Chapter 3: Electricity: Circuits and Their Components
Introduction
Electricity is an essential part of our daily lives, powering countless devices and
systems. From our homes and schools to industries and transportation, electricity plays
a crucial role.
• Sources of Electricity: Electricity can be generated in various ways, including:
o Windmills (using wind energy)
o Solar panels (capturing the Sun's energy)
o Falling water (hydroelectric power)
o Natural gas or coal (thermal power plants)
• Electricity Supply: The electricity generated from these sources reaches our
homes and factories through wires. We plug in various devices to electrical
sockets in the wall.
• Portable Sources: For learning about electricity, we will focus on portable
sources like batteries or cells, commonly found in devices such as torchlights,
wall clocks, radios, and remotes.
3.1 A Torchlight
A torchlight, also known as a torch or flashlight, is a common device that uses
electricity to produce light.
Activity 3.1: Let us explore
Aim: To observe the components and working of a torchlight.
Materials: A torchlight.
Procedure:
1. Take a torchlight.
2. Observe it carefully. Look for a lamp (bulb) and a switch.
3. Slide the switch to one position and observe if the torch lamp glows.
4. Slide the switch back to its original position and observe the torch lamp again.
5. Open the torchlight and see what is inside.
Observations:
• You will notice a lamp and a switch.
, • In one position of the switch, the torch lamp glows.
• In the other position, the lamp does not glow.
• Inside the torchlight, you will find two or more electric cells.
Conclusion: The switch controls the flow of electricity to the lamp, making it glow or
not glow. Electric cells are the source of electricity in a torchlight.
3.2 A Simple Electrical Circuit
To understand how a torch works, we need to know about its components.
3.2.1 Electric Cell
An electric cell is a portable source of electrical energy.
Activity 3.2: Let us observe
Aim: To identify the terminals of an electric cell.
Materials: An electric cell.
Procedure:
1. Take an electric cell.
2. Turn it around and look at it carefully.
3. Look for a positive (+) sign and a negative (-) sign marked on the cell.
, 4. Notice if it has a small protruding metal cap on one side and a flat metal disc on
the other side.
Observations:
• All electric cells have two terminals: one is called positive (+ve) and the other is
negative (-ve).
• The small protruding metal cap is the positive terminal.
• The flat metal disc is the negative terminal.
Conclusion: An electric cell has two distinct terminals, positive and negative, which are
crucial for its function as a power source.
3.2.2 Battery
A battery is a combination of two or more electric cells connected together.
Activity 3.3: Let us experiment
Aim: To understand how cells are arranged in a torch to form a battery.
Materials: A torchlight that uses two cells.
Procedure:
1. Open the cell compartment of the torch and take out the cells.
Introduction
Electricity is an essential part of our daily lives, powering countless devices and
systems. From our homes and schools to industries and transportation, electricity plays
a crucial role.
• Sources of Electricity: Electricity can be generated in various ways, including:
o Windmills (using wind energy)
o Solar panels (capturing the Sun's energy)
o Falling water (hydroelectric power)
o Natural gas or coal (thermal power plants)
• Electricity Supply: The electricity generated from these sources reaches our
homes and factories through wires. We plug in various devices to electrical
sockets in the wall.
• Portable Sources: For learning about electricity, we will focus on portable
sources like batteries or cells, commonly found in devices such as torchlights,
wall clocks, radios, and remotes.
3.1 A Torchlight
A torchlight, also known as a torch or flashlight, is a common device that uses
electricity to produce light.
Activity 3.1: Let us explore
Aim: To observe the components and working of a torchlight.
Materials: A torchlight.
Procedure:
1. Take a torchlight.
2. Observe it carefully. Look for a lamp (bulb) and a switch.
3. Slide the switch to one position and observe if the torch lamp glows.
4. Slide the switch back to its original position and observe the torch lamp again.
5. Open the torchlight and see what is inside.
Observations:
• You will notice a lamp and a switch.
, • In one position of the switch, the torch lamp glows.
• In the other position, the lamp does not glow.
• Inside the torchlight, you will find two or more electric cells.
Conclusion: The switch controls the flow of electricity to the lamp, making it glow or
not glow. Electric cells are the source of electricity in a torchlight.
3.2 A Simple Electrical Circuit
To understand how a torch works, we need to know about its components.
3.2.1 Electric Cell
An electric cell is a portable source of electrical energy.
Activity 3.2: Let us observe
Aim: To identify the terminals of an electric cell.
Materials: An electric cell.
Procedure:
1. Take an electric cell.
2. Turn it around and look at it carefully.
3. Look for a positive (+) sign and a negative (-) sign marked on the cell.
, 4. Notice if it has a small protruding metal cap on one side and a flat metal disc on
the other side.
Observations:
• All electric cells have two terminals: one is called positive (+ve) and the other is
negative (-ve).
• The small protruding metal cap is the positive terminal.
• The flat metal disc is the negative terminal.
Conclusion: An electric cell has two distinct terminals, positive and negative, which are
crucial for its function as a power source.
3.2.2 Battery
A battery is a combination of two or more electric cells connected together.
Activity 3.3: Let us experiment
Aim: To understand how cells are arranged in a torch to form a battery.
Materials: A torchlight that uses two cells.
Procedure:
1. Open the cell compartment of the torch and take out the cells.
