The dielectric strength of air is $E = 3 \times 10^6 \ V/m$. What is the maximum charge that can be given to a sphere of diameter $6 \ m$? (in Coulombs)

$A$ regular hexagon with side length '$a$' is shown. Find the electric field and electric potential at point '$A$'.

In the given electrical circuit,if the switch $S$ is closed,then the maximum energy stored in the inductor is: (in $J$)

$A$ parallel plate capacitor of capacitance $C$ is connected to a battery and is charged to a potential difference $V$. Another capacitor of capacitance $2C$ is connected to another battery and is charged to a potential difference $2V$. The charging batteries are now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is

$A$ capacitor $A$ has a capacitance of $15\ \mu F$ when filled with a dielectric of constant $K = 15$. Another capacitor $B$ is air-filled and has a capacitance of $1\ \mu F$. Both are charged to $100\ V$. After charging, the dielectric is removed from capacitor $A$, and the two capacitors are connected in parallel. The common potential difference across them will be ... $V$.

Plates $A$ and $B$ constitute an isolated,charged parallel-plate capacitor. The inner surfaces ($I$ and $IV$) of $A$ and $B$ have charges $+Q$ and $-Q$ respectively. $A$ third plate $C$ with charge $+Q$ is now introduced midway between $A$ and $B$. Which of the following statements is not correct?