question_answer

A current \[i\] is flowing in a straight conductor of length L. The magnetic induction at a point on its axis at a distance \[\frac{\operatorname{L}}{4}\]  from its centre will be:     JEE Main  Online Paper (Held On 22 April 2013)

A)  Zero                      

B)  \[\frac{{{\mu }_{0}}\operatorname{i}}{2\pi L}\]

C)  \[\frac{{{\mu }_{0}}\operatorname{i}}{\sqrt{2L}}\]                      

D)  \[\frac{4{{\mu }_{0}}\operatorname{i}}{\sqrt{5}\,\pi L}\]