๐ Class 7 Science Curiosity – Chapter 3 Solutions
⚡ Electricity: Circuits and their Components | Amresh Academy
๐ ๐น Let Us Enhance Our Learning
1. Choose the incorrect statement.
2. Observe Fig. 3.16. With which material connected between the ends A and B, the lamp will not glow?
3. In Fig. 3.17, if the filament of one of the lamps is broken, will the other glow? Justify your answer.
4. A student forgot to remove the insulator covering from the connecting wires while making a circuit. If the lamp and the cell are working properly, will the lamp glow?
5. Draw a circuit diagram for a simple torch using symbols for electric components.
6. In Fig. 3.18:
7. Vidyut has made the circuit as shown in Fig. 3.19. Even after closing the circuit, the lamp does not glow. What can be the possible reasons? List as many possible reasons as you can for this faulty operation. What will you do to find out why the lamp did not glow?
๐ Answer:
Possible reasons:
- Fused bulb ๐ก❌
- Dead cell ๐
- Loose connection
- Broken wire
- Faulty switch
- Wrong polarity
- Insulation not removed
8. In Fig. 3.20, in which case(s) the lamp will not glow when the switch is closed?
9. Suppose the ‘+’ and ‘-‘ symbols cannot be read on a battery. Suggest a method to identify the two terminals of this battery.
10. You are given six cells marked A, B, C, D, E, and F. Some of these are working and some are not. Design an activity to identify which of them are working. (i) List the items that you require. (ii) Write the procedure that you will follow. (iii) With the items, carry out the activity to identify the cells that are working.
๐ Answer:
(i) Items → bulb ๐ก, wires ๐
(ii) Procedure:
- Make circuit
- Insert one cell
- Check glow
11. An LED requires two cells in series to glow. Tanya made the circuit as shown in Fig. 3.21. Will the lamp glow? If not, draw the wires for correct connections.
๐ Correct connection:
- Cells → + to – ๐
- LED → correct polarity
✍️ ๐น Very Short Answer Type Questions
What is the function of a switch in an electric circuit?
๐ Completes or breaks circuit ๐
What does an electric cell provide to a circuit?
๐ Electrical energy ๐
Name the two terminals of a cell.
๐ Positive (+) & Negative (–)
Why does an LED glow only in one direction?
๐ Current flows in one direction ⚡
What is a filament in an incandescent lamp?
๐ Thin glowing wire ๐ก
๐ง ๐น Short Answer Type Questions
Why is it important to connect electric cells in a particular order in a torch?
๐ Series connection ensures proper current ๐
What happens when the filament of an incandescent lamp breaks?
๐ Lamp becomes fused ❌
What do we mean by an electrical circuit?
๐ Complete path of current ๐
Why are wires covered with plastic or rubber?
๐ Safety (insulation) ๐ก️
How can you identify the terminals of a battery if the symbols are not visible?
๐ Using LED or holder ✔️
๐ ๐น Descriptive Answer Type Questions
Why do LEDs need to be connected correctly in a circuit?
๐ Work only in one direction
Explain the difference between conductors and insulators with examples.
Why is copper commonly used for making wires and not gold or silver?
๐ Cheap + good conductor
What is a circuit diagram and why is it used?
๐ Symbolic representation ๐
How does a homemade switch work in a circuit?
๐ ๐น Exploring Questions
Why is it dangerous to use damaged wires or switches?
๐ Electric shock ⚠️
How would you test whether a cell is working or not using a simple circuit?
๐ Use bulb test ๐ก
If electricity is unavailable in your home for two days, list five daily tasks that would be affected.
๐ Light, phone, fridge, TV, water pump
Why do LEDs last longer and are more efficient than incandescent lamps?
๐ Less energy, no filament ⚡
Design an activity using a conduction tester to test if a material is a conductor or insulator.
