Two identical charged spheres separated by a distance $r$ repel each other with a force $F$. If $10 \%$ of electrons are transferred from one sphere to the other,then the force between them becomes

For the regular pentagon system shown in the figure,find the net electrostatic force on the charge $q_0$ placed at the center.

When $4 \ C$,$Q \ C$,and $1 \ C$ electrical charges are placed along a straight line of length $l$ at positions $0$,$\frac{l}{2}$,and $l$ respectively,what are the values of $Q$ such that the net force on the $4 \ C$ charge is zero,and separately,the net force on the $1 \ C$ charge is zero? (in coulomb)

Three identical charges,each $2 \mu C$,lie at the vertices of a right-angled triangle as shown in the figure. Forces on the charge at $B$ due to the charges at $A$ and $C$ respectively are $F_1$ and $F_2$. The angle between their resultant force and $F_2$ is

An electron is moving around the nucleus of a hydrogen atom in a circular orbit of radius $r$. The Coulomb force $\vec{F}$ acting on the electron is given by:

Consider the following charged suspended ball system. If $\alpha < \beta$,then out of the following statements,which can be true at equilibrium? :-
$(a) Q_1 > Q_2, m_1 < m_2$
$(b) Q_1 > Q_2, m_1 > m_2$
$(c) Q_1 < Q_2, m_1 = m_2$
$(d) Q_1 < Q_2, m_1 > m_2$