Magnetic fields around electric currents

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C16  Magnetic fields around electric currents I–straight wire (TAS)


To use a search coil and CRO to investigate the magnetic field due to a straight wire carrying an a.c..


In this experiment, a search coil is used to measure strength of magnetic field.For a long straight wire carrying current I ,there will be a magnetic field induced around the wire, given by .

Results and discussion

7        Why is this necessary to ensure the search coil is at the same level as the wire?

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If there is inclination between the search coil and the wire, there will be a component of

the magnetic field formed. The horizontal component of the magnetic field will be

measured. This is not the maximum magnetic field that we want.

8        Why the sensitivity of the search coil can be increased by increasing the frequency?

The more frequent the voltage across the wire, the more frequent is the change of the

magnetic field. The magnetic field  across the search coil is proportional to the sensitivity.

9        Tabulate the length l of vertical trace ...

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