Question

Three parallel wires, each carrying a current I (left and right wire carry upward current and middle wire carries downward current....but all wires have the same magnitude current). Four points are identified on the picture as well.   What are the directions of the magnetic fields at the four points, starting with point 1, then 2, etc.

1

Question options:

	1: in, 2: in, 3: out, 4: out
	1: in, 2: out, 3: out, 4: in
	none of these
	1: out, 2: in, 3: out, 4: in
	1: out, 2: in, 3: in, 4: out

Question

A wire is wrapped around a cardboard tube and carries a steady current in the direction shown (up in front, down in back).   If an observer were inside the tube, near the center, which direction would the observer expect to experience the magnetic field?

Question options:

	pointing into the picture
	none of these
	pointing to the left
	pointing to the right
	pointing out of the picture

Question

Two concentric circular loops of wire each carry current I. The smaller loop has a clockwise current, while the larger loop carries a counterclockwise current. Point P is located at the center of both circles. What is the direction of the magnetic field at point P?

Question options:

	out of the picture
	there's no field, because the two contributions cancel
	straight upward
	into the picture
	straight downward

Question

How far apart must two parallel wires be if they both carry I = 24 A and have a force per unit length of interaction between them of 4.4 x 10^-3 N/m?

Question options:

	2.6 cm
	3.9 cm
	1.3 cm
	26 cm
	13 cm

Answer 1