Pressure in a liquid is divided equally so we can say pressure at both the pistons should be same

\(\Rightarrow \frac{F_1}{A_1}=\frac{F_2}{A_2}\)   \(\left\{\begin{array}{l}\text { Where, } \\ F_1=F \\ A_1=10 \,cm ^2 \\ A_2=10 \,m ^2=10 \times 10^4 \,cm ^2 \\ F_2=8000 \,N \end{array}\right.\)

Substituting values,

\(\frac{F}{10}=\frac{8000}{10 \times 10^4}\)

\(\Rightarrow F=0.8 \,N\)   \(\left\{\begin{array}{l}\text { Take } \\ g=10 \,m / s ^2\end{array}\right\}\)