Hello,

Magnetic fields are produced by moving electric charges.

S.I unit of Magnetic Field is Tesla .

Tesla measures the magnitude of Magnetic field. It is a vector Quantity

Tesla can be defined as the the strength of magnetic field when a current carrying conductor of 1 metre and carrying current of one ampere current  placed perpendicular to magnetic field.

Hope this was helpful.

Hello Tanu!

The SI unit for magnetic field is the Tesla, which can be seen from the magnetic part of the Lorentz force law F _magnetic = qvB to be composed of (Newton x second)/(Coulomb x meter). A smaller magnetic field unit is the Gauss (1 Tesla = 10,000 Gauss). Notes on units .