Current and Resistance Chapter 26 Current and Resistance In this chapter we will introduce the following new concepts: -Electric current ( symbol i ) -Electric current density vector (symbol ) -Drift speed (symbol vd ) -Resistance (symbol R ) and resistivity (symbol ρ ) of a conductor -Ohmic and non-Ohmic conductors We will also cover the following topics: -Ohm’s law -Power in electric circuits (26-1)

A B (26-2)

i + q conductor i - q conductor (26-3)

i + q conductor A i - q conductor A (26-4)

(26-5)

+ - i V R (26-6)

+ - i V (26-7)

(26-8)

(26-9)

(26-11)

(26-12)

V (26-13)