AQA GCSE Combined Science: Trilogy Physics Paper 1 (Higher), 2022: Question 2

15 marks · Standard Demand difficulty · Short Answer

A set of physics questions on determining specific heat capacity, using energy and power equations, interpreting thermistor graphs, and identifying a reversible physical change in water.

Practise this question

Question

The question page shows Question 2 with seven parts about heating vegetable oil. Figure 2 is a labelled equipment diagram showing a joulemeter connected to an electric heater, plus a beaker, a top pan balance, and a thermometer; students are asked to describe a method to determine the specific heat capacity of vegetable oil and then state one risk when using the apparatus. Later parts ask for the equation linking energy transferred, power and time, a calculation of time for a 50 W heater to transfer 4750 J, identification of the temperature-monitoring component in a deep fryer, and use of two graphs: Figure 3 plots resistance in ohms against temperature in degrees Celsius with a decreasing curve from about 1000 ohms at 0 degrees Celsius to under 100 ohms near 250 degrees Celsius, and Figure 4 plots temperature against time with oil warming to about 160 degrees Celsius before leveling off; the final item is a multiple-choice question about why water changing to steam is a physical change.
Question text

02 A student made measurements to determine the specific heat capacity of

vegetable oil.

Figure 2 shows the equipment used.

Figure 2

02.1 Describe how the student could use the equipment shown in Figure 2 to determine

the specific heat capacity of vegetable oil.

[6 marks]

02.2 Give one risk when using the equipment in Figure 2.

[1 mark]

A different student did not have a joulemeter and calculated the energy transferred by

the electric heater.

Use the Physics Equations Sheet to answer questions 02.3 and 02.4.

02.3 Write down the equation linking energy transferred (E), power (P) and time (t).

[1 mark]

02.4 The electric heater had a power output of 50 watts.

Calculate the time taken for the electric element to transfer 4750 joules of energy to

the vegetable oil.

[3 marks]

Time taken = s

In a deep fryer, vegetable oil is heated by an electric heating element. Food is then

cooked in the hot vegetable oil.

The deep fryer contains an electrical component to monitor the temperature of the

vegetable oil.

Figure 3 shows how the resistance of this electrical component changes

with temperature.

Figure 3

02.5 What electrical component is used to monitor the temperature of the vegetable oil?

[1 mark]

02.6 The electric heating element in the deep fryer automatically switches off when the

vegetable oil reaches a certain temperature.

Figure 4 shows how the temperature of the vegetable oil changed after the deep

fryer was switched on.

Figure 4

Determine the resistance of the electrical component when the electric heating

element automatically switched off.

Use Figure 3 and Figure 4.

[2 marks]

10 Resistance = Ω

02.7 Some chips were put in the deep fryer.

In the deep fryer, water in the chips underwent a physical change and became steam.

Why is this a physical change?

[1 mark]

Tick ( ) one box.

All water can change to steam.

No chemicals are involved when water changes to steam.

The change from water to steam can be detected visually.

The water will recover its original properties if the steam is cooled

Mark scheme

Show the mark scheme The mark scheme for Question 2 gives level-based marking for 02.1, crediting a logically sequenced method including measuring the mass of oil, measuring initial and final temperatures, heating the oil, measuring energy transferred with a joulemeter, calculating temperature rise, and using E = mcΔθ to find specific heat capacity. It awards 1 mark for 02.2 for risks such as burns or scalds, 1 mark for 02.3 for power equals energy transferred divided by time, and 3 marks for 02.4 for rearranging and calculating t = 95 s from 4750 J and 50 W. It gives 1 mark for 02.5 for thermistor, 2 marks for 02.6 for a resistance of about 250 ohms from reading 160 degrees Celsius on one graph and matching it on the other, and 1 mark for 02.7 for the statement that water recovers its original properties if the steam is cooled.

Question 2

AO /

Question Answers Mark

Spec. Ref.

02.1 Level 3: The method would lead to the production of a valid 5–6 AO1

outcome. All key steps are identified and logically sequenced. 6.1.1.3

6.3.2.2

Level 2: The method would not necessarily lead to a valid 3–4 RPA14

outcome. Most steps are identified, but the plan is not fully logically

sequenced.

Level 1: The method would not lead to a valid outcome. Some 1–2

relevant steps are identified, but links are not made clear.

No relevant content 0

Indicative content

• measure mass of oil using the top pan balance

• measure start temperature of oil using the thermometer

• place beaker of oil on heater

• switch on heater to heat oil

• measure final temperature of oil using the thermometer

• measure energy transferred using joulemeter

• calculate increase in temperature (∆θ)

• use the equation E = mcΔθ to determine c

AO /

Question Answers Extra information Mark

Spec. Ref.

02.2 burns / scalds allow cuts from broken glass 1 AO1

6.1.1.3

ignore the heater / oil is hot

RPA14

AO /

Spec. Ref.

02.3 energy transferred 1 AO1

power =

time 6.1.1.4

6.2.4.2

or RPA14

E

P =

t

AO /

Spec. Ref.

02.4 4750 1 AO2

50 =

t 6.1.1.4

or 6.2.4.2

4750 = 50 × t

4750

t = 1

t = 95 (s) 1

AO /

Spec. Ref.

02.5 thermistor 1 AO1

6.2.1.4

AO /

Spec. Ref.

02.6 250 (Ω) allow an answer in the range 2 AO3

240 (Ω) to 260 (Ω) 6.2.1.4

allow 1 mark for temperature =

160 (°C)

AO /

Spec. Ref.

02.7 the water will recover its original 1 AO1

properties if the steam is cooled 6.3.1.2

Total Question 2 15

How to answer it

Specific Heat Capacity of Vegetable Oil

What this question tests

Planning an experiment, identifying a risk, using P = E/t , rearranging to find time, reading graphs, and recognising a thermistor as a temperature sensor.

