NCERT Solutions for Class 7 Science Curiosity Chapter 3 help students understand key topics like heat, temperature, and thermal expansion. These solutions follow the updated 2025–26 Class 7 Science syllabus and are aligned with the latest exam pattern. Each question is answered in a clear and simple manner to help students grasp concepts quickly.
Practicing these solutions along with previous year papers boosts confidence and exam readiness.
NCERT Class 7 Science Chapter 3 Electricity: Circuits and their Components
Electricity plays a vital role in our daily lives, powering everything from lights to appliances. In this chapter, students are introduced to the basic concepts of electricity and how electric circuits work. It explains important components such as cells, wires, switches, and bulbs, and how they are connected to form a complete path for current to flow.
The chapter also highlights the difference between open and closed circuits, and the role of conductors and insulators. Through simple experiments and observations, students begin to understand the fascinating world of electric circuits and their real-life applications.
NCERT Solutions for Class 7 Science Curiosity Chapter 3 Question Answer
Below are the NCERT solutions for Class 7 Science Curiosity Chapter 3 – Electricity: Circuits and their Components. These Class 7 Science Chapter 3 Question Answer will help students understand key concepts such as electric circuits, conductors, insulators, and components like bulbs, switches, and cells. They are prepared as per the latest NCERT guidelines to assist in better exam preparation and conceptual clarity.
Activity Responses
Activity: Can you help Nihal by adding some more uses to his lists? Also, suggest some other ways of grouping the uses of electricity.
Additional Uses:
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Entertainment: Video games, smart TVs
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Communication: Landline telephone, intercom systems
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Others: Washing machine, refrigerator
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Lighting: Stadium lights, emergency lights
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Cooking: Induction stove, electric rice cooker
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Transportation: Electric rickshaws, metro trains
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Heating and Cooling: Water cooler, hair dryer
Other ways of grouping:
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Based on location: Home, school, hospital, industry
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Based on function: Domestic, industrial, medical
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Based on energy consumption: Low-power vs high-power devices
Activity 3.1: Let us explore
Why does the torch lamp glow in one position of its switch?
The torch lamp glows when the switch completes the electrical circuit, allowing current to pass through the filament or LED, thereby producing light. In the other position, the circuit is open, and the lamp does not glow.
Activity 3.2: Let us observe
What do you observe on an electric cell?
It has a positive terminal (metal cap) and a negative terminal (flat disc). These are marked with ‘+’ and ‘–’ signs.
Activity 3.3: Let us experiment
Observation:
The torch lamp glows only when the cells are placed in a series—positive terminal of one touching the negative of the next. This arrangement is called a battery.
Activity 3.4: Let us observe
Which part of the incandescent lamp glows?
The thin wire inside the glass bulb, called the filament, glows when current passes through it. The filament is supported by two thick wires that serve as terminals.
Activity 3.5: Let us observe
Does an LED have a filament?
No. An LED does not have a filament. It has two terminals—longer wire is positive, and shorter is negative.
Activity 3.6: Let us construct
Prediction and Observation Table (Table 3.1)
Only the circuits that form a closed path with proper connections will allow the lamp to glow.
Activity 3.7: Let us experiment
Observation:
The LED glows when its positive terminal (long wire) is connected to the positive terminal of the battery and vice versa.
It does not glow when the connections are reversed.
Activity 3.8 & 3.9: Let us construct and test
How does a switch turn on or off the torchlight?
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In OFF position: The safety pin does not touch both drawing pins; the circuit is open; lamp does not glow.
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In ON position: The pin touches both drawing pins, completing the circuit and allowing current to flow; lamp glows.
Activity 3.10: Let us draw
Circuit Diagrams for:
Activity 3.11: Let us identify
Table 3.3: Identifying Conductors and Insulators
| S.No. |
Object |
Material |
Lamp Glows |
Conclusion |
| 1 |
Stick |
Wood |
No |
Insulator |
| 2 |
Scale |
Plastic |
No |
Insulator |
| 3 |
Key |
Metal |
Yes |
Conductor |
| 4 |
Bangle |
Glass |
No |
Insulator |
| 5 |
Eraser |
Rubber |
No |
Insulator |
| 6 |
Paper Strip |
Paper |
No |
Insulator |
| 7 |
Candle |
Wax |
No |
Insulator |
| 8 |
Coin |
Metal |
Yes |
Conductor |
| 9 |
Pencil Lead |
Graphite (Carbon) |
Yes |
Conductor |
Let Us Enhance Our Learning – Questions & Answers
1. Choose the incorrect statement.
(i) A switch is the source of electric current in a circuit. (Incorrect)
2. Observe Fig. 3.16. With which material connected between A and B, the lamp will not glow?
Any insulating material (e.g., rubber, plastic, wood) will prevent the lamp from glowing.
3. In Fig. 3.17, if the filament of one lamp is broken, will the other glow? Justify.
No, both lamps are in series, and if the filament of one is broken, the circuit is incomplete and current won’t flow.
