A current of 2A is maintained in a long straight conductor placed in air. Calculate the magnitude of the magnetic field at a distance of 2 m from the conductor.

$2×10^{-7} T$

The correct answer is Option (4) → $2×10^{-7} T$

Using Ampere's Law,

$B=\frac{μ_0I}{2πR}$

$=\frac{(4π×10^{-7})×2}{2π×2}$

$=\frac{8π×10^{-7}}{4π}=2×10^{-7} T$