单词 | magnetic field |
释义 | magnetic field A field of force that exists around a magnetic body (see magnetism) or a current-carrying conductor. Within a magnetic field a magnetic dipole may experience a torque and a moving charge may experience a force. The strength and direction of the field can be given in terms of the magnetic flux density (or magnetic induction ), symbol B; it can also be given in terms of the magnetic field strength (magnetizing force or magnetic intensity ), symbol H. The magnetic flux density is a vector quantity and is the magnetic flux per unit area of a magnetic field at right angles to the magnetic force. It can be defined in terms of the effects the field has, for example by B = F/qvsinθ , where F is the force a moving charge q would experience if it was travelling at a velocity v in a direction making an angle θ with that of the field. The SI unit is the tesla.The magnetic field strength is also a vector quantity and is related to B by: H = B/µ where µ is the permeability of the medium. The SI unit of field strength is the ampere per metre (A m-1) |
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