Magnetic Field of a Coil

# Magnetic Field of a Coil - magnetic field can be mapped out...

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Magnetic Field of a Coil Theory: A coil of wire carrying a magnetic field produces a magnetic field B(r) with r being the distance from the center of the coil. The strength of the field is proportional to the current I in the coil and the strength and direction of the field depend on r. We measured the magnetic field for distances fairly close to the coil. A magnetic field can be described by a vector B whose direction indicates the direction of the field and whose length is proportional to the magnitude of the magnetic field. To determine the presence of magnetic field we used the principle of Faraday Induction or Electromagnetic Induction, which states that a magnetic field that varies with time produces an electric field. This electric field will produce a current and voltage in a coil of wire. By measuring this voltage and current for different orientations of a small coil the time varying
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Unformatted text preview: magnetic field can be mapped out. The current producing the magnetic field will be varied sinusoidally in time so that the induction technique indicates amplitude and direction of the magnetic field at various points in space. The frequency of the sinusoidal current will be set low so the magnetic field mapped will be essentially the same as the field produced by a coil carrying a steady current, which produces a steady magnetic field. In a coil of wire, as in all other shapes of wire with current, the magnetic field at any position is equal to the sum of contributions from the many short elementsof wire composing the entire length of the wire. For a coil, the contributions of the short elements add together to produce a greater field within the coil, along its axis, based on symmetry. The field in the central region is strong and uniform...
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## This note was uploaded on 09/23/2008 for the course PHYS 0095 taught by Professor Budick during the Spring '07 term at NYU.

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