A wire carrying current I has the shape as shown in adjoining figure. Linear parts of the wire are very long and parallel to X-axis while semicircular portion of radius R is lying in Y-Z plane. Magnetic field at point O is :
As discussed in
For Infinite Length -
- wherein
Parallel wires 1 and 3 are semi infinite, so magnetic field at 0 due to them
Magnetic field at 0 due to semicircular arc in yz plane is given by
Option 1)
Option 2)
Option 3)
Option 4)