1. . An electric dipole located at the origin in free space has a moment p = 3ax −2ay +az nC·m. Find V at r = 2.5, θ =30◦, φ =40◦. I find it difficult to solve when its in spherical co-ordinates. 2.Relevent Eq V =P.(r-r')/( 4∏ε|r−r'|2)(|r-r'|) I am confused how to find a unit vector on spherical co-ordinate. ie |r-r'| This que is from william Hayt and page no 100.