Consider a thin spherical shell of radius $R$ with its centre at the origin, carrying uniform positive surface charge density. The variation of the magnitude of the electric field $|\vec{E}(r)|$ and the electric potential $V(r)$ with the distance r from the centre, is best represented by which graph?

$N$ identical spherical drops charged to the same potential $V$ are combined to form a big drop. The potential of the new drop will be

Two insulated charged conducting spheres of radii $20\,cm$ and $15\,cm$ respectively and having an equal charge of $10\,C$ are connected by a copper wire and then they are separated. Then

The radius of a charged metal sphere $(R)$ is $10\,cm$ and its potential is $300\,V$. Find the charge density on the surface of the sphere

The electric field in a region surrounding the origin is uniform and along the $x$ - axis. A small circle is drawn with the centre at the origin cutting the axes at points $A, B, C, D$ having co-ordinates $(a, 0), (0, a), (-a, 0), (0, -a)$; respectively as shown in figure then potential in minimum at the point

Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is