Water molecules have a permanent dipole moment of about p = 6.3 × 10−30 C m. In the following user = 0.9584 × 10−10 m for the H-O distance and α = 104.45◦ for the H-O-H angle. 

a) One can imagine the total dipole of water as comprising of a charge +q on each hydrogen atom, and a charge −2q on the oxygen atom. Calculate the value of q in units of elementary charges given the values of p, r, and α above.

b) For one dipole aligned along the z-axis and centered at z = 0 The potential V of the dipole is zero at z = 0. Not in this case. Find the condition for V = 0 for the total potential from the water dipoles. Give the expression and the numerical value.