When air is replaced by a dielectric medium of constant $k$, the maximum force of attraction between two charges separated by a distance
become ${k^{ - 1}}$ times
Remains unchanged
Increases $k$ times
become ${k}$ times
A charge ${q_1}$ exerts some force on a second charge ${q_2}$. If third charge ${q_3}$ is brought near, the force of ${q_1}$ exerted on ${q_2}$
Why is an electric force conservative ?
$ABC$ is a right angled triangle in which $AB = 3\,cm$ and $BC = 4\,cm$. And $\angle ABC = \pi /2$. The three charges $ + 15,\; + 12$ and $ - 20\,e.s.u.$ are placed respectively on $A$, $B$ and $C$. The force acting on $B$ is.......$dynes$
Three charge $q$, $Q$ and $4q$ are placed in a straight line of length $l$ at points distant $0,\,\frac {l}{2}$ and $l$ respectively from one end. In order to make the net froce on $q$ zero, the charge $Q$ must be equal to
Two free positive charges $4q$ and $q$ are a distance $l$ apart. What charge $Q$ is needed to achieve equilibrium for the entire system and where should it be placed form charge $q$ ?