Educator

Magnetic Field Produced By Current, Part 3

• Two parallel conductors, carrying currents, attract if the currents are parallel, and repel if the currents are antiparallel. The force is a magnetic force. Basically, one wire produces a magnetic field, which, in turn, exerts a force on the other wire.
• Magnetic flux: If a uniform magnetic field B exists in space, then the magnetic flux through a surface, of area A, placed perpendicular to the field, is BA. If the normal to the plane surface makes an angle theta with B, then the magnetic flux through the surface is BAcos(theta). For a general case when either B is not uniform, and/or the surface is not flat, the flux is the integral of B.da over the surface.
• Gauss’s law in magnetism: The magnetic flux through any closed surface is zero.