Induction and the Earth's magnetic field¶
A changing magnetic flux creates a measurable electric current in a loop of wire. One way of creating a change in magnetic flux is by changing the orientation of the loop with respect to a constant field . In this experiment, the strength and orientation of the Earth’s magnetic field is measured by observing the electrical response produced during a rotation of a coil of wire (known as the -flipper). Because the Earth’s magnetic field is relatively weak, an op-amp circuit is used to amplify the signal.
Experiment in a nutshell¶
A changing magnetic flux will induce a current: it is known. Rotating a coil in a constant magnetic field will produce a change in magnetic flux, and by measuring the induced current, one can infer the strength of the static field. In principle, the experiment is straightforward, but some worthwhile considerations:
- Consider carefully the orientation of the coil and its axis of rotation
- Determine how one can assess the effect of any drift on the integrator
- Take a set a measurements, a carefully quantify the spread of these results and qualify the origin of the spread
- The origin of magnetic fields is an important: for where do they come, and what are the implications for your experiment?
Additional resources¶