1. Current, resistance, power

a) Students should understand the definition of electric current, so they can relate the magnitude and direction of the current to the rate of flow of positive and negative charge.

b) Students should understand conductivity, resistivity, and resistance, so they can:

1) Relate current and voltage for a resistor.

2) Write the relationship between electric field strength and current density in a conductor, and describe, in terms of the drift velocity of electrons, why such a relationship is plausible.

3) Describe how the resistance of a resistor depends upon its length and cross-sectional area, and apply this result in comparing current flow in resistors of the different material or different geometry.

4) Derive an expression for the resistance of a resistor of uniform cross-section in terms of its dimensions and the resistivity of the material from which it is constructed.

5) Derive expressions that relate the current, voltage and resistance to the rate at which heat is produced when current passes through a resistor.

6) Apply the relationships for the rate of heat production in a resistor.