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Chapter 20

20.1 Current

20.2 Ohm’s Law: Resistance and Simple Circuits

20.3 Resistance and Resistivity

20.4 Electric Power and Energy

20.5 Alternating Current versus Direct Current

20.6 Electric Hazards and the Human Body

20.7 Nerve Conduction–Electrocardiograms

Chapter 21

21.1 Resistors in Series and Parallel

21.2 Electromotive Force: Terminal Voltage

21.3 Kirchhoff’s Rules

21.4 DC Voltmeters and Ammeters

Main Ideas

Electric current [latex]I[/latex]

[latex]I=\Delta{Q}/\Delta{t}[/latex],

[latex]\Delta{Q}[/latex] is the amount of charge passing through a given area in time [latex]\Delta{t}[/latex].

Ohm’s law

[latex]I=V/R[/latex],

[latex]I[/latex] is electric current, [latex]V[/latex] is voltage, [latex]R[/latex] is resistance.

Electric power [latex]P[/latex]

[latex]P=IV[/latex]

Electromotive force

Electromotive force (emf) is NOT a force at all. It is a type of potential difference.

SI unit  of emf is V (volt).

Emf is the potential difference of a source when no current is flowing.

Additional Resources

Eclectic current