Topic 1 · pp. 127–130 · Free
Topic Notes · Easy summaries with diagrams
Chapter 17 — Chapter 17 — Electromagnetism
0 of 5 steps done ✓ (4 topics + Exercise)
Topic 1 of 4
📘Easy summary
Moving charges (current) produce a magnetic field (Oersted, 1820); no current → no field, showing electricity and magnetism are linked (electromagnetism). Straight wire: concentric circles around the wire in a plane perpendicular to it. Right-hand grip rule: grip wire with right hand, thumb along current → curled fingers give field direction. Reversing current reverses field; strength increases with current and decreases with distance. Solenoid: field like a bar magnet; grip coil with fingers along current, thumb points to N pole. Demonstration: wire through cardboard with iron filings/compasses shows circular pattern. Magnetic poles: like repel, unlike attract; isolated single pole doesn't exist. Identify poles of unmarked magnet: suspend freely — end pointing geographic north is N; or check repulsion with a known magnet's pole (repulsion is the true test).
⭐Key points
- Thumb = current, fingers = field.
🔬Diagram
🌿Real-life example
Iron filings form circles around wire.
💡Exam tip
- Repulsion confirms polarity.
✅Quick check
1. Steady current produces:
2. Current reversed → field:
Practice this chapter
Lock it in with flashcards and exam-style MCQs.