The water (H2O) molecule has an electric dipole moment of 6.3 x 10^-30 C · m. A sample contains 10^21 water molecules, with the dipole moments all oriented in the direction of an electric field of magnitude 2.5 x 10^5 N/C. How much work is required to rotate the dipoles from this orientation (θ = 0°) to one in which all the moments are perpendicular to the field (θ = 90°)?