A compass needle placed 4.0cm east of a long straight conductor experiences a magnetic field of 6.4×10−5T. Assume the conductor is infinitely long and carries a steady current. Take μ0=4π×10−7TmA−1.
a. (i) Calculate the current in the conductor.
b. (ii) Keeping the current unchanged, determine the magnetic field when the compass is moved to a point 2.0cm from the conductor.