3. If the earth's magnetism is assumed to originate from a large circular loop of current within the earth, then the plane of the current loop must be oriented, to the earth's magnetic axis, and the direction of the current around the loop (when looking down on the loop from the north magnetic pole) is. a. parallel, clockwise b. parallel, counterclockwise c. perpendicular, clockwise d. perpendicular, counterclockwise 4. Suppose that you have two bars. Bar 1 is a permanent magnet and bar 2 is not a magnet, but is made from a ferromagnetic material like iron. A third bar (bar 3), which is known to be a permanent magnet, is brought close to one end of bar 1 and then to one end of bar 2. Which one of the following statements is true? a. Bars 1 and 3 will either be attracted to or repelled from each other, while bars 2 and 3 will always be repelled from each other. b. Bars 1 and 3 will either be attracted to or repelled from each other, while bars 2 and 3 will always be attracted to each other. c. Bars 1 and 3 will always be repelled from each other, while bars 2 and 3 will either be attracted to or repelled from each other. d. Bars 1 and 3 will always be attracted to each other, while bars 2 and 3 will either be attracted to or repelled from each other. 5. At a location near the equator, the earth's magnetic field is horizontal and points north. An electron is moving vertically upward from the ground. What is the direction of the magnetic force that acts on the electron? a. North b. East c. South d. West

3. If the earth's magnetism is assumed to originate from a large circular loop of current within the earth, then the plane of the current loop must be oriented, to the earth's magnetic axis, and the direction of the current around the loop (when looking down on the loop from the north magnetic pole) is. a. parallel, clockwise b. parallel, counterclockwise c. perpendicular, clockwise d. perpendicular, counterclockwise 4. Suppose that you have two bars. Bar 1 is a permanent magnet and bar 2 is not a magnet, but is made from a ferromagnetic material like iron. A third bar (bar 3), which is known to be a permanent magnet, is brought close to one end of bar 1 and then to one end of bar 2. Which one of the following statements is true? a. Bars 1 and 3 will either be attracted to or repelled from each other, while bars 2 and 3 will always be repelled from each other. b. Bars 1 and 3 will either be attracted to or repelled from each other, while bars 2 and 3 will always be attracted to each other. c. Bars 1 and 3 will always be repelled from each other, while bars 2 and 3 will either be attracted to or repelled from each other. d. Bars 1 and 3 will always be attracted to each other, while bars 2 and 3 will either be attracted to or repelled from each other. 5. At a location near the equator, the earth's magnetic field is horizontal and points north. An electron is moving vertically upward from the ground. What is the direction of the magnetic force that acts on the electron? a. North b. East c. South d. West