Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
(a) State the shape of magnetic field lines around the wire. (1 mark)
(b) If the current is doubled, how does the magnetic field at a fixed point change? (1 mark)
(c) If the distance from the wire is doubled at fixed current, how does the field change? (1 mark)
(d) For current upward, state the rule used to find the direction of the compass deflection. (2 marks)