Magnetic Field of ¥ Straight Wire
- Calculate field at distance R from wire using Ampere's Law:
- Ampere's Law simplifies the calculation thanks to symmetry of the current! ( axial/cylindrical )
http://wug.physics.uiuc.edu/courses/phys112/fall97/acts/lect14/act14b/sld001.htm
- Choose loop to be circle of radius R centered on the wire in a plane ^ to wire.
- Why?
- Magnitude of B is constant (fcn of R only)
- Direction of B is parallel to the path.
- Current enclosed by path = I