4. A student forgot to remove the insulation from the wires. Will the lamp glow?
No, because insulation prevents contact between wires and terminals; circuit remains incomplete.
5. Draw a circuit diagram for a simple torch using symbols.
Use symbols for:
6. In Fig. 3.18:
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(i) S2 ON, S1 OFF → L2 will glow
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(ii) S2 OFF, S1 ON → L1 will glow
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(iii) Both ON → Both L1 and L2 glow
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(iv) Both OFF → None will glow
7. Vidyut’s lamp doesn’t glow. Possible reasons:
Steps to find the problem:
8. In Fig. 3.20, in which case(s) the lamp will not glow when switch is closed?
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(a) Lamp terminals not connected correctly
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(b) Same polarity on both ends
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(c) Open circuit
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(d) Reversed LED terminals
⟶ (a), (b), and (d): Lamp will not glow
9. If battery markings are erased, how to identify terminals?
10. Identify working cells (A–F):
(i) Items Required:
Electric lamp, holder, wires, tape, and cells A to F
(ii) Procedure:
(iii) Activity:
11. Will the LED in Fig. 3.21 glow? If not, draw correct circuit.
No, because cells are not connected in series (same polarity).
Correction: Connect positive of one cell to negative of the next, and then attach to LED terminals accordingly.
Exploratory Projects
1. If power goes out for two days, what will be affected?
2. Use a solar panel to power a toy fan.
Use connecting wires from solar panel to fan terminals ensuring correct polarity.
3. Visit to electric shop – report idea:
Observe types like:
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AA/AAA cells for remotes, clocks
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Button cells for watches
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Lithium-ion for phones
Note prices, shapes, and applications.
4. Categorize household items:
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Only insulators: Plastic containers, rubber gloves
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Only conductors: Metal keys, spoons, tongs
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Mixed: Electric iron (metal plate + plastic handle), mobile charger (metal pins + plastic casing)
NCERT Solutions for Class 7 Science Curiosity Chapter 3 Extra Question Answers
Below are the extra question-answers for Class 7 Science Curiosity Chapter 3 – Electricity: Circuits and Their Components.
These questions go beyond the textbook exercises to help students deepen their understanding of concepts such as electric cells, circuits, conductors, insulators, and more.
They are designed to enhance learning and strengthen exam preparation through additional practice.
1. What is the function of an electric cell in a circuit?
Answer: An electric cell is a portable source of electrical energy. It provides the required electric current to make devices like lamps and LEDs work.
2. What are the two terminals of a cell?
Answer: The two terminals are the positive terminal (metal cap) and the negative terminal (flat metal disc).
3. Define a battery.
Answer: A battery is a combination of two or more electric cells connected in a particular order to provide more energy.
4. What is a filament in an incandescent lamp?
Answer: The filament is a thin wire inside the glass bulb of an incandescent lamp that glows when electric current passes through it.
5. What is an LED?
Answer: LED stands for Light Emitting Diode. It is a lamp that glows when current passes through it in one direction only.
6. Why does an LED glow only in one direction?
Answer: An LED allows current to pass through it in only one direction—from its positive terminal (longer wire) to its negative terminal (shorter wire).
7. What is the role of a switch in a circuit?
Answer: A switch is a device that completes or breaks a circuit. It allows us to turn electric devices on or off.
8. What is a circuit diagram?
Answer: A circuit diagram is a simplified drawing of an electrical circuit using symbols for each component.
9. What materials are generally used to make connecting wires in a circuit? Why?
Answer: Metals like copper or aluminum are used because they are good conductors of electricity.
10. Why are electrical wires covered with plastic or rubber?
Answer: Plastic or rubber is an insulator and prevents electric shock by covering the conductive metal wire.
11. What is the difference between conductors and insulators?
Answer: Conductors allow electric current to pass through them (e.g., copper), whereas insulators do not (e.g., rubber).
12. What happens if a filament in a lamp is broken?
Answer: The lamp is said to be fused and it will not glow because the current cannot pass through the broken filament.
13. Can a switch be placed anywhere in a circuit?
Answer: Yes, a switch can be placed anywhere in a circuit to control the flow of electricity.
14. Why should we never touch electrical appliances with wet hands?
Answer: Our body is a conductor of electricity, and touching appliances with wet hands can cause an electric shock.
15. Why is copper used more commonly in electrical wires than silver or gold?
Answer: Though silver and gold are better conductors, copper is used more due to its low cost and abundant availability.
NCERT Solutions for Class 7 Science Curiosity Chapter 3 PDF Download
Below, we have provided the NCERT Solutions for Class 7 Science Curiosity Chapter 3 – Electricity: Circuits and Their Components in PDF format for your convenience.
This downloadable PDF contains detailed explanations of all exercise questions, including additional questions and answers, clear diagrams of circuits, definitions of conductors and insulators, and helpful tips to reinforce understanding.
It’s formatted for easy printing and offline use, ensuring that students can review and practice even without internet access. Simply click to download and enhance your exam preparation!
