# Terms & Objectives     ## The Indiana Physics Standards that Relate to Chapter 34 - Electric Current are:

• 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 = I2R.

## New Terms:

 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:

1. Tell what electric current is, and the units in which it is commonly measured. (34.2)
2. Describe the conditions necessary for current to flow. (34.1)
3. Given a diagram of a bulb, wire, and a battery, tell whether the bulb will be lit. (34.1)
4. Name some common voltage sources. (34.3)
5. Recognize electromotive force as a synonym for voltage. (34.3)
6. Tell what resistance is and what units are used to measure it, and describe the factors that affect resistance. (34.4)
7. Describe the relationship between current, resistance and voltage in a simple circuit. (34.5)
8. State Ohm's Law and tell what each of the symbols mean. (34.5)
9. Solve simple numerical problems involving: (34.5)
1. Voltage (potential difference)
2. Current
3. Resistance
10. Describe how an electric shock affects the human body. (34.6)
11. Discuss ways to avoid electric shock. (34.6)
12. Discuss emergency procedures in case of electric shock.
13. Describe the difference between DC and AC voltage and current. (34.7)
14. Tell whether household current is AC or DC and know the nominal voltage and frequency. (34.7)
15. Tell what a diode does in an electric circuit. (34.8)
16. Describe how AC can be converted to DC. (34.8)
17. 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)
18. Tell where the electrons in an electric circuit originate.(34.10)
19. Recognize that electric power equals current times voltage. (34.11)
20. Solve simple numerical problems involving: (34.11)
1. Power
2. Current
3. Voltage
4. Resistance
21. Determine the cost to run an appliance given: (34.11)
1. Power consumption of the appliance
2. Time
3. Energy cost per kilowatt hour
22. 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