Answer :
The expression for the magnetic field strength from the ampere law when the radius of the hollow wire is considered will be zero.
What is ampere law?
It should be noted that ampere law simply means that for a closed loop path, the magnetic field is proportional to the size of the electric current.
From the complete question, the expression for the magnetic field strength will be zero since the radius is less than R1. In this case, no current is enclosed.
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