Equal charges $q$ are placed at the four corners $A,\,B,\,C,\,D$ of a square of length $a$. The magnitude of the force on the charge at $B$ will be
$\frac{{3{q^2}}}{{4\pi {\varepsilon _0}{a^2}}}$
$\frac{{4{q^2}}}{{4\pi {\varepsilon _0}{a^2}}}$
$\left( {\frac{{1 + 2\sqrt 2 }}{2}} \right)\frac{{{q^2}}}{{4\pi {\varepsilon _0}{a^2}}}$
$\left( {2 + \frac{1}{{\sqrt 2 }}} \right)\frac{{{q^2}}}{{4\pi {\varepsilon _0}{a^2}}}$
Write limitations of Coulomb’s law.
A charged particle with charge $q$ and mass $m$ starts with an initial kinetic energy $K$ at the middle of a uniformly charged spherical region of total charge $Q$ and radius $R$ . $q$ and $Q$ have opposite signs. The spherically charged region is not free to move . The value of $K_0$ is such that the particle will just reach the boundary of the spherically charged region. How much time does it take for the particle to reach the boundary of the region.
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
The law, governing the force between electric charges is known as
Two charges each equal to $2\,\mu C$ are $0.5\,m$ apart. If both of them exist inside vacuum, then the force between them is.......$N$