1 The following materials are required for determining the magnetic flux index:
(a) a direct current field Gauss meter with a resolution of 0.0005 T that is capable of determining the flux density of the magnetic field to a minimum accuracy of 1.5% and that has an axial type probe with an active area diameter of 0.76 ± 0.13 mm that is at a distance of 0.38 ± 0.13 mm from the probe tip; and
(b) a caliper or similar device for measuring dimensions to a minimum accuracy of 0.1 mm.
2 The following method is to be used for determining the magnetic flux index:
(a) place the Gauss meter probe tip perpendicularly against the surface of the magnetic toy or the magnetic component and slowly move the probe across the entire surface to locate the maximum absolute value of the flux density;
(b) record the maximum absolute value of the flux density in tesla;
(c) extract the magnet by breaking the magnetic toy or magnetic component, if necessary, without damaging the magnet;
(d) calculate in square millimetres the area of the biggest pole surface of the magnet using the geometric formula for the surface area that corresponds to the shape of the surface:
(i) if the pole surface is flat, measure the dimensions with an accuracy of ± 0.1 mm,
(ii) if the pole surface is not flat, as in (i), measure the dimensions of the maximal cross-section that is perpendicular to the axis that goes through the magnet poles with an accuracy of ± 0.1 mm,
(iii) if the magnet is a multi-pole magnet, measure the dimensions of the largest single pole, which can be identified using magnetic field viewing film or an equivalent method;
(e) square the maximum absolute value of the flux density and multiply it by the area of the biggest pole surface of the magnet to obtain the magnetic flux index, expressed in tesla squared millimetre squared.
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