Electric Potential Energy and Work

Flashcards covering concepts related to electric potential energy, work, and equipotential surfaces.

Electric Force on Proton vs. Electron

In a constant electric field, a proton and an electron experience the same magnitude of electric force, but in opposite directions due to their opposite charges.

Acceleration of Proton vs. Electron

In a constant electric field, an electron has a larger acceleration than a proton because the electron is much less massive.

Kinetic Energy of Proton vs. Electron

In a constant electric field, a proton and an electron acquire the same kinetic energy when striking the opposite plate because they have the same initial electric potential energy and energy is conserved.

Work and Potential Energy

The work needed to assemble a collection of charges is the same as the total potential energy (PE) of those charges. PE is added over all pairs.

Electric Potential

The total potential is equal to V1 + V2, the total potential is positive.

Electric Potential at Equidistant Points

If two equal and opposite charges are equidistant from a point, the total electric potential at that point is zero.

Electric Field (E) and Potential (V) at the Center of a Square

With +Q and -Q charges at the corners, the electric potential (V) is zero because scalar contributions cancel, but the electric field (E) is non-zero because vector contributions add up.

Equipotential Surfaces

Points equidistant from equal and opposite charges have a potential of V=0. The electric field is not zero at these points.

V = 0 on the x-axis

V = 0 when opposite charges lie directly across the x axis from each other, the potentials from the two charges above the x axis cancel the ones below the x axis.

V = 0 on the y-axis

V = 0 when opposite charges lie directly across the y axis from each other, the potentials from the two charges above the y axis cancel the ones below the y axis.

Points with the Same Potential

Points that are at the same distance from a charge Q are at the same potential and lie on an equipotential surface.

Work and Electric Potential

Moving a positive charge against the electric field requires the most work. Easiest when the field does all the work. Moving along an equipotential requires no work.