A parallel plate capacitor with air between the plates has a capacitance of $9\, pF$. The separation between its plates is $'d'$. The space between the plates is now filled with two dielectrics. One of the dielectrics has dielectric constant $K_1=3$ and thickness $\frac{d}{3}$ while the other one has dielectric constant $K_2 = 6$ and thickness $\frac{2d}{3}$ . Capacitance of the capacitor is now.........$pF$
$1.8$
$45$
$40.5$
$20.25$
A given charge situated at a distance $r$ from an electric dipole on it axis experiences a force $F$. If the distance of the charge from the dipole is doubled, the force acting on the charge will be
Charge $q$ is uniformly distributed over a thin half ring of radius $R$. The electric field at the centre of the ring is
A solid spherical conducting shell has inner radius a and outer radius $2a$. At the center of the shell a point charge $+Q$ is located . What must the charge of the shell be in order for the charge density on the inner and outer surfaces of the shell to be exactly equal?
An infinite number of identical capacitors each of capacitance $1 \mu F$ are connected as shown in the figure. Then, the equivalent capacitance between $A$ and $B$ is .......... $\mu F$
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