Problem:

A wire carries a steady current of 2.4 A.  A straight section of the wire is 0.75 m long and lies along the x-axis within a uniform field B = (1.6k) T.  If the current is in the positive x-direction, what is the magnetic force on the section of wire.

Solution:

• Concepts:
  The Lorentz force on a wire, F =  ∫_V I dlxB(r)
• Reasoning:
  We are asked to find the magnetic force on a section of wire.
• Details of the calculation:
  The force on the wire is given by F = ILxB.

  

  The direction of LxB is the -j direction.  Since L and B are perpendicular to each other
  F = ILB = (2.4 A)(0.75 m)(1.6 T) = 2.88 N.
  The force on the section of wire is F = -2.88 Nj.