A solenoid has 150 turns wound over a
former that is 10 cm long and is of uniform circular cross-section
diameter 3.0 cm. A current of 5.6 A flows through it.
Calculate the flux that it produces.

F = m_{0}AnI

A = p ×
(1.5 × 10^{-2} m)^{2} = 7.069 × 10^{-4} m^{2}

n = 150 ÷ 0.10 m = 1500 m^{-1}

F = 4p
× 10^{-7} H m^{-1} × 7.069 × 10^{-4} m^{2}
× 1500 m^{-1} × 5.60 A