Thousands of Magnetic Marbles Are Thrown into a Vertically Oriented

Multiple Choice

Thousands of magnetic marbles are thrown into a vertically oriented wind tunnel. As they are thrown, no marbles are free from other marbles. Instead, they clump together in groups of varying numbers. The wind tunnel operator is able to control the upward force of the wind so as to make clumps of marbles hover. She records the various forces of wind required to maintain hovering clumps in units of ounces: 45, 30, 60, 75, 105, 35, 80, 55, 90, 20, 65. From this data, what might be the weight of a single magnetic marble? What is the force of the wind analogous to within Millikan's experiment?

A) 3 ounces; the force of the wind is analogous to the force of gravity within Millikan's experiment.
B) 3 ounces; the force of the wind is analogous to the strength of the electric field within Millikan's experiment.
C) 5 ounces; the force of the wind is analogous to the force of gravity within Millikan's experiment.
D) 5 ounces; the force of the wind is analogous to the strength of the electric field within Millikan's experiment.