Question

Which of the following pairs is correctly matched regarding electromagnetic devices?

• A. Electric Generator: Converts electrical energy to mechanical energy.
• B. Transformer: Operates on DC current to change voltage
• C. Electromagnet: A permanent magnet
• D. Electric Bell: Uses the magnetic effect of electric current.

Answer 1

Answer:

D. Electric Bell: Uses the magnetic effect of electric current.

Electromagnetism and Its Applications

• The Magnetic Effect of Electric Current: Discovered by Hans Christian Oersted in 1820, this principle states that an electric current flowing through a conductor creates a magnetic field around it.
• Electric Bell Mechanism: An electric bell utilizes an electromagnet. When the switch is pressed, the current flows through the circuit, magnetizing the coil. This magnetic force pulls the hammer to strike the gong. As the hammer moves, it breaks the circuit, the electromagnet loses its magnetism, and a spring returns the hammer to its original position, creating a repetitive ringing motion.
• Key Electromagnetic Devices:
  • Electric Motor: Converts electrical energy into mechanical energy using electromagnetic principles.
  • Electric Generator: Works on the principle of Electromagnetic Induction, discovered by Michael Faraday, converting mechanical energy into electrical energy.
  • Relays and Solenoids: Use electromagnetic coils to control switches or move mechanical parts in automotive and industrial systems.
• Factors Affecting Electromagnet Strength: The strength of an electromagnet can be increased by:
  • Increasing the number of turns in the coil.
  • Increasing the amount of current flowing through the conductor.
  • Using a soft iron core inside the coil, which significantly concentrates the magnetic field lines.