Download Unit #6 Electric Charges, Forces, Current, and Circuits Learning

Unit #6 Electric Charges, Forces, Current, Circuits--Objectives text: ch 16 sec 1-5, 7; ch 17 sec 1, 7; ch 18 sec 1-6; ch 19 sec 2
1) identify static electricity; realize matter is electrically neutral, consisting of equal amounts + & - charges;
realize like charges repel, unlike charges attract; describe preparations, use of electroscope to demonstrate this
2) realize charge separation can occur--describe intentional / natural means of achieving; describe related examples:
charging by rubbing, contact, induction; lightning, static cling, Van de Graf generator, photocopying, zapping chips
3) state law of conservation of electric charge; realize charge e on electron is fundamental unit, other amounts can be
expressed as integral multiples of e; relate to the coulomb; distinguish conductors & insulators, ionic & molecular
4) identify electrostatics; identify Coulomb's Law--realize it applies to charges at rest; relate Coulomb's law to, contrast
with Law of Universal Gravitation; compare strength of gravity & electrical forces; work simple problems
5) describe electric field concept, relate to gravitational field, define using force on test charge; work simple problems
6) from gravitational potential energy considerations, describe electric potential energy, define electric potential V,
describe electric potential difference, relate to gravitational case (uniform field); identify volt; work simple problems
7) identify and characterize capacitors in general, describe charging a capacitor; relate charge Q on capacitor to potential
difference V; identify capacitance C, identify farad; work related problems
8) describe parallel plate capacitor, relate Q, C, & V to area A of plates & separation d, note how C can be increased;
9) discuss electricity (and flow of charge) by relating it to the flow of water and by making an analogy between the two,
likening flow of water in pipes to charges moving in wires, etc.
10) describe voltage V, connect with force pushing charges; identify unit (volt); realize as water flows due to a
difference in pressure, a potential difference is needed for charges to flow; describe what battery or source of
electromotive force (emf) does: appreciate battery chemical to electrical energy conversion
11) describe current I, connect with rate of flow of charge, identify unit (ampere) and work related problems; realize
negative current in one direction is equivalent to positive current in opposite direction & current direction refers to
positive charges moving in that direction
12) describe resistance R, connect with “what slows the flow, identify unit (ohm)
13) realize that current, voltage, and resistance are connected through Ohm’s Law; appreciate experimental basis of this
law; identify limitations in extending the water flow / electricity analogy
14) identify four things that determine resistance; identify resistivity, temperature coefficient of resistance; realize
resistance is present in resistors, load resistances, wires (but there can sometimes be neglected) and in other circuit
components; describe resistor construction
15) identify voltage drop, use the V=IR form of Ohm’s Law to calculate it; work related problems
16) use I = V/R form of Ohm’s Law to calculate current drawn when load resistance R exists across voltage V; for fixed
voltage, use I = V / R in describing open circuits and short circuits
17) describe electric power dissipated P, connect with rate of loss of electrical potential energy, use that and derive
P=IV, identify units (watts = amps x volts); work related problems; describe what occurs as current flows through
resistor, appreciate P=I2R heating, appreciate current rating of wires, power rating of resistors; work related
problems; describe what happens when fuse blows or circuit breaker trips
18) Determine the equivalent resistance of resistors hooked in series or in parallel; work related problems