A system has two charges qA = 2.5 10 power -7 C and qB = 2.5 10 power -7C located at points A: 0,0, -15cm and B: 0,0, +15cm, respectively. What are the total charge and electric dipole moment of the system? | question and answer !

Question :-

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

Answer :-

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

At A, amount of charge, qA = 2.5 10 power -7 C

At B, amount of charge, qB = 2.5 10 power -7 C

Total charge of the system,

q = qa + qb

2.5 x 10 power 7 C - 2.5 x 10 power -7 C    



=0

Distance between two charges at points A and B,

d = 15 + 15 = 30cm = 0.3m

Electric dipole moment of the system is given by,

p = qa x d = qb x d

= 2.5 x 10 power -7 x 0.3

= 7.5 x 10 power -8 Cm along negative z-axis

Therefore,

The electric dipole moment of the system is 7.5 x 10 power -8 Cm, along negative Z- axis.