The value of electric permittivity of free space is
$9 \times {10^9}\,N{C^2}/{m^2}$
$8.85 \times {10^{ - 12}}\,N{m^2}/{C^2}sec$
$8.85 \times {10^{ - 12}}\,{C^2}/N{m^2}$
$9 \times {10^9}\,{C^2}/N{m^2}$
$A$ and $B$ are two identical blocks made of a conducting material. These are placed on a horizontal frictionless table and connected by a light conducting spring of force constant $‘K’$. Unstretched length of the spring is $L_0$. Charge $Q/2$ is given to each block. Consequently, the spring stretches to an equilibrium length $L$. Value of $Q$ is
Two point charges $Q$ each are placed at a distance $d$ apart. A third point charge $q$ is placed at a distance $x$ from mid-point on the perpendicular bisector. The value of $x$ at which charge $q$ will experience the maximum $Coulomb's force$ is ...............
A certain charge $Q$ is divided into two parts $q$ and $(Q-q) .$ How should the charges $Q$ and $q$ be divided so that $q$ and $(Q-q)$ placed at a certain distance apart experience maximum electrostatic repulsion?
Assertion : Consider two identical charges placed distance $2d$ apart, along $x-$ axis. The equilibrium of a positive test charge placed at the point $O$ midway between them is stable for displacements along the $x-$ axis.
Reason: Force on test charge is zero
Two identical non-conducting thin hemispherical shells each of radius $R$ are brought in contact to make a complete sphere . If a total charge $Q$ is uniformly distributed on them, how much minimum force $F$ will be required to hold them together