A parallel plate capacitor $\mathrm{C}$ with plates of unit area and separation $\mathrm{d}$ is filled with a liquid of dielectric constant $\mathrm{K}=2$. The level of liquid is $\frac{\mathrm{d}}{3}$ initially. Suppose the liquid level decreases at a constant speed $V,$ the time constant as a function of time $t$ is Figure: $Image$
$\frac{6 \varepsilon_0 \mathrm{R}}{5 \mathrm{~d}+3 \mathrm{Vt}}$
$\frac{(15 \mathrm{~d}+9 \mathrm{Vt}) \varepsilon_0 \mathrm{R}}{2 \mathrm{~d}^2-3 \mathrm{dVt}-9 \mathrm{~V}^2 \mathrm{t}^2}$
$\frac{6 \varepsilon_0 \mathrm{R}}{5 \mathrm{~d}-3 \mathrm{Vt}}$
$\frac{(15 \mathrm{~d}-9 \mathrm{Vt}) \varepsilon_0 \mathrm{R}}{2 \mathrm{~d}^2+3 \mathrm{dVt}-9 \mathrm{~V}^2 \mathrm{t}^2}$
Condenser $A$ has a capacity of $15\,\mu F$ when it is filled with a medium of dielectric constant $15$. Another condenser $B$ has a capacity of $1\,\mu F$ with air between the plates. Both are charged separately by a battery of $100\;V$. After charging, both are connected in parallel without the battery and the dielectric medium being removed. The common potential now is.....$V$
Assertion : A parallel plate capacitor is connected across battery through a key. A dielectric slab of dielectric constant $K$ is introduced between the plates. The energy which is stored becomes $K$ times.
Reason : The surface density of charge onthe plate remains constant or unchanged.
Separation between the plates of a parallel plate capacitor is $d$ and the area of each plate is $A$. When a slab of material of dielectric constant $k$ and thickness $t(t < d)$ is introduced between the plates, its capacitance becomes
A capacitor of capacity $'C'$ is connected to a cell of $'V'\, volt$. Now a dielectric slab of dielectric constant ${ \in _r}$ is inserted in it keeping cell connected then
Three capacitors $A,B$ and $C$ are connected with battery $emf\, \varepsilon $. All capacitors are identical initially. If dielectric slab is inserted between plates of capacitor $A$ slowy with help of external force then