Electric Circuits
Aperçu
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.
Objectifs
- 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
Note de cours
Disponible sur l'application Green Bridge
Téléchargez l'application Green Bridge CBT sur votre téléphone ou votre ordinateur pour accéder aux notes de cours complètes, aux questions pratiques, et plus encore.
Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Electric Circuits. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.
Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.
- 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
Disponible sur l'application Green Bridge
Téléchargez l'application Green Bridge CBT sur votre téléphone ou votre ordinateur pour accéder aux notes de cours complètes, aux questions pratiques, et plus encore.
Disponible sur l'application Green Bridge
Téléchargez l'application Green Bridge CBT sur votre téléphone ou votre ordinateur pour accéder aux notes de cours complètes, aux questions pratiques, et plus encore.
Livres recommandés
Pratiquez des questions blanches
Vous voulez vous entraîner sur des questions blanches sur Electric Circuits ? Téléchargez lapplication Green Bridge CBT pour accéder à des questions blanches et à des évaluations complètes sur ce sujet.
Téléchargez l'application sur Google Play.
Tout ce dont vous avez besoin pour exceller au JAMB, WAEC et NECO.
