[tex]L=10 \ cm \\ l=50 \ mm=5 \ cm \\ h=2,5 \ dm=25 \ cm \\ V_T=L\cdot l\cdot h=10 \ cm \cdot 5 \ cm \cdot 25 \ cm \\ V_T=1 \ 250 \ cm^3 \\ \Rightarrow V_{1/2}=\frac{V_T}{2}=\frac{1\ 250 \ cm^3}{2}=625 \ cm^3 \\ \Rightarrow \boxed{V_{1/2}=0,625 \ l}[/tex]
