A short electric dipole is fixed at the origin. A point charge q placed at a large distance r on the axial line of the dipole experiences an electrostatic force of magnitude F . If the same point charge is then moved to a distance 2r on the equatorial plane of the dipole, the magnitude of the new electrostatic force experienced by the charge will be :

Step-by-step solution

The electric field on the axial line of a short dipole at a distance r is: E_ axial = 2kp r^3 The force on the point charge q is: F = qE_ axial = 2kpq r^3 The electric field on the equatorial plane of the dipole at a distance 2r is: E_ equatorial = kp (2r)^3 = kp 8r^3 The new force on the point charge q is: F' = qE_ equatorial = kpq 8r^3 Taking the ratio of F' to F : F' F = kpq 8r^3 2kpq r^3 = 1 16 Thus, F' = F 16 . Answer: F 16