Measurement of the Earth’s Magnetic Field

Solution:

  1. Apparatus:
    • Magnetic compass
    • Helmholtz coils or solenoid
    • Power supply for Helmholtz coils
    • Protractor or angular measurement device
  2. Procedure:
    • Calibrate the Helmholtz coils to produce a known magnetic field.
    • Place the compass at the center of the Helmholtz coils.
    • Adjust the current in the coils until the compass needle is deflected by 45 degrees.
    • Measure the current and calculate the magnetic field produced by the coils.
    • Use the known field from the coils and the deflection angle to calculate the Earth’s magnetic field.
  3. Calculations:
    • Use the formula Bearth=Bcoiltan⁡(θ)B_{earth} = B_{coil} \tan(\theta), where BcoilB_{coil} is the magnetic field produced by the coils, and θ\theta is the deflection angle.
  4. Error Minimization:
    • Ensure accurate calibration of the Helmholtz coils.
    • Use a precise protractor for angular measurements.
    • Perform the experiment away from magnetic disturbances and repeat multiple times for consistency.