Question

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 q with the x-axis, then –

• A. Tanq = $\sqrt{3}$
• B. Tan q =$\sqrt{2}$
• C. q = 45⁰
• D. Tan q = (1/$\sqrt{2}$)

Answer 1

Answer: (B)

Tan q =$\sqrt{2}$

Answer 2

Direction of electric field from axis of dipole is given by = q + tan^–1 $\left( \frac { \tan \theta } { 2 } \right)$

Here given that E is along y-axis.

q + tan^–1$\left( \frac { \tan \theta } { 2 } \right) = \frac { \pi } { 2 }$

$\frac { \tan \theta } { 2 } = \cot \theta$

tanq = 2 cot q Ž tan²q = 2

\ tanq = $\sqrt { 2 }$