(T) The system international (SI) unit of magnetic flux density. Definition: 1 T is the field intensity generating 1 N (newton) of force per ampere of current per meter of conductor. The tesla unit value is defined as a field strength of 1 weber per square meter of area, where 1 weber represents 1 x 10⁸ (100 000 000) flux lines. One T is equal to 10 000 gauss, the older (CGS) unit. A field of 1 tesla is quite strong, the Earth's magnetic flux density, at its surface, is about 50 microteslas (µT).