P

and

v

, passing through the origin. Analyse what this relationship reveals about how the resistive force changes as the cyclist's velocity increases, and justify your conclusion using your result from part (b). [2]

Solutions

33QuestionUnits Joules Watts and Their ConversionsAssessment Practice

12 marks~18 minCriterion A

A student investigates how the bounce height of a tennis ball depends on its drop height. The table below shows the data collected.

Drop height $h_d$ (m)	1.00	1.50	2.00	2.50	3.00
Bounce height $h_b$ (m)	0.70	1.05	1.40	1.75	2.10

Construct a graph of bounce height against drop height, plotting all five data points and drawing a line of best fit. [2]

Deduce the relationship between

h_b

and

h_d

, expressing your answer as an equation. [3]

Justify a prediction for the bounce height when the ball is dropped from 3.50 m. [2]

In a real experiment the ball bounces several times, each time reaching a lower height, until it stops. Analyse the energy transformations occurring during this process and explain why the ball eventually stops bouncing. [5]

Solutions

34QuestionDefinition and Formula for Work DoneAssessment Practice

5 marks~8 minCriterion C

A student pulls a wooden block at constant speed across a rough horizontal surface. A force sensor records the applied force at five positions:

Distance (m)	0.0	0.5	1.0	1.5	2.0
Force (N)	8.0	8.1	7.9	8.0	8.0

Additional data:
Mass of block: 0.5 kg
Total distance: 2.0 m
Average applied force: 8.0 N
Change in thermal energy of block and surface: 14.0 J

Calculate the work done by the applied force over 2.0 m. [2]

The student claims all work done against friction converts entirely to thermal energy in the block and surface. Deduce whether the data support this claim. [2]

Identify and analyse one source of systematic error and one source of random error in this experiment, explaining how each affects the calculated work or measured thermal energy. [1]

Solutions

35QuestionEfficiency = Useful Output Total Input x 100Assessment Practice

6 marks~9 minCriterion D

A hospital replaces its entire lighting system with LED bulbs. Each LED bulb consumes 10 W of electrical power and delivers 8 W as useful light output.

Define energy efficiency and state its formula. Use the data above to calculate the efficiency of one LED bulb. [2]

Explain how LED technology achieves higher efficiency than incandescent bulbs, referring to the energy conversion processes involved. [2]

Evaluate the societal benefits and limitations of large-scale adoption of LED lighting in public infrastructure such as hospitals. [2]

Solutions

36QuestionUnits Joules Watts and Their ConversionsAssessment Practice

6 marks~9 minCriterion B

A wind turbine's electrical power output is monitored over four separate 10-minute intervals at different wind speeds.

Wind speed (m/s)	5	7	9	11
Power output (kW)	20.00	54.88	110.80	189.20

Assume power output remains constant during each 10-minute interval.

Show that a power output of 20.00 kW is equivalent to 20 000 W, and that 10 minutes is equivalent to 600 s. State the SI unit for each quantity. [1]

Using

E = Pt

, calculate the energy produced at each wind speed during the 10-minute interval. Express each answer in joules using scientific notation. [2]

Analyse the relationship between wind speed and power output. In your answer: describe the trend; determine whether the relationship is proportional; use quantitative evidence from the data to justify your conclusion. [3]

Solutions

37QuestionFossil Fuels and Their Environmental ImpactAssessment Practice

8 marks~12 minCriterion B

Coal is ranked by carbon content and energy density: Anthracite > Bituminous > Sub-bituminous > Lignite. Sulfur content influences SO2 emissions during combustion. The table below shows sulfur content (percentage by mass) for three coal types sampled from three mines.

Anthracite — Mine A	0.5%	Mine B: 0.6%	Mine C: 0.4%
Bituminous — Mine A	1.5%	Mine B: 1.7%	Mine C: 1.3%
Lignite — Mine A	3.0%	Mine B: 3.2%	Mine C: 2.8%

Describe the trend in sulfur content across the three coal types shown. [2]

Calculate the average sulfur content for each coal type and use these values to deduce the expected range of sulfur content for sub-bituminous coal. [3]

A power station manager claims that switching from bituminous to sub-bituminous coal will have a negligible impact on SO2 emissions. Evaluate this claim using your results from (b) and your understanding of coal combustion. [3]

Solutions

38QuestionTypes of Renewable Energy SourcesAssessment Practice

10 marks~15 minCriterion D

Three wind turbine blade designs — A, B, and C — are tested in a wind tunnel. Power output (W) is measured at wind speeds from 0 to 25 m/s. The graph shows the results.

