An electric dipole consisting of two opposite charges of $$2 \times 10^{-6} \mathrm{C}$$ separated by a distance of $$3 \mathrm{~cm}$$ placed in an electric field of $$2 \times 10^5 \mathrm{~N} / \mathrm{C}$$ then the maximum torque acting on dipole is

In insulators

Seven identical discs each of mass $$M$$ and radius $$\mathrm{R}$$ are arranged in a hexagonal plane pattern so as to touch each neighbour disc as shown in the figure. The moment of inertia of the system of seven discs about an axis passing through the centre of central disc and normal to the plane of all discs is

A satellite moves in a stable circular orbit round the earth if (where $$\mathrm{V}_{\mathrm{H}}, \mathrm{V}_{\mathrm{c}}$$ and $$\mathrm{V}_{\mathrm{e}}$$ are the horizontal velocity, critical velocity and escape velocity respectively)