Electricity: Circuits and their Components
Short Questions
1. What is an electric cell?
Answer: A portable source of electrical energy.
2.What are the two terminals of an electric cell called?
Answer: Positive (+ve) and negative (–ve).
3.What is a battery?
Answer: A combination of two or more electric cells.
4.What makes an incandescent lamp glow?
Answer: A thin wire called the filament gets hot and glows.
5.What is an LED?
Answer: A Light Emitting Diode that glows when current passes in one direction.
6.What does a switch do in a circuit?
Answer: It completes or breaks the circuit.
7.What is an electrical circuit?
Answer: A complete path for electric current to flow.
8.What are conductors?
Answer: Materials that allow electric current to flow easily.
9.What are insulators?
Answer: Materials that do not allow electric current to flow.
10. What is a circuit diagram?
Answer: A drawing of an electrical circuit using symbols.
Long Questions
1. Why does a torch lamp glow when the switch is turned on?
Answer: The switch completes the circuit, allowing current to flow through the lamp. This makes the filament or LED glow.
2.How is an LED different from an incandescent lamp?
Answer: An LED has no filament and glows only when connected correctly. An incandescent lamp has a filament that glows when heated.
3.Why are electric wires covered with plastic or rubber?
Answer: Plastic and rubber are insulators that prevent electric shocks. They stop current from leaking or touching other objects.
4.How can you test if a material is a conductor or insulator?
Answer: Connect the material in a circuit with a lamp and cell. If the lamp glows, it’s a conductor; if not, it’s an insulator.
5.What happens if the filament of an incandescent lamp is broken?\
Answer: The lamp will not glow because the broken filament stops the current. This is called a “fused” lamp.
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