A cylindrical rod of length 1 m and radius 4 cm is mounted vertically. It is subjected to a shear force of $10^5 \mathrm{~N}$ at the top. Considering infinitesimally small displacement in the upper edge, the angular displacement $\theta$ of the rod axis from its original position would be: (shear moduli, $\left.\mathrm{G}=10^{10} \mathrm{~N} / \mathrm{m}^2\right)$