Question

An electric dipole is placed at the origin `O` and is directed along the `x`-axis. At a point `P`, far away from the dipole, the electric field is parallel to `y`-axis. `OP` makes an angle `theta` with the `x`-axis then
A. `tantheta sqrt(3)`
B. `tantheta=sqrt(2)`
C. `theta=45^(@)`
D. `tantheta=(1)/(sqrt(2))`

Answer 1

Correct Answer - B

`delta=theta_+phi rArr delta=theta+tan^(-1)((1)/(2)tantheta)`
given `delta=pi//2 rArr tan^(-1)((1)/(2)tantheta)=(pi)/(2)-theta`
`(1)/(2)tan theta=cot theta rArr tan theta=sqrt(2)`