Calculate the magnetic field at the center due to one loop:
\[ B = \frac{\mu_0 I}{2a} \]
Since there are two loops in perpendicular planes, the resultant magnetic field is:
\[ B_{\text{net}} = \sqrt{B^2 + B^2} = \frac{\mu_0 I}{\sqrt{2}a} \]
Let $ P_n = \alpha^n + \beta^n $, $ n \in \mathbb{N} $. If $ P_{10} = 123,\ P_9 = 76,\ P_8 = 47 $ and $ P_1 = 1 $, then the quadratic equation having roots $ \alpha $ and $ \frac{1}{\beta} $ is: