Two identical conducting spheres carry identical charges. If the spheres are set at a certain distance apart, they repel each other with a force $F$. A third conducting sphere identical to the other two, but initially uncharged is touched to one sphere and then to the other before being removed. The force between the original two spheres is now
$\frac{F}{2}$
$\frac{F}{4}$
$\frac{3 F}{4}$
$\frac{3 F}{8}$
Two charges placed in air repel each other by a force of ${10^{ - 4}}\,N$. When oil is introduced between the charges, the force becomes $2.5 \times {10^{ - 5}}\,N$. The dielectric constant of oil is
Two identical conducting spheres having unequal positive charges $q_1$ and $q_2$ separated by distance $r$. If they are made to touch each other and then separated again to the same distance, the electrostatic force between them in this case will be :-
Two particle of equal mass $m$ and charge $q$ are placed at a distance of $16\, cm$. They do not experience any force. The value of $\frac{q}{m}$ is
Three point charges $q_1, q_2, q_3$ are placed at the vertices of a triangle if force on $q_1$ and $q_2$ are $\left( {2\hat i - \hat j} \right)\,N$ and $\left( {\hat i + 3\hat j} \right)\,N$, respeactively, then what will be force on $q_3$ ?
In hydrogen like system the ratio of coulombian force and gravitational force between an electron and a proton is in the order of: