Chapter 3: Electricity – Circuits and Their Components

Introduction

Electricity powers our homes, schools, and industries. Understanding circuits, components, and how current flows is essential for safe and efficient use.

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1. Electric Current

• Current is the flow of electric charge through a conductor.
• Measured in amperes (A).
• Requires a closed path for flow, called an electric circuit.

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2. Electric Circuit

• A circuit is a complete path for current to flow.
• Components of a circuit:
  1. Battery/Cell – Provides energy
  2. Conducting wires – Connect components
  3. Switch – Opens or closes the circuit
  4. Load (e.g., bulb, motor) – Device that consumes energy

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3. Types of Circuits

1. Series Circuit – Components connected one after another
   • Current is the same in all components
   • If one component fails, the whole circuit stops
2. Parallel Circuit – Components connected in separate branches
   • Current divides among branches
   • If one component fails, others continue working

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4. Safety Precautions

• Avoid touching live wires
• Switch off appliances before repair
• Do not overload circuits
• Use insulated wires

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5. Key Points to Remember

• Current flows only in a closed circuit.
• Series circuits: same current, total voltage divides
• Parallel circuits: voltage same across branches, current divides
• Switch controls the flow of current
• Batteries provide energy for current

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Questions – Electricity: Circuits and Their Components

1. Very Short Answer (1 mark)

1. What is electric current?
2. Name two components of a simple circuit.
3. What does a switch do?
4. Give one example of a load in a circuit.
5. What is measured in amperes?
6. Name one source of electrical energy.
7. What is a closed circuit?
8. Give one example of a series circuit.
9. Give one example of a parallel circuit.
10. Why is insulation important for wires?

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2. Multiple Choice Questions (MCQ)

1. Current is measured in:
   a) Volts
   b) Amperes
   c) Ohms
   d) Watts
2. In which circuit does one failure stop the whole circuit?
   a) Series
   b) Parallel
   c) Both
   d) None
3. The purpose of a switch is to:
   a) Provide energy
   b) Measure current
   c) Open or close the circuit
   d) Increase voltage
4. Which of the following is a source of electrical energy?
   a) Battery
   b) Bulb
   c) Wire
   d) Switch
5. A bulb in parallel circuit continues to glow even if another bulb:
   a) Burns out
   b) Shines brighter
   c) Is replaced
   d) Is connected in series

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3. Fill in the Blanks

1. Electric current is the flow of __________.
2. A __________ provides energy for the circuit.
3. A __________ controls the flow of current.
4. Components connected in one path form a __________ circuit.
5. In a parallel circuit, the current __________ among branches.

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4. True/False Type

1. Current can flow in an open circuit. (True/False)
2. A series circuit has the same current in all components. (True/False)
3. A parallel circuit has multiple paths for current. (True/False)
4. A battery stores energy. (True/False)
5. Overloading a circuit is safe if the wires are thick. (True/False)

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5. Short Answer Questions (2–3 marks)

1. Define electric circuit.
2. Name and describe two types of circuits.
3. What is the function of a load in a circuit?
4. Give two safety precautions while handling electricity.
5. Why is a closed path necessary for current flow?

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6. Long Answer Questions (4–5 marks)

1. Explain the components of a simple electric circuit with a diagram.
2. Describe the difference between series and parallel circuits.
3. Explain how a switch works in a circuit.
4. Describe safety measures to prevent accidents while using electricity.
5. Explain how batteries provide energy for electric circuits.

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7. Higher-Order Thinking (HOT) & Application

1. If one bulb goes out in a series circuit, what happens to the others? Explain why.
2. How would you design a circuit to ensure multiple bulbs glow independently?
3. Explain why using insulated wires is important in household wiring.

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8. Passage-Based Questions

Read the passage and answer:
Electric current is the flow of charge through a conductor. A simple circuit consists of a battery, wires, switch, and load. Series circuits have a single path; parallel circuits have multiple paths. Safety measures like insulation and switches prevent accidents.

1. Name two components of a simple circuit.
2. What happens in a series circuit if one component fails?
3. Give one advantage of a parallel circuit.
4. Why are safety measures necessary when handling electricity?

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Answer Key – Electricity: Circuits and Their Components

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1. Very Short Answer

1. Flow of electric charge
2. Battery, wire, switch, bulb
3. Opens or closes the circuit
4. Bulb, motor, fan
5. Current
6. Battery, cell, generator
7. Circuit where current can flow continuously
8. Bulbs connected in series in a torch
9. House wiring (parallel)
10. Prevents electric shock and accidents

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2. MCQ Answers

1. b) Amperes
2. a) Series
3. c) Open or close the circuit
4. a) Battery
5. a) Burns out

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3. Fill in the Blanks

1. electric charge
2. battery/cell
3. switch
4. series
5. divides

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4. True/False

1. False
2. True
3. True
4. True
5. False

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5. Short Answer

1. An electric circuit is a complete path for current to flow.
2. Series – single path, same current; Parallel – multiple paths, current divides
3. Load consumes energy (e.g., bulb glows, motor runs)
4. Switch off before repair, avoid touching live wires, do not overload circuit
5. Current needs a closed path to flow

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6. Long Answer

1. Components: Battery – provides energy; Wires – connect circuit; Switch – control; Load – uses energy (diagram optional)
2. Series – single path, same current, failure stops all; Parallel – multiple paths, failure of one does not affect others
3. Switch – opens (breaks) or closes (completes) circuit
4. Safety: Insulated wires, switches, circuit breakers, proper load management
5. Battery converts chemical energy to electrical energy, driving current through the circuit

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7. HOT & Application

1. All bulbs stop glowing in series – because current cannot flow
2. Use parallel branches for each bulb – ensures independent operation
3. Insulated wires prevent electric shocks and short circuits

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8. Passage-Based

1. Battery, switch, wires, load
2. All components stop working
3. Multiple bulbs can work independently
4. To prevent shocks, accidents, and fire hazards