The magnetic field 0.02 m from a wire is 0.1 T. What is the magnitude of the magnetic field 0.01 m from the same wire?

The magnetic field at 0.01m from the wire is 0.2T.

Explanation:

The magnetic field at a distance due to a straight wire carrying a current is

where is the magnetic constant.

Now, we are told that the magnetic field from a wire at is ; therefore,

solving for we get:

which is the current through the wire.

Now, the magnetic field of the wire due to this current at the distance of is

Thus, the magnetic field at 0.01m from the wire is 0.2T.

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