Three point charges +q, $$-$$ 2q and + q are placed at points (x = 0, y = a, z = 0), (x = 0, y = 0, z = 0) and (x = $$a$$, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are

A hollow cylinder has a charge q coulomb within it. If $$f$$ is the electric flux in units of voltmeter associated with the curved surface B, the flux linked with the plane surface A in units of V-m will be

An electric dipole of moment $$\overrightarrow p $$ is lying along a uniform electric field $$\overrightarrow E $$. The work done in rotating the dipole by 90^o is

A square surface of side L metres is in the plane of the paper. A uniform electric field $$\overrightarrow E $$ (volt/m), also in the plane of the paper is limited only to the lower half of the square surface (see figure). The electric flux in SI inits associated with the surface is