Magnetic Field from Two Parallel Wires (Physics II)?
Two straight parallel wires carry currents in opposite directions as shown in the figure. One of the wires carries a current of I2 = 10.5 A. Point A is the midpoint between the wires. The total distance between the wires is d = 12.6 cm. Point C is 4.02 cm to the right of the wire carrying current I2. Current I1 is adjusted so that the magnetic field at C is zero.
IMAGE: http://i40.tinypic.com/1ovmtg.gif
a) Calculate the value of the current I1.
b) Calculate the magnitude of the magnetic field at point A.
c) What is the force between two 1.45 m long segments of the wires?
I already got part a to be 43.4 A but can't get b and c. Any help is appreciated!
Comments
For b) you could find the magnetic field from each wire by themselves (ampere's law), and add them via superpositioning principle.
For c) I would use F = I L x B
actually I'm not sure what c) is asking for really, but if it's asking for the magnetic force on one wire by the other wire, and both wires are 1.45m long and placed side by side, then this could be quite complicated. First you would have to express B as a function of the vertical position, since we're not dealing with infinitely long wires, the B-field varies with vertical position. Then you would have to integrate along the vertical wire, that is you integrate I dL x B, over the length of one wire.