Class-12th Physics, CBSE and UP Board
Electric Charges and Fields,
Chapter-1, Exercise -1, Q-1.9
NCERT Solutions for Class 12th Physics
A system has two charges q₁ = 2.5 × 10⁻⁷C and q₂ = –2.5 × 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?
Share
Imagine both the charges located in a coordinate frame of reference.
At A, amount of charge, qA = 2.5 x 10_7C
At B, amount of charge, qB = —2.5 x 10-7 C
Total charge of the system, q = qA + qB = 2.5 x 10_7 C – 2.5 x 10-7C = 0
Distance between two charges at points A and B, d= 15 + 15 = 30 cm = 0.3 m
Then Electric dipole moment of the system is given by,
p = qAx d = qBx d = 2.5 x 10_7 x 0.3 = 7.5 x 10~8 C m along positive z-axis
Therefore, the electric dipole moment of the system is 7.5 x 10~8 C m along positive z-axis.