question_answer

A line of charge with linear charge density X extends along the z-axis from \[z=-h\] to \[z=+h\]. The distance of the point on the y-axis where electric field has magnitude \[\frac{\lambda }{\sqrt{8}\pi {{\in }_{0}}h},\]is                                          

A)  h from the wire              

B)  \[\sqrt{2}\]h from the wire

C)  2h from the wire

D)  3h from the wire.

Correct Answer: A

Solution :

\[E=\frac{\lambda }{2\pi {{\varepsilon }_{0}}y}\sin \theta =\frac{\lambda }{2\sqrt{2}\pi {{\varepsilon }_{0}}h}\therefore y=h\]