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?
The charge distribution in lesser electric ray acts as a defense mechanism against its enemies. Since there is equal and opposite charge buildup at its two ends, any object that comes in contact with it will complete the circuit and will receive an electric shock which is the discharge of the built up charge.