Question -
Answer -
Both the charges can be locatedin a coordinate frame of reference as shown in the given figure.
At A, amount of charge,┬аqA┬а=2.5 ├Ч 10тИТ7C
At B, amount of charge,┬аqB┬а=тИТ2.5 ├Ч 10тИТ7┬аC
Total charge of the system,
q┬а=┬аqA┬а+┬аqB
= 2.5 ├Ч 10тИТ7┬аC тИТ2.5 ├Ч 10тИТ7┬аC
= 0
Distance between two charges atpoints A and B,
d┬а=15 + 15 = 30 cm = 0.3 m
Electric dipole moment of thesystem is given by,
p┬а=┬аqA┬а├Ч┬аd=┬аqB┬а├Ч┬аd
= 2.5 ├Ч 10тИТ7┬а├Ч0.3
= 7.5 ├Ч 10тИТ8┬аC malong positive┬аz-axis
Therefore, the electric dipolemoment of the system is 7.5 ├Ч 10тИТ8┬аC m along positive┬аzтИТaxis.