Introduction:

The positive and negative terminals in a bulb play a crucial role in allowing the flow of electricity and producing light. Understanding the purpose of these terminals is fundamental to comprehend how a bulb functions.

Purpose of Positive Terminal:

The positive terminal, also known as the anode, serves multiple purposes in a bulb:

1. Power Source Connection: The positive terminal of the bulb is connected to the positive end of a power source, such as a battery or electrical circuit. This connection allows the flow of electric current to the bulb.

2. Current Flow: When the circuit is closed, the positive terminal becomes the entry point for the electric current. The current flows from the positive terminal through the bulb's filament.

3. Heating the Filament: The electric current passing through the filament of the bulb encounters resistance, resulting in the generation of heat. The positive terminal provides the necessary current to heat the filament.

4. Electron Flow: In a bulb, the flow of electrons is from the negative terminal to the positive terminal. The positive terminal attracts the negatively charged electrons, which pass through the filament, creating the necessary conditions for light production.

Purpose of Negative Terminal:

The negative terminal, also referred to as the cathode, complements the positive terminal and contributes to the proper functioning of the bulb:

1. Electron Source: The negative terminal is connected to the negative end of the power source. It serves as the source of electrons required for the flow of electric current.

2. Electron Flow: As mentioned earlier, the flow of electrons within the bulb is from the negative terminal to the positive terminal. The negative terminal provides the electrons that are pulled towards the positive terminal.

3. Electron Return Path: After passing through the filament and contributing to light production, the electrons need a path to return to the power source. The negative terminal serves as the exit point for the electrons, allowing them to complete the circuit and flow back to the power source.

Conclusion:

The positive and negative terminals in a bulb have distinct purposes. The positive terminal connects the bulb to the power source, facilitates the flow of electric current, and heats the filament. On the other hand, the negative terminal acts as the source and return path for electrons, ensuring the completion of the circuit. Understanding the roles of these terminals helps us comprehend the functioning of a bulb and how it produces light.

Connecting the torch bulb to the cell: For this, you need to attach the wires to the two ends of the cell. The positive pole of the cell should be connected to the positive terminal of the bulb. Similarly, the negative pole of the cell should be connected to the negative terminal of the bulb.