Consider two point charges of equal magnitude and opposite sign separated by a certain distance. The neutral point due to them

Four charges equal to $-Q$ are placed at the four corners of a square and a charge $q$ is at its centre. If the system is in equilibrium the value of $q$ is

Three points charges are placed at the corners of an equilateral triangle of side $L$ as shown in the figure.

The distance between charges $5 \times {10^{ - 11}}\,C$ and $ - 2.7 \times {10^{ - 11}}\,C$ is $0.2\, m$. The distance at which a third charge should be placed in order that it will not experience any force along the line joining the two charges is......$m$

A point charge of $40$ stat coulomb is placed $2$ $cm$ in front of an earthed metallic plane plate of large size. Then the force of attraction on the point charge is.....$dynes$

Three charges $ - {q_1},\,\, + {q_2}$ and $ - {q_3}$ are placed as shown in the figure. The $x$-component of the force on $ - {q_1}$ is proportional to