A long straight conductor is placed 5.0 cm east of a compass needle. The horizontal component of the Earth’s magnetic field at the location is 3.0×10−5T directed toward geographic north. What current through the conductor, directed vertically upward, will produce a magnetic field of the same magnitude at the compass position?
a) 15A
b) 7.5A
c) 3.0A
d) 1.5A