A system has two charges `qA = 2.5 xx 10^(–7) C and qB = –2.5 xx 10^(–7)C` located at points A: (0, 0, –15 cm) and B: (0,0, +15 cm), respectively. What are the total charge and electric dipole moment of the system?

Explanation

The two charges `q_(A)` and `q_(B)` are equal and opposite and situated a fixed distance apart, from an electric dipole. Thus the charge of the system is
`q_(A)+q_(B)=2.5xx10^(-7)C - 2.5xx10^(-7)C=0`
The distance between the two charges is `2a=30cm=0.3m`. So the dipole moment of the system is either charge`xx2a`
`=(2.5xx10^(-7)C)(0.3cm)=7.5xx10^(-8)Cm`
The direction of `vec(p)` as shown in fig. is from B to A, i.e. along the negative z-axis.