Two similar conducting balls having charges $+q$ and $-q$ are placed at a separation $d$ from each other in air. The radius of each ball is $r$ and the separation between their centres is $d(d > > r)$. Calculate the capacitance of the two ball system
$4 \pi \varepsilon_0 r$
$2 \pi \varepsilon_0$
$4 \pi \log _e \frac{\varepsilon_0 r}{d}$
$4 \pi \log _e \frac{r}{d}$
Sixty-four drops are jointed together to form a bigger drop. If each small drop has a capacitance $C$, a potential $V$, and a charge $q$, then the capacitance of the bigger drop will be
What physical quantities may $X$ and $Y$ represent ? ($Y$ represents the first mentioned quantity)
The capacitance of a spherical condenser is $1\,\mu F$. If the spacing between the two spheres is $1\,mm$, then the radius of the outer sphere is
Two conducting shells of radius $a$ and $b$ are connected by conducting wire as shown in figure. The capacity of system is :
A spherical condenser has inner and outer spheres of radii $a$ and $b$ respectively. The space between the two is filled with air. The difference between the capacities of two condensers formed when outer sphere is earthed and when inner sphere is earthed will be