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Explore the concepts of electrical forces, charges, conductors, insulators, semiconductors, superconductors, and more in this informative lecture series. Discover why electrical forces don't tear everything apart and how atoms and electrons interact. Learn about charging by friction, induction, and grounding, as well as electric shielding and electric potential. Get a deep understanding of these fundamental principles in physics.
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Electrical forces p373 Electrical forces are a gazillion times stronger than gravity. They should crush together or tear everything apart. BUT THEY DON’T. Because there are two (2) electrical forces that bunch together in atoms and are basically neutral. Thank you atoms!
Electrical Charges p373 1. Positive nucleus…negative electrons. 2. Electrons are all the same. 3. Nucleus: protons and neutrons…blah, blah. 4. Atoms are neutral until they become ions…….. Electrons don’t orbit in orbitals. They exist in an area. Think of electrons as waves that need a certain amount of space. The areas are called shells…which are divided into subshells…which are divided into orbitals…which are divided into spins. The whole periodic table is designed along these lines.
Actually, these lines: Shells Subshells s p d f spin Why don’t positive protons fly apart? Because there are even stronger forces at short range.
Conservation of Charge p374 The hair and the plastic start out neutral. Rubbing the electrons onto the plastic makes the plastic rod negative and the hair is now positive. + Charges aren’t created or destroyed, but they can be moved around. Please remember that it takes energy to add/remove electrons.
Conductors and Insulators p377 Conductors have a “sea” of electrons. When a positive charge is put on one side of the wire and a negative charge on the other, then, electrons migrate toward the positive side. Insulators have tightly bound electrons which don’t move. Actually, there’s a rainbow of conduction/insulation.
Semiconductors p378 They’re in the middle of the strong/weak electron bond thing. By adding impurities they can be made to conduct or to insulate. A whole bunch of these semiconducting thingies make a transistor. Superconductors p378 A material with infinite conductivity. 1987- a material that would superconduct over 100K was discovered.
Charging p379 Charging by friction Rubbing on/off electrons. Then by contact…
Charging by 3 and 4 3 Charging by Induction p379 4 Charging by Grounding p380
Friction of ice chunk vs ice chunk may be the method of charging the cloud. The negative bottom of the cloud drives electrons away on the ground below.
Electric Shielding p386 A and B push equally on the charged point. “A” is 4x the charge but 2x the distance. The NIFTY thing is that the E-field inside a conductor is always zero. 0 0 0
Electric Potential p388 Losing Electric PE Losing GPE:
More on Electric Potential Pushing creates energy in the spring. Likewise, pushing a charge closer to another like charge creates energy. The closer two like charges are then, the more electric potential energy they have. It is convenient to define the electric potential energy per charge as electric potential. Electric potential is volts. Electric potential energy volts = Electric potential = charge
Van de Graaff Generator p392 Scary, but safe. Large V…small # charges. The end