Three charges are placed as shown in figure. The magnitude of $q_1$ is $2.00\, \mu C$, but its sign and the value of the charge $q_2$ are not known. Charge $q_3$ is $+4.00\, \mu C$, and the net force on $q_3$ is entirely in the negative $x-$ direction. As per the condition given the sign of $q_1$ and $q_2$ will be

A particle of charge $-q$ and mass $m$ moves in a circle of radius $r$ around an infinitely long line charge of linear density $+\lambda$. Then time period will be given as

(Consider $k$ as Coulomb's constant)

Three point charges of magnitude $5 \mu C , 0.16 \mu C$ and $0.3 \mu C$ are located at the vertices $A , B , C$ of a right angled triangle whose sides are $AB =3\,cm$, $BC =3 \sqrt{2}\,cm$ and $CA =3\,cm$ and point $A$ is the right angle corner. Charge at point $A$ experiences

$N$ of electrostatic force due to the other two charges.

Two positive point charges of unequal magnitude are placed at a certain distance apart. A small positive test charge is placed at null point, then

Electric charges of $1\,\mu C,\, - 1\,\mu C$ and $2\,\mu C$ are placed in air at the corners $A$, $B$ and $C$ respectively of an equilateral triangle $ABC$ having length of each side $10 \,cm$. The resultant force on the charge at $C$ is......$N$

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