The angle between the electric dipole moment and the electric field strength due to it on the axial line is

A charge $Q$ is enclosed by a Gaussian spherical surface of radius $R$. If the radius is doubled, then the outward electric flux will 

Figure shows three concentric metallic spherical shells. The outermost shell has charge $q_{2}$, the inner most shell has charge $q_{1}$, and the middle shell is uncharged. The charge appearing on the inner surface of outermost shell is