Answer:
A magnetic field is the area surrounding a magnet in which the effects of that magnet may be observed.
A magnetic field is represented by imaginary lines of force which we call magnetic flux (symbol the Greek letter, 'phi'). Flux is measured in units called webers (pronounced 'vay-bers'). Its intensity is called magnetic flux density (B), defined as the flux per unit area, measured in webers per square metre, given the special name tesla.