Tesla (unit) Tesla (unit) The tesla (symbol T) is a derived unit of the magnetic field strength (also, magnetic flux density) in the International System of Units. One tesla is equal to one weber per square metre. The unit was announced during the General Conference on Weights and Measures in 1960 and is named in honour of Nikola Tesla, upon the proposal of the Slovenian electrical engineer France Avčin. The strongest fields encountered from permanent magnets are from Halbach spheres and can be over 4.5 T. The record for the highest sustained pulsed magnetic field has been produced by scientists at the
Spectral flux density In a region in which the material is uniform and the radiative field is isotropic and homogeneous, let the spectral radiance (or specific intensity) be denoted by , a scalar-valued function of its arguments , , , and , where denotes a unit vector with the direction and sense of the geometrical vector from the source point to the detection point , where denotes the coordinates of , at time and wave frequency . Then, in the region, takes a constant scalar value, which we here denote by . In this case, the value of the vector flux density at