Electric flux through surface $s_1$

In the circuit, shown in the figure, the effective capacitance between $A$ and $B$ is......$\mu F$

A parallel plate capacitor is charged to a potential difference of $100\,V$ and disconnected from the source of $emf$. A slab of dielectric is then inserted between the plates. Which of the following three quantities change?

$(i)$ The potential difference    $(ii)$ The capacitance    $(iii)$ The charge on the plates

Electric field at a place is $\overrightarrow E  = {E_0}\widehat i\,\,V/m$. A particle of charge $+q_0$ moves from point $A$  to $B$ along a circular path find work done in this motion by electric field :-

If on the concentric hollow spheres of radii $r$ and $R( > r)$ the charge $Q$ is distributed such that their surface densities are same then the potential at their common centre is

The energy stored in the capacitor is $'U'$. If an uncharged capacitor of same capacity is connected in parallel with it, then energy stored in each capacitor is