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NCERT · Class 10 · Science · Magnetic Effects of Electric CurrentWhat is electromagnetic induction? Explain the experiment conducted by Michael Faraday to demonstrate electromagnetic induction. Also, state Fleming's Right-Hand Rule.

Step-by-Step Solution

Electromagnetic Induction\nThe phenomenon of producing an induced electric current in a closed circuit or a coil due to a changing magnetic field is called electromagnetic induction. It was discovered by Michael Faraday and Joseph Henry.

Faraday's Experiment\nMichael Faraday demonstrated electromagnetic induction using a coil of wire connected to a sensitive galvanometer and a bar magnet.

  1. Setup: A coil containing a large number of turns of insulated copper wire is connected to a galvanometer ($G$). A bar magnet with its North pole facing the coil is held near it.
  2. Case 1 (Moving the magnet towards the coil): When the bar magnet is pushed rapidly towards the coil, the needle of the galvanometer deflects momentarily to one side. This indicates the generation of an electric current in the coil.
  3. Case 2 (Magnet at rest): When the magnet is held stationary inside or near the coil, the galvanometer shows no deflection, proving that current is only induced when there is relative motion.
  4. Case 3 (Moving the magnet away from the coil): When the magnet is pulled away from the coil, the galvanometer deflects in the opposite direction, indicating that the current direction has reversed.
  5. Case 4 (Moving the coil instead of the magnet): Similar deflection is observed if the magnet is kept stationary and the coil is moved towards or away from the magnet.

Conclusion of Experiment\nWhenever there is a relative motion between a conductor/coil and a magnetic field, an induced current is set up in the circuit.

Fleming's Right-Hand Rule

  • Statement: Stretch the thumb, forefinger, and middle finger of your right hand such that they are mutually perpendicular to each other. If the forefinger points in the direction of the magnetic field and the thumb points in the direction of motion (force) of the conductor, then the middle finger will point in the direction of the induced current.
  • Application: It is used to find the direction of induced current in generators.
💡 Study Guide: This question tests core syllabus concepts from Magnetic Effects of Electric Current. For formulas, key summaries, and mock exam reference guides, read the full Magnetic Effects of Electric Current Revision Notes.
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