Curve A (solid): rises steeply, plateauing at approximately 500 W beyond 15 m/s.
Curve B (dashed): rises steadily, reaching approximately 550 W at 25 m/s with no plateau.
Curve C (dotted): rises gradually, reaching approximately 400 W at 25 m/s with no plateau.

Describe the relationship between wind speed and power output shown in the graph for all three blade designs. [2]

Justify which blade design will generate the greatest power output at a wind speed of 30 m/s. [4]

Analyse two limitations of using wind tunnel data to predict the real-world performance of these blade designs. [4]

Solutions

39QuestionFossil Fuels and Their Environmental ImpactAssessment Practice

12 marks~18 minCriterion C

Figure 1 shows the infrared absorption spectra of CO2 and H2O across wavelengths 1–25 μm. Figure 2 shows a simplified energy-balance model: the atmosphere is transparent to incoming solar radiation but absorbs a fraction of outgoing infrared radiation, trapping heat near Earth's surface. Atmospheric CO2 concentration has risen from approximately 280 ppm (pre-industrial) to over 420 ppm today.

Identify the wavelength ranges at which CO2 and H2O each show strong infrared absorption, as read from Figure 1. [2]

Explain how the rise in CO2 concentration from 280 ppm to 420 ppm would affect the amount of outgoing infrared radiation escaping into space, referring to the absorption bands you identified in (a). [4]

Evaluate the ability of the simplified energy-balance model in Figure 2 to predict future global temperature changes accurately, discussing factors the model does not include. [6]

Solutions

40QuestionFossil Fuels and Their Environmental ImpactAssessment Practice

3 marks~5 minCriterion A

The diagram shows solar radiation entering Earth's atmosphere. Short-wave radiation from the Sun passes through the atmosphere and is absorbed by Earth's surface. The surface re-emits this energy as long-wave infrared radiation. Certain gases in the atmosphere absorb this outgoing infrared radiation and re-emit it in all directions, warming the lower atmosphere.

Identify one greenhouse gas responsible for absorbing outgoing infrared radiation. [1]

Explain why nitrogen (

\text{N}_2

) and oxygen (

\text{O}_2

), which make up most of the atmosphere, do not contribute to the greenhouse effect. [1]

Analyse how increasing atmospheric concentrations of greenhouse gases affect the energy balance of Earth's surface. [1]

Solutions

41QuestionFossil Fuels and Their Environmental ImpactAssessment Practice

3 marks~5 minCriterion C

The graph below shows atmospheric

\text{CO}_2

concentration (ppm) and global average temperature (°C) from 1900 to 2020. Both quantities rise over this period.

Describe the relationship between

\text{CO}_2

concentration and global average temperature shown in the graph. [1]

Explain how

\text{CO}_2

molecules in the atmosphere interact differently with incoming solar radiation and outgoing radiation from Earth's surface. [1]

Explain how increasing

\text{CO}_2

concentration causes the temperature trend shown in the graph. [1]

Solutions

42QuestionGlobal Energy Use and SustainabilityAssessment Practice

12 marks~18 minCriterion D

A small coastal community installs a wave energy converter (WEC) to power their local hospital. A floating buoy, connected via a hydraulic piston to a seabed anchor, drives a turbine and generator. The diagram shows the buoy rising and falling with waves, with arrows indicating energy flow: wave motion → hydraulic system → turbine → generator.

