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 (Figure19.32).

(a) Sketch the equipotential lines surrounding the ray.

(b) Sketch the equipotential when the ray is near a ship with a conducting surface.

(c) How could this charge distribution be of use to the ray?

The curve joining all the points that are at same potential inside an electric field is known as equipotential line. Two equipotential lines can never intersect.

(a)

Consider the lesser electric rays electric field. The blue and red lines represent field and equipotential lines respectively. The field is shown below-.

(b)

A negative charge is induced, when the ray is in the vicinity of the ship-

(c)

Because of the large quantity of charge, a ray creates a large electric field. When any ray creature is near it, the ray produces an opposite charge on the creature. Thus, the charge from the ray jumps to it, especially with sea water being a good conductor. Thus, the prey is stunned or dead. So the ray can eat it.

Therefore, the equipotential lines surrounding the ray and when the ray is near a ship is plotted. The ability to transfer charge is beneficial in hunting its prey.