Correct option (a) \(1.0\) henry
Explanation:
For a long solenoid, \(B=\mu_{0} n i=\mu_{0} \frac{N}{l} \cdot i\)
Flux \(=\mu_{0} \frac{N}{l} \cdot i \cdot A\)
given flux per turn \(=4 \times 10^{-3}, i=2 \mathrm{~A}\)
\(\therefore\) Total flux \(=4 \times 10^{-3}\)
\(L=\left(\mu_{0} \frac{N}{l} \cdot N A\right)=\frac{4 \times 10^{-3} \times 500}{2}=1\) henry