AQA GCSE Physics Physics Paper 2 (Higher), June 2023: Question 1

✅ Correct Answer

perpendicular

💡 Key Knowledge

In a transverse wave, oscillations (vibrations) are at right angles (perpendicular) to the direction in which energy is transferred. Examples include all electromagnetic waves, such as infrared radiation.

🧠 Exam Technique (Level of Response)

To hit Level 3 (5–6 marks), your method must be logical, repeatable, and explicitly detail control variables and measurements over time.

• Heat water using a kettle.
• Add equal volumes of hot water into both the silver-coloured flask and the black-coloured flask.
• Insert a thermometer into each flask or place an infrared detector at a fixed, equal distance from each flask.
• Record initial temperatures (or initial detector readings).
• Use a stop clock to time 10 minutes, then record the final temperatures (or final readings).
• Calculate the temperature decrease (or change in IR reading) and compare them to test the hypothesis.

❌ Common Errors

Students often lose marks by forgetting to specify that starting temperatures and volumes of water must be identical. Vague descriptions like "measure the heat" instead of measuring temperature with a thermometer will not gain credit.

✅ Correct Answer

Tick: During the 1st minute [1 mark]

Reason: There is the greatest temperature difference between the hot water and the surroundings [1 mark]

💡 Key Knowledge

The rate of infrared emission depends heavily on the temperature difference between an object and its surroundings. A higher temperature gradient causes a faster transfer of thermal energy via infrared radiation.

✅ Correct Answer

the temperature increase (or temperature change after 10 minutes) [1 mark]

❌ Common Errors

Do not write "temperature decrease" since these cubes were absorbing radiation and getting warmer, not cooling down.

✅ Correct Answers (Any two)

• Black surfaces absorb more infrared than white surfaces.
• Matt surfaces absorb more infrared than shiny surfaces of the same colour.
• Matt black is the best absorber and shiny white is the worst absorber.

🧠 Exam Technique

Make direct comparisons using data from the table. Refer explicitly to surface colour (black vs white) and texture (matt vs shiny) to secure both available marks.

✅ Correct Answer

Tick: pressure = force / area [1 mark]

💡 Key Knowledge

Recall standard physics formulas from the equations sheet. Pressure ( Pa ) equals force ( N ) divided by area ( m² ).

📐 Step-by-Step Calculation

1. Calculate the base area:
   Area = 0.12 m × 0.12 m = 0.0144 m²
2. State the rearranged equation:
   Force = Pressure × Area
3. Substitute values:
   Force = 1500 × 0.0144
4. Calculate final answer:
   Force = 21.6 N (Accept 22 N)

❌ Common Calculation Traps

• Unit mismatch: Failing to use metres correctly, or forgetting that area requires squared units ( m² ).
• Process error: Dividing pressure by area instead of multiplying when rearranging for force. Always write out your working step-by-step to pick up error-carried-forward (ecf) marks.