\(\mathrm{Flux}=\mu_{0} \frac{N}{l} \cdot i \cdot A\)
given flux per turn \(=4 \times 10^{-3}, i=2 \,\mathrm{A}\)
\(\therefore \quad\) Total flux \(=4 \times 10^{-3}\)
\(L=\left(\mu_{0} \frac{N}{l} \cdot N A\right)=\frac{4 \times 10^{-3} \times 500}{2}=1\, \mathrm{henry}\)