It also tests whether you can link heating, temperature change, resistance, and physical changes in a clear GCSE-style answer.

Question 2.1 — Method to determine the specific heat capacity of vegetable oil [6]

Describe how the student could use the equipment shown in Figure 2.

💡 Key knowledge

  • Measure the mass of the oil using the top-pan balance.
  • Measure the starting temperature using the thermometer.
  • Heat the oil with the electric heater.
  • Measure the final temperature after heating.
  • Measure the energy transferred using the joulemeter.
  • Calculate the temperature change: Δθ = final temperature - start temperature .
  • Use E = mcΔθ to determine the specific heat capacity, c .

🧠 Exam technique

  • Get the steps in a logical order: measure mass → measure temperatures → heat → record energy.
  • Say what is measured and which piece of equipment is used.
  • For full marks, include the final calculation idea, not just the practical steps.
  • Top answers mention that the heater should be switched on for a measured period while the oil is stirred or allowed to heat evenly.

❌ Common errors

  • Writing only “heat the oil” without saying how to find c.
  • Forgetting to measure the mass of the oil.
  • Not mentioning the initial and final temperatures.
  • Mixing up E = mcΔθ with the power equation.
  • Giving an unsequenced list of ideas, which can lose marks for method clarity.

✅ Correct answer idea

Measure the mass of the vegetable oil using the top-pan balance. Measure the starting temperature of the oil with the thermometer. Place the beaker of oil on the electric heater and switch it on to heat the oil. Measure the energy transferred using the joulemeter. Measure the final temperature with the thermometer. Find the temperature change, then use E = mcΔθ to calculate the specific heat capacity.

Marking note: This is a 6-mark planning question. A clear, linked method with all key stages can reach the top level.

📐 Why this method works

Specific heat capacity is the energy needed to raise the temperature of 1 kg of a substance by 1 °C. You need: mass, energy transferred, and temperature change.

Question 2.2 — Risk when using the equipment [1]

Give one risk.

✅ Correct answer

Burns / scalds.

Also acceptable: cuts from broken glass.

❌ Common errors

  • “The heater is dangerous” is too vague.
  • “Electric shock” is not the expected risk here.
  • Remember the oil and beaker can be hot.

Question 2.3 — Equation linking energy, power and time [1]

💡 Key knowledge

The equation is:

power = energy transferred / time

or

P = E / t

🧠 Exam technique

For one mark, writing the correct equation is enough. Make sure the symbols mean the right things:

  • P = power in watts
  • E = energy transferred in joules
  • t = time in seconds

Question 2.4 — Calculate the time taken [3]

The heater had a power output of 50 W. Calculate the time for 4750 J of energy.

📐 Step-by-step calculation

  1. Use the equation: P = E / t
  2. Substitute the values: 50 = 4750 / t
  3. Rearrange: t = 4750 / 50
  4. Calculate: t = 95
  5. Give the unit: 95 s

✅ Correct answer

Time taken = 95 s

This question awards marks for using the equation, rearranging correctly, and giving the final answer with units.

❌ Common calculation traps

  • Using 50 ÷ 4750 instead of 4750 ÷ 50.
  • Forgetting to rearrange the equation.
  • Writing the answer in minutes instead of seconds.
  • Missing the unit, which can lose the final mark.

Question 2.5 — Electrical component used to monitor temperature [1]

✅ Correct answer

Thermistor

💡 Key knowledge

A thermistor changes resistance when temperature changes. It is used as a temperature sensor in control systems.

Question 2.6 — Determine the resistance when the heater switches off [2]

Use Figure 3 and Figure 4.

📐 Step-by-step approach

  1. From Figure 4, the heater switches off at about 160 °C.
  2. Find 160 °C on Figure 3.
  3. Read the resistance value from the graph.
  4. The resistance is about 250 Ω.

✅ Correct answer

Resistance = 250 Ω

Acceptable range: 240 Ω to 260 Ω.

🧠 Exam technique

  • Use both graphs together: one gives the temperature, the other gives the matching resistance.
  • Read carefully from the axes: this is a graph-reading question, not a calculation question.
  • State the unit: Ω .

❌ Common errors

  • Reading the wrong temperature from Figure 4.
  • Using the wrong point on Figure 3.
  • Forgetting that the graph shows a thermistor, so resistance changes as temperature changes.
  • Not giving the answer with a unit.

Question 2.7 — Why is this a physical change? [1]

Tick one box.

✅ Correct answer

The water will recover its original properties if the steam is cooled.

💡 Key knowledge

A physical change does not make a new substance. Water can change between liquid and gas and still remain water.

❌ Why the other options are wrong

  • “All water can change to steam” does not explain why it is physical.
  • “No chemicals are involved” is too vague and not the key reason.
  • “The change can be detected visually” is not a definition of physical change.

What the examiner was looking for

💡 Top-level method answers

  • All essential steps included.
  • Steps in a logical order.
  • Correct scientific vocabulary: mass, temperature change, joulemeter, specific heat capacity.

🧠 How to secure marks

  • Be precise with equipment names.
  • Show working for calculations.
  • Always include units.
  • For graph questions, quote values directly from the graph.

❌ Most common mark losses

  • Missing the mass measurement in Q2.1.
  • Not stating a real risk in Q2.2.
  • Using the wrong rearrangement in Q2.4.
  • Misreading the thermistor graph in Q2.6.

Topics

Physics · Required Practicals · P1: Energy · P2: Electricity · P3: Particle Model of Matter · Physics Required Practicals

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 1 (Higher), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.