Physics Question from JEE Main 2023 · 1 February, Shift 2

A block is fastened to a horizontal spring. The block is pulled to a distance $x = 10 \, \text{cm}$ from its equilibrium position (at $x = 0$) on a frictionless surface from rest. The energy of the block at $x = 5 \, \text{cm}$ is $0.25 \, \text{J}$. The spring constant of the spring is _____ $\text{N m}^{-1}$.