8 Marks Questions (8 మార్కుల (ప్రశ్ల)

1. Explain how a compass needle is deflected which is kept near a current carrying metallic conductor
   (Oersted’s experiment)

Oersted’s Experiment

1. Setup:
   • A straight metallic conductor (like a copper wire) is connected to a power source (like a battery) to allow electric current to flow through it.
   • A compass is placed near the conductor, typically at a small distance.
2. Observation:
   • When the electric current flows through the conductor, the compass needle, which normally points towards the Earth’s magnetic north, is observed to deflect from its original position.
3. Explanation of Deflection:
   • The deflection of the compass needle occurs due to the magnetic field generated by the electric current flowing through the conductor.
   • According to Ampère’s circuital law, a current-carrying conductor produces a magnetic field around it. The direction of this magnetic field can be determined using the right-hand rule:
     • If you point your thumb in the direction of the current (from positive to negative), the curl of your fingers shows the direction of the magnetic field lines.
   • The magnetic field produced by the current interacts with the magnetic field of the compass needle. The compass needle itself is a small magnet, and it aligns itself with the magnetic field lines produced by the current.
4. Direction of Deflection:
   • The compass needle will deflect in a direction that aligns with the magnetic field created by the current. The direction of deflection depends on the direction of the current flow:
     • If the current direction is reversed, the direction of the deflection of the compass needle will also reverse.
5. Conclusion:
   • Oersted’s experiment conclusively demonstrated that electric currents produce magnetic fields, establishing a fundamental principle of electromagnetism. This interaction between electricity and magnetism is the basis for many technologies, including electric motors and generators.

Summary