Explain how the WEC transforms the kinetic energy of ocean waves into electrical energy. [2]

Discuss two environmental benefits of using the WEC instead of a diesel generator to power the hospital. [4]

The hospital requires a continuous, reliable power supply. Evaluate whether wave energy alone is sufficient to meet this requirement, considering intermittency, environmental impact, and maintenance. [6]

Solutions

43QuestionPressure in Liquids / GasesAssessment Practice

12 marks~18 minCriterion B

A group of students investigates how pressure changes with water depth using a pressure sensor fixed at the bottom of a tall transparent cylinder. They add water in measured increments and record the following data:

Depth (cm)	0	10	20	30	40	50
Pressure (Pa)	101 325	102 300	103 275	104 250	105 225	106 200

Construct a procedure for this investigation. Include the equipment needed, how variables are controlled, and how reliable data will be collected. [4]

Analyse the data to describe the relationship between water depth and pressure. Support your answer with calculations. [4]

The students claim their data can be used to determine the density of water without any additional equipment. Evaluate this claim, showing your reasoning and any calculations. [4]

Solutions

44QuestionHydraulic SystemsAssessment Practice

12 marks~18 minCriterion A

A hydraulic jack lifts a car using an output piston of area

A_{output} = 0.20 \text{ m}^2

. A student records output force and input force for three different input piston areas, producing three straight lines (A, B, C) through the origin on the graph provided. The input piston area for line A is

0.010 \text{ m}^2

Deduce the pressure of the hydraulic fluid from line A. Show all working. [3]

Calculate the input piston areas for lines B and C, using their slopes from the graph. Show all working. [4]

Analyse how all three lines on the graph would change if the output piston area were doubled to

0.40 \text{ m}^2

, while all input piston areas remain unchanged. [5]

Solutions

45QuestionHydraulic SystemsAssessment Practice

4 marks~6 minCriterion C

A student builds a model hydraulic system using two syringes of different cross-sectional areas, connected by a tube filled with water. The input syringe has a cross-sectional area of 2 cm² and the output syringe has a cross-sectional area of 6 cm². A force of 10 N is applied to the input piston.

State the property of liquids that makes them suitable as the working fluid in a hydraulic system. [1]

The student replaces the water with air. Explain how this change affects pressure transmission in the system, with reference to compressibility. [2]

Evaluate the consequences of using a compressible fluid in a real hydraulic braking system. [1]

Solutions

46QuestionHydraulic SystemsAssessment Practice

6 marks~9 minCriterion D

Hydraulic fracturing, commonly known as fracking, is a technique used to extract natural gas from shale rock formations. This process involves injecting a high-pressure fluid, primarily water, sand, and chemicals, into the wellbore to create fractures in the rock, allowing natural gas to flow to the surface. Hydraulic systems are essential for generating and controlling the high pressures required for this process.

Evaluate the ethical and environmental implications of using hydraulic systems in fracking, considering the following aspects:

Describe two potential environmental risks associated with fracking, explaining how hydraulic systems contribute to these risks. [4 marks]

Discuss the potential economic benefits and gains in energy independence that fracking can provide. [4 marks]

Considering your answers to (a) and (b), evaluate whether the potential benefits of fracking outweigh the environmental and ethical concerns. Justify your reasoning. [4 marks]

Solutions

47QuestionHydraulic SystemsAssessment Practice

10 marks~15 minCriterion D

A hydraulic car lift in a repair shop has an input piston of radius

r_1 = 5\ \text{cm}

and an output piston of radius

r_2 = 20\ \text{cm}

. The pistons are connected by hydraulic fluid. A technician applies a force to the input piston to raise a car.

A force of 150 N is applied to the input piston. Calculate the pressure transmitted to the hydraulic fluid. [2]

Deduce the pressure acting on the output piston, and calculate the force the output piston exerts. [4]

The car weighs 14 400 N. Evaluate whether a single technician, who can exert a maximum force of 900 N, is able to lift the car using this hydraulic system. Justify your answer with calculations. [4]

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Solutions

48QuestionHydraulic SystemsAssessment Practice

3 marks~5 minCriterion A

A hydraulic excavator uses a hydraulic arm to lift heavy loads on construction sites. The operator pushes a control lever, causing a pump to pressurize hydraulic fluid inside a sealed cylinder.

Identify the physical principle that allows pressure applied at the pump to move the excavator arm at a distant cylinder. [1]

Explain how pressure is transmitted through the hydraulic fluid to produce a larger force at the excavator arm's cylinder than the pump applies. [1]

Discuss one societal benefit and one societal drawback of using hydraulic excavators in large-scale construction. [1]

Solutions