The magnetic potential energy ($U$) stored in an inductor is given by the formula: $U = \frac{1}{2} L I^2$

Given: Self-inductance ($L$) = $10 \text{ H}$ Current ($I$) = $1 \text{ A}$

Calculation: $U = \frac{1}{2} \times 10 \times (1)^2$ $U = 5 \times 1$ $U = 5 \text{ J}$