A coil of 20 closely wound turns is shaped into a circle of radius

PHYSICS · Subjective · AP · Physics C: Electricity and Magnetism · Magnetic Fields and Electromagnetism · Magnetic Fields and Electromagnetism

Problem

10\,\text{cm}

. What current must flow through the coil so that the magnetic field at its centre is

1.0\times10^{-4}\,\text{T}

? Give your answer to two significant figures.