A closely ward solenoid $80\;cm$ long has $ 5$ layers of winding of 400 turns each.The diameter of the solenoid is $1.8 \;cm$ . If the current carried is $8.0\;A$ , estimate the magnitude of B inside the solenoid near its center .

Question

$\begin{array}{1 1} 2.5 \times 10^{-3}\;T \\ 2.5 \times 10^{-2}\;N \\ 2 \times 10^{-4}\;N \\ 7.1 \times 10^{-2}\;N \end{array} $