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The wire in the figure below carries a current of 12 A. Suppose that a second lo

ID: 2140033 • Letter: T

Question

The wire in the figure below carries a current of 12 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 26 A. Use Amp

The wire in the figure below carries a current of 12 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 26 A. Use Ampere's law to find the magnitude of the magnetic field at a distance of r = 0.72 m from the wires when the currents are in the same direction and in opposite directions.

Explanation / Answer

magnetic field due to wire at adistance r is

B = ?o I / 2 ? r

current passing through first wire is 12 A

current passing through second wire is 26 A

Distance between point and wire is r = 0.72 m

current passing through wires is same

I = I1 + I2 = 12 +26 = 38 A

magnetic field B = ?o I / 2 ? r

= ( 4 ? *10-7 ) ( 38A ) / 2? ( 0.72 m )

= 1.056 x10-5 T T

Current passing through two wire is in opposite direction

I =26 - 12 = 14 A

B = ?o I / 2 ? r

= ( 4 ? *10-7 ) ( 14 A ) / 2? ( 0.72 m )

= 3.89 x10-6 T