A parallel plate capacitor is charged to a potential difference of $100\,V$ and disconnected from the source of $emf$. A slab of dielectric is then inserted between the plates. Which of the following three quantities change?
$(i)$ The potential difference $(ii)$ The capacitance $(iii)$ The charge on the plates
only $(i)$ and $(ii)$
only $(i)$ and $(iii)$
only $(ii)$ and $(iii)$
All $(i),\, (ii)$ and $(iii)$
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 similarly charged to a potential difference $2V$ . The charging battery is now disconnected and the capacitors are connect 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 point charge $'q'$ is placed at a point inside a hollow conducting sphere. Which of the following electric force pattern is correct ?
An electric dipole of dipole moment $\vec P$ is lying along a uniform electric field $\vec E$ . The work done in rotating the dipole by $90^o$ is
If the charge on a capacitor is increased by $2\, C$ the energy stored in it increases by $21\%$. The original charge on the capacitor (in coulomb) is
The value of electric potential at any point due to any electric dipole is