The aim of the experiment
Determine the horizontal component of the Earth’s magnetic field.
Experiment tools
- Tangent galvanometer
- Ammeter
- Electric switch
- DC power supply
Steps to conduct the experiment
• Connect the devices according to the figure below. The DC supply may have a built-in ammeter and adjustable output.
• Orient the coil perpendicular to the magnetic needle so that the produced field is perpendicular to Earth’s magnetic field.
• Switch on the power supply and adjust the current to the starting value.
• Record the angle θ₁ once the needle stabilizes, then reverse the current and record θ₂. Record all values in Table 1.
• Measure θ₁ and θ₂ for 7–10 current values, compute their averages, and plot tan(θ_avg) versus current I.
• Calculate the horizontal component of Earth’s magnetic field BEarth using the measured values of N and r.
