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)

Find the potential difference between points $x$ and $y$.

In the given circuit, if point $C$ is connected to the earth and a potential of $+2000 \, V$ is applied to point $A$, the potential at point $B$ is.....$V$.

$A$ parallel plate capacitor,after being charged,is kept connected to a battery,and the plates are pulled apart with the help of insulating handles. Which of the following quantities will decrease?

Two capacitors $C_1 = 2 \mu F$ and $C_2 = 4 \mu F$ are connected in a circuit as shown in the figure. The potential difference $(V_A - V_B)$ is....$V$

$A$ composite parallel plate capacitor is made up of two different dielectric materials with different thicknesses ($t_{1} = 0.5 \text{ mm}$ and $t_{2} = 1 \text{ mm}$) and dielectric constants ($\epsilon_{r1} = 3$ and $\epsilon_{r2} = 4$) as shown in the figure. The two dielectric materials are separated by a conducting foil $F$. The voltage of the conducting foil is $.....V$.