**The Properties of Matter**- P.1.4 Employ correct units in describing common physical quantities.

**The Nature of Energy**- P.1.14 Explain the relation between energy (E) and power (P). Explain the definition of the unit of power, the watt.

**The Nature of Electricity & Magnetism**- P.1.18 Explain the concepts of ... electric current, electric potential, electric field ... Use the definitions of .... the ampere, the volt...
- P.1.19 Analyze simple arrangements of electrical components in series and parallel circuits. Know that any resistive element in a DC circuit dissipates energy, which heats the resistor. Calculate the power (rate of energy dissipation) using the formula Power = IV = I
^{2}R.

potential difference |
electric current |
Ampere |

voltage source |
electromotive force (emf) |
resistance |

Ohm |
Ohm's Law |
direct current |

alternating current |
transformer |
diode |

drift velocity (speed) |
electric power |

Objectives:

When you finish your study of electric current you should be able to:

- Tell what electric current is, and the units in which it is commonly measured. (34.2)
- Describe the conditions necessary for current to flow. (34.1)
- Given a diagram of a bulb, wire, and a battery, tell whether the bulb will be lit. (34.1)
- Name some common voltage sources. (34.3)
- Recognize electromotive force as a synonym for voltage. (34.3)
- Tell what resistance is and what units are used to measure it, and describe the factors that affect resistance. (34.4)
- Describe the relationship between current, resistance and voltage in a simple circuit. (34.5)
- State Ohm's Law and tell what each of the symbols mean. (34.5)
- Solve simple numerical problems involving: (34.5)
- Voltage (potential difference)
- Current
- Resistance

- Describe how an electric shock affects the human body. (34.6)
- Discuss ways to avoid electric shock. (34.6)
- Discuss emergency procedures in case of electric shock.
- Describe the difference between DC and AC voltage and current. (34.7)
- Tell whether household current is AC or DC and know the nominal voltage and frequency. (34.7)
- Tell what a diode does in an electric circuit. (34.8)
- Describe how AC can be converted to DC. (34.8)
- Describe the motion of electrons in a DC or an AC circuit, and discuss how energy is transported in a DC or an AC circuit. (34.9)
- Tell where the electrons in an electric circuit originate.(34.10)
- Recognize that electric power equals current times voltage. (34.11)
- Solve simple numerical problems involving: (34.11)
- Power
- Current
- Voltage
- Resistance

- Determine the cost to run an appliance given: (34.11)
- Power consumption of the appliance
- Time
- Energy cost per kilowatt hour

- Recognize the watt second and kilowatt hour as units of energy. (34.11)

Common Misconceptions to Correct:

In the study of electric current, it is very common for beginning physicists to have the following misconceptions - do you? If so, you need to put in some extra effort to discover why they are incorrect, and correct them!

**WRONG!**Electrons in an electric current move at nearly the speed of light.**WRONG!**The electrons in an electric circuit are supplied by the battery, generator, or wall outlet.**WRONG!**The energy in an electric current is carried by the electrons.

last update April 3, 2008 by JL Stanbrough