Three charges $4q,\,Q$ and $q$ are in a straight line in the position of $0$, $l/2$ and $l$ respectively. The resultant force on $q$ will be zero, if $Q = $
$-q$
$ - \,2q$
$ - \frac{q}{2}$
$4q$
A capacitor is charged by using a battery which is then disconnected. A dielectric slab is then slipped between the plates, which results in
A point charge $'q'$ is placed at a point inside a hollow conducting sphere. Which of the following electric force pattern is correct ?
An insulator plate is passed between the plates of a capacitor. The the displacement current
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 dielectric has dielectric constant $K_1 = 6$ and thickness $\frac {d}{3}$ while the other one has dielectric constant $K_2 = 12$ and thickness $\frac {2d}{3}$ . Capacitance of the capacitor is now ......... $pF$
The amount of heat liberated in the circuit after closing the switch $S$ .