A wire carrying a large and constant current passes through the center of and perpendicular to a piece of cardboard. If Iron filings are sprinkled on the cardboard, they arrange along magnetic lines of force that a are random Ob. are similar to those of a bar magnet Oc.extend straight outwards from the wire O d. form concentric circles surrounding the wire 3. Answer: The correct match of the laboratory equipment that could be used to detect a gravitational, electric or magnetic field, respectively, is sequence, on the answer sheet.) 1. 2. 3. An electroscope A small test mass A compass Answer: S The correct definitions for defining the directions of gravitational, electric, and magnetic fields, respectively, are sheet.) Laboratory Equipment or Supplies Direction of the force on a small test mass Direction of the force on the N-pole of a small compass Direction of geographic north Direction of the force on a positive test charge M Bar Magnet Directions of Fields The direction of the magnetic field, at point X, is toward the: bottom of the page Ob right of the page OC left of the page Od. top of the page and and (Record all three digits of your answer, in correct (Record all three digits of your answer, in correct sequence, on the answer