The magnetic field at the center of a 1.0-cm-diameter loop is 2.5 mT. a. What is the current in the loop? b. A long straight wire carries the same current you found in part a. At what distance from the wire is the magnetic field 2.5 mT?

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

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