Chapter 19, Problem 45PE

The lesser electric ray (Narcine bancroftii) maintains an incredible charge on its head and a charge equal in magnitude but opposite in sign on its tail (Figure 19.32). (a) Sketch the equipotential lines surrounding the ray. (b) Sketch the equipotentials when the ray is near a ship with a conducting surface. (C) How could this charge distribution be of use to the ray?

Figure 19.32 Lesser electric ray (Narcine bancroftii) (credit: National Oceanic and Atmospheric Administration, NOAAs Fisheries Collection).