Answer to Question #66511 in Electric Circuits for Chelsea

Question

Maybe we’ll make a Dunk Tank for the Spring Spectacular this year.2 Pictured is
a schematic for a Dunk Tank. A rectangular loop of wire consisting of 200 coils is
immersed in a strong magnetic field of 1.85 T. The length of the horizontal section of
the loop that is within the field is 0.550 m, and the orientation is fixed so that the loop
may only move up or down (i.e., to provide the tension in the cable supporting Dr.
Miller). Current is supplied to the coil and the resulting force holds up Dr. Miller, who
has a mass of 75.5 kg including the light seat. What current is required to balance the
system? What direction does the current have to flow in the diagram?