An electric dipole is placed at the origin and is directed along the x-axis. At a point P, far away from the dipole, the electric field is parallel to the y-axis. OP makes an angle θ with the x-axis.
(a) tan θ = √3
(b) tan θ = √2
(c) θ = 45°
(d) tan θ = 1/√2
Correct Answer is: (b) tan θ = √2
EP = k 2p/r3 √(3cos2 θ + 1).
VP = k 2p/r2 cos θ.
For A, θ = 0, for B, θ = 90°, r = OA = OB, tan ϕ = 1/2 tan θ.
θ + ϕ = 90°
or tan(90 - θ) = 1/2 tan θ
or 2cot θ = tan θ
or tan θ = √2.
