Two similar very small conducting spheres having charges $40 \mathrm{\mu }\text{C}$ and $-20 \mathrm{\mu }\text{C}$ are some distance apart. Now they are touched and kept at same distance. The ratio of the initial to the final force between them is,

The magnitude of electric force on $2 \mathrm{\mu C}$ charge placed at the centre $O$ of two equilateral triangles each of side $10 \mathrm{cm}$ as shown in figure is $P$. If charge $A, B, C, D, E$ and $F$ are $2 \mathrm{\mu C}, 2 \mathrm{\mu C}, 2 \mathrm{\mu C}, -2 \mathrm{\mu C}, -2 \mathrm{\mu C} \text{and} -2 \mathrm{\mu C}$ respectively, then $P$ is,