In the figure, what is the magnetic field at the point `O`?

Options

A. `(mu_(0)I)/(4pir)`
B. `(mu_(0)I)/(4pir)+(mu_(0)I)/(2pir)`
C. `(mu_(0)I)/(4r)+(mu_(0)I)/(4pir)`
D. `(mu_(0)I)/(4r)-(mu_(0)I)/(4pir)`

Answer

C

Explanation

Magnetic field due to different parts are
`B_(1)=0`
`B_(2)=(mu_(0))/(4pi).(pii)/r o.`
`B_(3)=(mu_(0))/(4pi).(i)/r o.`
`:. B_("net")=B_(2)+B_(3)=(mu_(0)i)/(4r)+(mu_(0)i)/(4pir)`