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Unformatted text preview: Magnetic Field Generated by Current in Straight Wire (1)
Consider a field point P that is a distance R from the axis of the wire. 0 Idx 0 Idx sin = cos 4 r2 4 r2 R R dx r2 = = 2 2 = x = R tan d cos2 R /r R dB = 0 I 0 I r2 d cos = cos d dB = 2 R 4 r 4 R Z 2 0 I B= cos d 4 R 1 0 I (sin 2 - sin 1 ) = 4 R Length of wire: L = R(tan 2 - tan 1 ) Wire of infinite length: 1 = -90 , 2 = 90 B = 0 I 2R tsl216 p.1/2 Magnetic Field Generated by Current in Straight Wire (2)
Consider a current I in a straight wire of infinite length. The magnetic field lines are concentric circles in planes prependicular to the wire. The magnitude of the magnetic field at distance R 0 I . from the center of the wire is B = 2R The magnetic field strength is proportional to the current I and inversely proportional to the distance R from the center of the wire. The magnetic field vector is tangential to the circular field lines and directed according to the right-hand rule. tsl217 p.2/2 ...
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- Spring '07