Mihael Makek

For two hundred years—ever since Faraday’s first conception of the field lines—hearts and minds of students have been pervaded by erroneous and unsubstantiated claims about these well defined mathematical objects. The most prominent misconceptions include: (1) a notion of the field lines as of ‘lines of force’; (2) a notion that the field lines coincide with particle trajectories; (3) a notion that a field line density measures a magnitude of a vector field; (4) a notion that the field lines of a divergence-free field always form closed loops. Even the modern day literature systematically perpetuates some of these claims. We compile here the trivial counterexamples to these claims, providing physics instructors with an efficient and effective way of dispelling these misconceptions.

We present a simple setup for the measurement of the magnetic moment of cosmic muons convenient for a student laboratory experiment. A significant simplification is made in the detector system compared to previous experiments of this kind, yet it retains all the necessary functionality of the system. This simplification additionally allows for the use of low-cost custom-made electronics for data readout and storage. These improvements considerably reduce the cost and provide a more accessible setup for a student laboratory experiment.