AQA GCSE Combined Science: Trilogy Physics Paper 2 (Higher), 2023: Question 4

💡 Big ideas

• An object staying still links to inertia .
• A current-carrying wire in a magnetic field experiences a force .
• Bigger current or a stronger magnetic field gives a bigger force.
• Repulsion is the key evidence for a permanent magnet.
• A compass aligns with the Earth’s magnetic field .

🧠 How marks are won

• Use the exact physics word when a 1-mark definition is asked.
• For explain questions, give both the change and the effect.
• For magnet tests, do not just say “see if it attracts” — attraction alone is not enough.
• For the compass question, include both what the compass does and what that means.

✅ Correct answer

inertia

💡 Key knowledge

Inertia is the tendency of an object to resist changes in its motion. That means an object at rest tends to stay at rest, and an object moving tends to keep moving at the same speed in the same direction.

❌ Common errors

• Writing momentum — not correct here.
• Writing force or friction .
• Describing the idea without using the required keyword.

🧠 Exam technique

On one-word completion questions, the examiner is looking for the exact scientific term. No extra explanation is needed.

✅ Correct answer

The copper rod accelerates to the right →

💡 Key knowledge

• This is the motor effect.
• When current flows through a conductor in a magnetic field, the conductor experiences a force.
• The direction depends on the current and the magnetic field direction.

🧠 Exam technique

In multiple-choice or tick-box direction questions, check the current direction and magnetic field direction carefully. If you know Fleming’s left-hand rule, use it. Here, the mark scheme confirms the correct direction is right.

❌ Common errors

• Choosing up or down because of the rod’s sloping position in the diagram.
• Mixing up the direction of current with the direction of force.
• Guessing from the picture instead of applying motor effect knowledge.

✅ Correct answers

One acceptable answer:

• Increase the current
• so that the (resultant) force increases.

Also allowed: use a stronger magnet, so the force on the rod increases.

💡 Key knowledge

• Acceleration increases when the resultant force increases.
• In the motor effect, a bigger current gives a bigger force.
• A stronger magnetic field also gives a bigger force.

🧠 Exam technique

A full-mark structure:

1. State one change: increase the current or use a stronger magnet .
2. Link it to force: this increases the force on the rod .
3. If you want, extend to acceleration: so the rod accelerates more .

Top answers clearly linked the practical change to the physics reason.

❌ Common errors

• Saying only increase the current and not explaining why.
• Saying increase the voltage without linking to increased current/force.
• Talking about speed instead of acceleration and never mentioning force.

Examiner insight: many students gained 1 mark for the method but lost the second mark because they did not explain that the force increases.

📐 Physics link

You are not calculating here, but the idea is: bigger resultant force → bigger acceleration.

✅ Correct answer

• Bring the same end of the iron bar close to each pole (end) of the permanent magnet.
• If there is repulsion, the iron bar is a permanent magnet.

Alternative valid idea: if one end of the iron bar is attracted to both poles, it is not a permanent magnet.

💡 Key knowledge

• A permanent magnet has its own poles.
• Like poles repel; unlike poles attract.
• An unmagnetised iron bar is attracted by either pole because it becomes magnetised by induction.
• So repulsion is the sure sign that both objects are magnets.

🧠 Exam technique

This is a classic magnetism question. The best answers mention repulsion, not just attraction. Attraction does not prove the bar is a permanent magnet.

❌ Common errors

• Saying if it attracts, it is a magnet — this is not enough.
• Not saying to test the same end of the iron bar against both poles.
• Forgetting to state what the observation means.

Examiner insight: students often lost marks by describing only attraction. The stronger answers explained that repulsion is the evidence for a permanent magnet.

✅ Correct answer

A compass needle always points in the same direction (or points north)

because it aligns itself with the Earth’s magnetic field.

💡 Key knowledge

• A compass needle is a small magnet.
• Magnets align with magnetic fields.
• If the compass consistently points in one direction, there must be a magnetic field affecting it.
• That field is the Earth’s magnetic field.

🧠 Exam technique

Good 2-mark answer pattern:

1. State the observation: the needle points in the same direction / north.
2. Explain the reason: it aligns with the Earth’s magnetic field.

Keep it simple and direct. This is an evidence question, not a long description of navigation.

❌ Common errors

• Saying only it points north with no explanation.
• Saying Earth is a magnet without mentioning the compass aligning with its magnetic field.
• Talking about gravity or the Sun instead of magnetic fields.

Examiner insight: the second mark depended on linking the compass behaviour to alignment with Earth’s magnetic field.

✅ Answers in order

• 04.1: inertia
• 04.2: right →
• 04.3: increase current so force increases
• 04.4: test one end against both poles; repulsion means it is a permanent magnet
• 04.5: compass points same direction / north because it aligns with Earth’s magnetic field

🧠 Final examiner advice

• Use exact scientific words for 1-mark recall questions.
• In 2-mark explain questions, make sure you give cause + effect.
• For magnet tests, remember: repulsion proves magnetism.
• For compass questions, say both what it does and why.