In a circular loop of wire lying on a horizontal floor, the current is constant and, to a person looking downward, has a clockwise direction. The accompanying magnetic field at the center of the circle is directed a) horizontally and to the east. d) parallel to the floor. b) horizontally and to the north. e) vertically downward. c) vertically upward.

e) vertically downward.

Explanation:

Direction of magnetic field due to a current carrying circular coil is known from the screw rule or right hand thumb rule.

Screw rule states that if we turn the screw driver in the direction of current in the coil , the direction of movement of rod of screw driver gives the direction of magnetic field.  if we turn the screw driver clockwise , it will move forward . That means magnetic field will be towards vertically downward direction .

Thumb Rule states that if we hold our closed fist such that the folded four fingers are in the direction of circular current , our thumb will show the direction of magnetic field. This also shows that magnetic field will be vertically downwards.

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it