A continuous flow settling tank having dimensions $65$ m x $1$ m x $3$ m $($L x B x H$)$ is provided for the treatment of a raw water stream having a flow rate of $2\mathrm{.}5$ x $10^3$ m$^3/$day$.$ Assuming the flow to be laminar, what is the minimum size of particle that can be removed with $100\%$ efficiency in the settling tank? Specific Gravity $($G$)=2\mathrm{.}65,$ Dynamic Viscosity $(\backslash$mu $)=1\mathrm{.}002$ x $10^2$ N$-$s$/$m$^2$