Edited Invalid date
20.2 Ohm's Law: Resistance and Simple Circuits
The equation can be used to calculate the drift velocity.
The charge of an electron is given.
The formula can be used to calculate the area of a cross-section of the wire.
The periodic table shows that the atomic mass of copper is 63.54 g/mol.
We can use the two quantities and Avogadro's number to determine the number of free electrons.
The density of free electrons in copper is calculated first.
There is one electron for every copper atom.
The number of copper atoms is the same.
The negative charges are moving in a different direction than conventional current.
We can think of batteries, generators, wall outlets, and so on, which are necessary to maintain a current.
The devices create a potential difference and are referred to as voltage sources.
An electric field is created when a voltage source is connected to a conductor.
The electric field exerts force on charges.
The voltage applied to a substance affects the current that flows through it.
It can be seen as a cause-and-effect relationship.
This is an empirical law that has been observed.
Sometimes a linear relationship doesn't happen.
The substance has moving charges and atoms that transfer energy to the substance.
If resistance doubles, current is cut in half.
The relationship is called Ohm's law.
This form of Ohm's law defines resistance for certain materials.
Hooke's law is not universally valid.
Good conductors like copper and aluminum are included.
Ohmic materials have a resistance that is not dependent on current or voltage.
Even if the object's resistance is small, it's still called a Resistor.
The schematic is shown in Figure 20.8 The wires connecting the source of the power to the resistance can be assumed to not have resistance at all.
A simple electric circuit in which a closed path for current to flow is supplied by conductors is represented by the red parallel lines.
Any resistance in the connections to the voltage source is represented by the zigzag symbol.
We can use Ohm's law to find resistance.
The small resistance is larger than the cold resistance of the headlight.
The bulb has a lower resistance when it is first switched on because it draws more current during its brief warm-up period.
Resistances range in size.
Review flashcards and saved quizzes
Getting your flashcards
Privacy & Terms