Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Motion of a superconducting loop in an inhomogeneous magnetic field: a
  didactic experiment   We present an experiment conductive to an understanding of both Faraday's law
and the properties of the superconducting state. It consists in the analysis of
the motion of a superconducting loop moving under the influence of gravity in
an inhomogeneous horizontal magnetic field. Gravity, conservation of magnetic
flux, and friction combine to give damped harmonic oscillations. The measured
frequency of oscillation and the damping constant as a function of the magnetic
field strength (the only free parameter) are in good agreement with the
theoretical model.

16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci