Lesson 31 Voltage Energy and Force

Voltage (electric potential) is a measure of the electric charge. The following observation unveils the dilemma between electric force and potential. Electrons in a body are held together by only 3-5v, and batteries cannot shoot electric beams like the Van de Graaff generator.

The electric field is the negative derivative of potential.

v = -integral (E dr)

E = K(e) (q/r^2) r^

V = -K(e) integral (q/r^2 dr)

V = K(e) q/r

The integral of the electric field of a point charge is proportional to 1/r.

It requires no work to move a charge along a curve of constant potential.

The electric field is perpendicular to each equal potential at every point. Electric potential is the ability to do work by making electric charges flow, this potential is measured in volts.

The electric chair was one of the first uses of high voltage (neon lights)

Atoms, the basis of all matter is held together by electricity.

In every atom, the electric force binds negatively charged electrons to a positive nucleus. The nucleus can be considered a point charge even though it is comprised of protons and neutrons. One electron has exactly the amount of negative charge to balance with the positive charge, and result in a perfectly neutral atom.

The distance between the nucleus and the outermost electron is 1 Angstrom = 10^-8 cm.

All other electrons balance with all protons except one, and the remaining electron detects the electric field of the proton only 1 A(o) away.

The electric potential = 14.4 V

U = qV

because charge is negative, so is potential energy at 14.4eV, this must be overcome to remove an electron from an atom:

If an atom and a 100,000 V vandegraph fight over an electron the atom will win. This is not
because of voltage, but force. The derivative of potential energy.

The force of the atom is 100,000 times stronger than that of the Van de Graaff.

In lightning, the molecules of air are momentarily ionized leaving a gas of positive molecular ions and negative electrons called a plasma. The electric force between ions and electrons causes them to recombine into neutral matter giving off excess energy in the form of light.

In a neon light, the process is slowed to a continuous glow, but the electric field in a neon light cannot ionize matter.

The neon light and Van de Graaff generator ionize air through collisions that contains not electric force, but a few accidental electrons that hit other molecules. If the electric field is great enough, thus increasing acceleration and the distance between atoms is large enough, the electron can build enough energy to knock another electron off an atom. This causes a chain reaction due to higher acceleration and a spark.

The force of electricity depends on both voltage and charge. Voltage, energy, and force hold the universe together.