Electric Charge...

A charge q is to be distributed on two conducting spheres. What should be the value of the charges on the spheres so that the repulsive force between them is maximum when they are placed at a fixed distance from each other in air?

A charge $$+q$$ having mass $$m$$ is released from rest in a uniform electric field $$E$$ momentum acquired by the charge after time $$t$$ is:

A plane surface of area $$10\ cm^{2}$$ is placed in a uniform electric field of $$20\ N/C$$ such that the angle between the surface and the electric field is $$30^{o}$$. The electric flux over the surface is:

A  wire of linear charge density $$\lambda$$ passes through a cuboid of length $$\ell$$, breadth $$b$$ and height $$h\ (\ell>b>h)$$ in such a manner that flux through the cuboid is maximum. The position of the wire is now changed, so that the flux through the cuboid is minimum. The ratio of maximum flux to minimum flux will be :

Two points charges $$+\ 9e$$ and $$+e$$ are kept $$16\ cm$$ apart to each other. Where a third charge $$q$$ is placed between them so that the system is in the equilibrium state-

Force of attraction between two point electric charges placed at a distance d in a medium is F. What distance apart should these be kept in the same medium, so that force between them becomes $$\frac{F}{3}$$?

An electron enters an electric field with its velocity in the direction of the electric lines of field then:

There are two charges $$+1\mu$$  and $$+5\mu$$ . The ratio of the forces acting on them will be

In the fig. force on charge at $$A$$ in the direction normal to $$BC$$ will be:

Charges $$\theta_1$$ and $$\theta_2$$ lie inside and out side respectively for a closed surface s. Let E be the field at a point on S and $$\phi$$ be flux of E over S