AP EAPCET 08-Jul-2022 Shift 2 Paper

Wire length ab and cd does not produces any field at O as this point lies an axis of wires

Arc bc produces an inward ⊗ magnetic field given by
B1=

µ0I

2R1

×

θ

360∘

=

4π×10−7

2×2×10−2

×

1.2

π

×

30

360

=

10−7

10−2×10

=10−6T
=103×10−9T=1000‌nT
Arc ad produces an outward ⊙ magnetic field given by
B2=

µ0I

2R2

×

θ

360∘

=

4π×10−7× 1.2 π ×30

2×1×10−2×360

=

2×10−7

10−2×10

=2×10−6
=2×103×10−9T=2000‌nT
Net field at centre
=B2⊙−B1⊗=2000−1000
=1000‌nT=103×10−9T
=10−6T=1µT
(No option is matching)