A system has two charges `q_(A)= +2.5xx10^(-7)C and q_(B)= -2.5xx10^(-7)C` located at point 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

Both the charges can be located in a coordinate frame of reference as shown in the given figure.

At A, amount of charge, `q_(A) = 2.5 × 10^(−7)C`
At B, amount of charge, `q_(B) = −2.5 × 10^(−7) C`
Total charge of the system,
`q = q_(A) + q_(B)`
`= 2.5 × 10^(7) C − 2.5 × 10^(−7) C = 0`
Distance between two charges at points A and B,
d = 15 + 15 = 30 cm = 0.3 m
Electric dipole moment of the system is given by,
`p = q_(A) × d = q_(B) × d`
`= 2.5 × 10^(−7) × 0.3`
`= 7.5 × 10^(−8) C` m along positive z-axis
Therefore, the electric dipole moment of the system is `7.5 × 10^(−8) C m` along positive z−axis.