Chapter Summary

Ohm's Law states that the amount of current through a conductor, at constant
temperature, is proportional to the voltage across the resistor. Mathematically we
write I=VR

Conductors that obey Ohm's Law are called ohmic conductors; those that do not are
called non-ohmic conductors.

We use Ohm's Law to calculate the resistance of a resistor. R=VI

The equivalent resistance of resistors in series (Rs) can be calculated as
follows: Rs=R1+R2+R3+…+Rn

The equivalent resistance of resistors in parallel (Rp) can be calculated as
follows:1Rp=1R1+1R2+1R3+…+1Rn

Electrical power is the rate at which electrical energy is converted in an electric circuit.

The electrical power dissipated in a circuit element or device is P=VI and can also be
written as P=I2R or P=V2R and is measured in joules (J).

The electrical energy dissipated is E=Pt and is measured in joules (J).

One kilowatt hour refers to the use of one kilowatt of power for one hour.
Physical Quantities
Quantity
Unit name
Unit symbol
Current (I)
Amperes
A
Electrical energy (E)
Joules
J
Power (P)
Watts
W
Resistance (R)
Ohms
Ω
Voltage (V)
Volts
V
Table 1: Units used in electrostatics