Electricidad y electromagnetismo · GCSE Physics Topic 7 (Magnetism & Electromagnetism)
Simulador de campo magnético en solenoides
Simulador de campo magnético en solenoides y regla de la mano derecha: electroimanes
- Cálculo en cliente
- Sin registro
- Derivación en vivo
- Modo proyector
- Hoja de trabajo A4
Ventana de simulación 3D● 60 FPS
Variables de control del experimento
A
vueltas
Derivaciones y métricas en tiempo real
Campo magnético central B
--
Polo magnético izquierdo
--
Polo magnético derecho
--
Alfileres atraídos
--
Derivación de fórmulas en tiempo real
Fórmula básica:
--Sustitución de valores:
--Estado físico: --
Ejemplos clásicos y análisis de errores en exámenes
Worked Problem
Problema: In Oersted experiment, a wire above a compass deflects the needle when energized. What does this prove? What if wire is oriented east-west?
Derivación paso a paso:
- Proves electricity generates magnetism. Placed east-west (perpendicular), magnetic field lines run parallel to the needle axis and fail to deflect it.
Worked Problem
Problema: What are 3 critical factors controlling electromagnet strength?
Derivación paso a paso:
- 1) Current magnitude (higher current = stronger field); 2) coil turn count (more turns = stronger field); 3) ferromagnetic core insertion.
Hoja de indagación en clase y tareas
Q1. Variant 1: In electromagnet experiments, how is magnetic strength gauged? What experimental methodology is this?
Answer Key: Count the number of paper clips or iron pins attracted. This is the "conversion method" (measuring invisible field via visible effect).
Q2. Variant 2: Why are electromagnet cores made of soft iron rather than hard carbon steel?
Answer Key: Soft iron has low magnetic retentivity: it magnetizes fast and drops to zero magnetism when switched off. Steel becomes a permanent magnet.
Q3. Variant 3: What is the operating mechanism of an electromagnetic relay? What role does it play in automation?
Answer Key: A low-voltage control circuit energizes an electromagnet to trigger high-voltage main contacts, enabling remote and safe switching.
Preguntas frecuentes y errores conceptuales
If a bar magnet snaps in half, do isolated N and S poles exist?
No! Each broken half instantly forms both N and S poles at the break. Nature has no isolated magnetic monopoles.
Are Earth's magnetic poles aligned with geographic poles?
No! Earth's magnetic S-pole lies near geographic North. The angular discrepancy is the magnetic declination (first recorded by Shen Kuo).
Why does heating a permanent magnet over a flame destroy its magnetism?
Thermal agitation disorders aligned microscopic magnetic domains, randomizing orientations and destroying net bulk magnetization (Curie point).
How do industrial electromagnetic cranes pick up and drop 20 tons of scrap steel at will?
Powering up magnetizes the massive coil to grip scrap iron. Cutting current instantly collapses the soft iron core field, releasing the load.