Objective- This section is designed to explain how an electric bell works, using the concept of electromagnets.
Concepts to Understand-
- Electromagnet- A type of magnet where the magnetic field is produced by an electric current.
- Electric Bell Mechanism- Involves an electromagnet, a hammer, and a gong. The electromagnet, when energised, moves the hammer to hit the gong, producing sound.
Also Check – Electric Bell Working Mechanism Simplified for Students
Components of an Electric Bell-
- Electromagnet- A coil of wire wound around an iron core.
- Iron Strip- Attached to a hammer at one end.
- Contact Screw- Adjusts the flow of current.
- Gong- A metal disc that produces sound when hit.
How the Electric Bell Works-
Initial Setup-
- The circuit of the electric bell includes a power source (battery), an electromagnet, a contact screw, and an iron strip with a hammer.
Circuit Completion-
- When the bell’s switch is turned on, the current flows through the coil, turning it into an electromagnet.
Electromagnet Activation-
- The electromagnet attracts the iron strip towards it, causing the hammer at the end of the strip to move towards the gong.
Sound Production-
- As the hammer moves, it strikes the gong, producing the ringing sound of the bell.
Circuit Interruption-
- The movement of the iron strip causes it to pull away from the contact screw, interrupting the circuit. This stops the current flow, and the electromagnet loses its magnetic power.
Resetting the Bell-
- Once the electromagnet is deactivated, the iron strip, due to its own spring action, moves back to its original position, making contact with the screw again. This completes the circuit, and the process repeats.
Understanding the Concept-
- The electric bell uses the principle of electromagnetism. The making and breaking of the circuit cause the hammer to move back and forth, continuously striking the gong as long as the switch is on.
- This demonstrates how electromagnets can be used to create mechanical motion, which is a fundamental concept in many electrical devices.
Conclusion-
Through the study of an electric bell, students learn how electromagnets can be utilised to perform work, in this case, to create sound. It provides a practical example of electromagnetism in action and illustrates how electrical energy can be converted into mechanical energy. This understanding is crucial for grasping more advanced concepts in physics and electrical engineering.
Also Check – Chapter 10: A Detailed Guide to “Electric Current and its Effects” Activities for Class 7 Students
Also Check- Electromagnets- A Guide for Upper Primary Students
Also Check- Chapter 10 – Electric Current and its Effects – 5 Worksheets Solved and Unsolved
Also Check- Electric Bell Diagram for Class 7 Science
Also Check- Rapid Revision – Class 7 Science- Chapter 14 – Electric Current and Its Effects
Also Check- Chapter 14- Electric Current and Its Effects-Class 7 science- Question and Answers
Also Check- Chapter 14- Electric Current and Its Effects–Class 7 science- Question and Answer -(Solved MCQs)
Also Check- NCERT Exemplar Solutions- Class 7 Science- Chapter 14 – Electric Current and Its Effects
Also Check- NCERT Solutions for Class 7 Science Chapter 14- Electric Current and its Effects
Also Check- Class 7 science -Chapter 14 – Electric Current and Its Effects- Complete Notes
Also Check- Batteries- The Powerhouses of Everyday Life – A Guide for Upper Primary Students
