Here, `N = 200, L = 10 mH = 10 xx 10^(-3) H`,
`I = 4 mA = 4 xx 10^(-3) A , phi = ?`
Total magnetic flux linked with the coil `phi = `
`NLI = 200 xx (10 xx 10^(-3)) xx 4 xx 10^(-3) = 8 xx 10^(-3) Wb`
Magnetic flux through the cross-section of the coil = magnetic flux linked with each turn
`=(phi)/(N) = (8 xx 10^(-3))/(200) = 4 xx 10^(-5) Wb`