Electric Circuits
Visão Geral
Flip one switch and a whole room of lights comes on, yet unplug one fairy light and the rest stay glowing. The difference is whether the components are wired in series, one after another, or in parallel, side by side. How you connect components decides the current through each, the voltage across each, and the total resistance of the circuit.
In this lesson you will read and draw circuit diagrams, use the rule that current is the same everywhere in a series circuit, add e.m.f.s and resistances in series, use the junction rule for currents in parallel, find the combined resistance of resistors in parallel, and explain why lights at home are wired in parallel. Every calculation shows the equation, the substitution and the answer with units.
Objetivos
- Draw and interpret circuit diagrams containing cells, batteries, power supplies, generators, potential dividers, switches, resistors (fixed and variable), heaters, thermistors (NTC only), light- dependent resistors (LDRs), lamps, motors, bells, ammeters, voltmeters, magnetising coils, transformers, fuses and relays and know how these components behave in the circuit
- Know that the current at every point in a series circuit is the same
- Know how to construct and use series and parallel circuits
- Calculate the combined e.m.f. of several sources in series
- Calculate the combined resistance of two or more resistors in series
- State that, for a parallel circuit, the current from the source is larger than the current in each branch
- State that the combined resistance of two resistors in parallel is less than that of either resistor by itself
- State the advantages of connecting lamps in parallel in a lighting circuit
- [Supplement] Draw and interpret circuit diagrams containing diodes and light-emitting diodes (LEDs) and know how these components behave in the circuit
- [Supplement] Recall and use in calculations, the fact that: (a) t he sum of the currents entering a junction in a parallel circuit is equal to the sum of the currents that leave the junction (b) t he total p.d. across the components in a series circuit is equal to the sum of the individual p.d.s across each component (c) t he p.d. across an arrangement of parallel resistances is the same as the p.d. across one branch in the arrangement of the parallel resistances
- [Supplement] Explain that the sum of the currents into a junction is the same as the sum of the currents out of the junction
- [Supplement] Calculate the combined resistance of two resistors in parallel
Nota de Aula
Disponível na aplicação Green Bridge
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Avaliação da Lição
Parabéns por concluir a lição em Electric Circuits. Agora que você explorou o conceitos e ideias-chave, é hora de colocar seu conhecimento à prova. Esta seção oferece uma variedade de práticas perguntas destinadas a reforçar sua compreensão e ajudá-lo a avaliar sua compreensão do material.
Irá encontrar uma mistura de tipos de perguntas, incluindo perguntas de escolha múltipla, perguntas de resposta curta e perguntas de redação. Cada pergunta é cuidadosamente elaborada para avaliar diferentes aspetos do seu conhecimento e competências de pensamento crítico.
Use esta secção de avaliação como uma oportunidade para reforçar a tua compreensão do tema e identificar quaisquer áreas onde possas precisar de estudo adicional. Não te deixes desencorajar pelos desafios que encontrares; em vez disso, vê-os como oportunidades de crescimento e melhoria.
- In a series circuit, the current is A. largest near the battery B. the same at every point C. used up by each component D. different in each component Answer: B
- Two 1.5 V cells are connected in series the same way round. The combined e.m.f. is A. 0.75 V B. 1.5 V C. 3.0 V D. 4.5 V Answer: C
- Resistors of 3 ohm and 6 ohm in series have a combined resistance of A. 2 ohm B. 4.5 ohm C. 9 ohm D. 18 ohm Answer: C
- Resistors of 4 ohm and 12 ohm in parallel have a combined resistance of A. 3 ohm B. 8 ohm C. 16 ohm D. 48 ohm Answer: A
- Lamps in a house are wired in parallel mainly so that A. they share the current B. each can be switched independently and shines at full brightness C. they use less energy D. one failing switches them all off Answer: B
Disponível na aplicação Green Bridge
Transfira a aplicação Green Bridge CBT para o seu telemóvel ou computador para aceder a notas de aula completas, questões de prática e muito mais.
Disponível na aplicação Green Bridge
Transfira a aplicação Green Bridge CBT para o seu telemóvel ou computador para aceder a notas de aula completas, questões de prática e muito mais.
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