$A$ conducting sphere of radius $R$ carrying a charge $q$ is joined by a conducting wire to a conducting sphere of radius $2R$ carrying a charge $-2q$. The charge flowing between them will be:

Two insulated metallic spheres of $3\,\mu F$ and $5\,\mu F$ capacitances are charged to $300\, V$ and $500\, V$ respectively. The energy loss,when they are connected by a wire,is (in $,J$)

$A$ $10\,\mu F$ capacitor and a $20\,\mu F$ capacitor are connected in series across a $200\,V$ supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together,and no external voltage is applied. What is the potential difference across each capacitor?

There are two identical capacitors. The first one is uncharged and filled with a dielectric of constant $K$,while the second one is charged to potential $V$ and has air between its plates. If the two capacitors are joined in parallel,the common potential will be:

Two metal spheres have radii of $20\, cm$ and $10\, cm$ respectively, and each sphere carries a charge of $150\, \mu C$. After connecting them with a conducting wire, the common potential on them will be:

Two metallic charged spheres whose radii are $20\,cm$ and $10\,cm$ respectively,have each $150\,\mu C$ positive charge. The common potential after they are connected by a conducting wire is