If \(U_n=\left(1+\frac{1}{n^2}\right)\left(1+\frac{2^2}{n^2}\right)^2 \ldots \ldots\left(1+\frac{n^2}{n^2}\right)^n\), t…

If \(U_n=\left(1+\frac{1}{n^2}\right)\left(1+\frac{2^2}{n^2}\right)^2 \ldots \ldots\left(1+\frac{n^2}{n^2}\right)^n\), then \(\lim _{n \rightarrow \infty}\left(U_n\right)^{\frac{-4}{n^2}}\) is equal to :

[JEE Main 2021, 27 Aug (Shift 1)]