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

Charges +q and $$-$$q are placed at points A and B respectively which are a distance 2L apart, C is the midnight between A and B. The work done in moving a charge + Q along the semicircle CRD is

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

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