(i) Positive charge will be produced on glass rod and negative charge will be produced on silk. The electrons are less tightly bound in glass rod as compared to silk.

(ii) Negative charge will be produced on ebonite rod and positive charge will be produced on wool.

Here given the particles have an equal charge joined by a string of length 1 m.

                   $$\begin{gathered} {\mathrm{q}}_1 = {\mathrm{q}}_2 = 2 \times {10}^{-8}\mathrm{C} \\ \mathrm{r} = 1 \mathrm{m} \end{gathered}$$

Tension in the string is the force of repulsion (F) between the two charges.

According to Coulomb's law,
                 $$\begin{gathered} \mathrm{F} = \frac{{\mathrm{q}}_1 {\mathrm{q}}_2}{4\mathrm{\pi } {\in }_0 {\mathrm{r}}^2} \\ =\frac{9 \times {10}^9 (2 \times {10}^{-8}) (2 \times {10}^{-8})}{1^2} \end{gathered}$$
         
                 $\mathrm{F} = 3.6 \times {10}^{-6}\mathrm{N}$