Tesla (unit) One tesla is equivalent to: One tesla is equal to 1 V·s/m. This can be shown by starting with the speed of light in vacuum, "c" = (εμ), and inserting the SI values and units for "c" (), the vacuum permittivity ε (), and the vacuum permeability μ (). Cancellation of numbers and units then produces this relation. For the relation to the units of the magnetising field (ampere per metre or Oersted), see the article on permeability. Tesla (unit) The tesla (symbol T) is a derived unit of the magnetic field strength (also, magnetic flux density) in the International
Spectral flux density in the vertical direction, and the downward sense in that direction. This investigator thinks of a unit area in a horizontal plane, surrounding the prescribed point. The investigator wants to know the total power of all the radiation from the atmosphere above in every direction, propagating with a downward sense, received by that unit area. For the flux density scalar for the prescribed direction and sense, we may write where with the notation above, formula_12 indicates that the integration extends only over the solid angles of the relevant hemisphere, and formula_13 denotes the angle between formula_6 and the prescribed direction.