An infinite, uniformly charged sheet with surface charge density $\sigma$ cuts through a spherical Gaussian surface of radius R at a distance x from its center, as shown in the figure. The electric flux $\mathrm{\Phi }$ through the Gaussian surface is $\frac{\mathrm{k\pi }\left({\mathrm{R}}^2-{\mathrm{x}}^2\right)\mathrm{\sigma }}{{\mathrm{\epsilon }}_0}$. The value of 'k' is