Electric Charge...

When two charges are equal q each, force they exert on each other is $$F$$. When one of the charges is doubled, the $$2$$q charge exerts a force $$2F$$ on charge q. The force exerted by q on $$2$$q is :

Two charged particles each of mass $$5$$g and charge $$q=2\mu C $$ are suspended as shown in the figure. The system is taken in a satellite. The force between the charges is:

A charge Q is divided into two parts. The two charges kept at a distance apart have a maximum columbian repulsion. Then the ratio of Q and one of the parts is given by :

The field at a distance r from a long string of charge per unit length $$\lambda$$ is :

A charge Q is divided into two parts q and Q - q and separated by a distance R. The force of repulsion between them will be maximum when

In a certain region of space, there exists a uniform electric field of $$2\times 10^{3} \hat {k}\  Vm^{-1}$$. A rectangular coil of dimension $$10\ cm\times 20\ cm$$ is placed in $$x - y$$ plane. The electric flux through the coil is

In comparison to the electrostatic force between two electrons, the electrostatic force between two proton is :

The sign of each charge $$Q_1$$ and $$Q_2$$ is:

Two identical conducting small spheres are placed with their centres $$0.3 m$$ apart. One is given a charge of $$12.0 nC$$ and the other a charge of $$-18.0 nC$$. Find the electric force exerted by one sphere on the other?

A cylinder of length $$L$$ and radius $$b$$ has its axis coincident with the x-axis. The electric field in this region is $$\vec {E} = 200\hat {i}$$. Find the flux through the left end of cylinder.