question_answer

Directions Q. Nos. 12 are based on the following paragraph. A current loop ABCD is held fixed on the plane of the paper as shown in the figure. The arcs BC (radius =b) and DA (radius = a) of the loop are joined by the straight wires AB and CD. A steady current  is flowing in the loop. Angle made by A B and CD at the origin O is 30°. Another straight thin wire with steady current  flowing out of the plane of the paper is kept at the origin.   The magnitude of the magnetic field (B) due to the loop ABCD at the origin (O) is   AIEEE  Solved  Paper-2009  

A) zero

B) \[\frac{{{\mu }_{0}}I(b-a)}{24ab}\]

C) \[\frac{{{\mu }_{0}}I}{4\pi }\left[ \frac{b-a}{ab} \right]\]

D) \[\frac{{{\mu }_{0}}I}{4\pi }\left[ 2(b\_a)+\frac{\pi }{3}(a+b) \right]\]