A torroid has a core outer radius $26\;cm$ around which 3500 turns of a wire are wound . If the current in the wire is $11\;A$ , What is the magnetic field, inside the core of the torriod .

Question

$\begin{array}{1 1} 3.02 \times 10^{-3}T \\ 3.02 \times 10^{-2}T \\ 3.02 \times 10^{-4}T \\ 3.02 \times 10^{-1}T \end{array} $