$h = 0 + \frac{1}{2}(9.8){(2)^2} = 19.6\,m$

$\frac{{\Delta h}}{h} =  \pm 2\left( {\frac{{\Delta t}}{t}} \right)$ $(\because {a = g}$ અચળ$)$   

$ =  \pm 2\left( {\frac{{0.1}}{2}} \right) =  \pm 0.1\,$

$\therefore \Delta h=  \pm \frac{h}{{10}} =  \pm \frac{{19.6}}{{10}}=  \pm 1.96\,m$