A parallel plate capacitor has plate area $A$ and separation $d$. It is charged to a potential difference $V_o$. The charging battery is disconnected and the plates are pulled apart to three times the initial separation. The work required to separate the plates is
$\frac{{3{\varepsilon _0}AV_0^2}}{d}$
$\frac{{{\varepsilon _0}AV_0^2}}{{2d}}$
$\frac{{{\varepsilon _0}AV_0^2}}{{3d}}$
$\frac{{{\varepsilon _0}AV_0^2}}{d}$
A $60\; pF$ capacitor is fully charged by a $20\; \mathrm{V}$ supply. It is then disconnected from the supply and is connected to another uncharged $60 \;pF$ capactior is parallel. The electrostatic energy that is lost in this process by the time the charge is redistributed between them is (in $nJ$)
If the plates of a parallel plate capacitor connected to a battery are moved close to each other, then
$A$. the charge stored in it, increases.
$B$. the energy stored in it, decreases.
$C$. its capacitance increases.
$D$. the ratio of charge to its potential remains the same.
$E$. the product of charge and voltage increases.
Choose the most appropriate answer from the options given below:
A parallel plate capacitor having a plate separation of $2\, mm$ is charged by connecting it to a $300\, V$ supply. The energy density is.....$J/m^3$
A capacitor $4\,\mu F$ charged to $50\, V$ is connected to another capacitor of $2\,\mu F$ charged to $100 \,V$ with plates of like charges connected together. The total energy before and after connection in multiples of $({10^{ - 2}}\,J)$ is
A $10\, micro-farad$ capacitor is charged to $500\, V$ and then its plates are joined together through a resistance of $10\, ohm$. The heat produced in the resistance is........$J$