Magnetic flux through a surface is defined as
- A. B times A times cos theta, where theta is the angle between B and the normal to the surface
- B. B times A times sin theta
- C. B divided by A
- D. B times A only, whatever the orientation
Explanation
Flux counts the field lines threading the surface, so it is greatest when the field is perpendicular to the surface, meaning parallel to its normal, and zero when the field lies in the plane of the surface. Its unit is the weber. Every question on induction depends on tracking how this quantity changes with time.