Consider a uniformly charged hemispherical shell having charge per unit area $\sigma$. Find potential (in Volts) at point P due to the shell, R is the radius of shell. The distance of point P from the centre is R/2 (see diagram).  $\left[\text{Given\hspace{0.17em}}\frac{\text{σR}}{{\text{ε}}_{\text{0}}}\text{=4\hspace{0.17em}SI\hspace{0.17em}units}\right]$