Eletricidade e eletromagnetismo · GCSE Physics Topic 7 (Magnetism & Electromagnetism)
Simulador de campo magnético de solenoide
Simulador de campo magnético de solenoides e regra da mão direita: eletroímãs
- No navegador
- Sem cadastro
- Dedução ao vivo
- Modo projetor
- Folha de exercícios A4
Janela de simulação 3D● 60 FPS
Variáveis de controle do experimento
A
voltas
Deduções e métricas em tempo real
Campo magnético central B
--
Polo magnético esquerdo
--
Polo magnético direito
--
Alfinetes atraídos
--
Dedução de fórmulas em tempo real
Fórmula fundamental:
--Substituição de valores:
--Estado físico: --
Exemplos clássicos e armadilhas de exame
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?
Derivação passo a passo:
- 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?
Derivação passo a passo:
- 1) Current magnitude (higher current = stronger field); 2) coil turn count (more turns = stronger field); 3) ferromagnetic core insertion.
Folha de investigação em aula e exercícios
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.
Perguntas frequentes e erros comuns
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.