An electric current of I ampere is flowing in a long conductor CG as shown in figure. Find the magnitude and direction of magnetic induction at the centre O of circular part.

Answer

`(mu_0I)/(2r)(1/pi+1)` acting `_|_r` to loop upwards

Explanation

`vecB_0=vecB_(CG)+vecB_(DEF)`
`=(mu_0)/(4pi)(2I)/(r)hatn+(mu_0)/(4pi)(2piI)/(r)hatn=(mu_0I)/(2r)[1/pi+1]hatn`
where `hatn` is a unit vector perpendicular to loop upwards.