Part III – Equipotential Surfaces and Work in the Electric Field Begin with a si
ID: 1877632 • Letter: P
Question
Part III – Equipotential Surfaces and Work in the Electric Field
Begin with a single point charge and use the voltage plotting tool to create an equipotential curve around the point charge. Use an orange electric field sensor to investigate the relationship between the direction of the electric field and the orientation of the equipotential curve. Are the two parallel or perpendicular, or do they have some other more complicated relationship? Does this relationship hold for more complicated arrangements of charge, dipoles, and quadrupoles?
Figure 4. Point Charge and the voltage plotting tool.
Recall the definition of work: work = Fcos()x. Work can, of course, be done not only by the force of gravity but also by electrical forces. The definition of work done by electrical forces is
Work = (q E) cos() Displacement
Given your observations, speculate on the work required to move a very small test charge along (parallel to) an equipotential line.
Explanation / Answer
moving the very small test charge parallel to equipotential line , the angle between the electric field and displacement vector will be 90 since equipotential surface is at right angle relative to direction of electric field.
hence = 90
so work done is given as
Work = (q E) cos()
Work = (q E) cos(90)
Work = 0 J since Cos90 = 0