If a copper wire carries a direct current, the magnetic field associated with the current would be:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Both inside and outside of the wire
$B_{inside}=\frac{μ_0Ir}{2πR^2},B_{outside}=\frac{μ_0I}{2πr}$
Therefore, a magnetic field exists both inside and outside of the wire.