|Energy Work Power|
|Properties Of Matter|
|Heat Temperature And Thermal Expansion|
|--Electric Current and flow of Charge|
|--Ohm's Law Resistance and Resistors|
|--Combination of Resistors|
|--Common Electric Circuits and Combination of Batteries|
|--Alternating Current and Direct Current and Diodes|
|--Electric Power and Energy|
|--Finding Potential Difference Between Two Points in Circuits with Examples|
|--Electric Current Cheatsheet|
|Exams and Problem Solutions|
Ohm’s Law Resistance and Resistors
Resistance is the difficulty applied by the conductor to the current flowing through it. Each material has different resistance. We show resistance with R and unit of it is ohm (Ω).
1 Ω=resistance of the conductor when 1 A current flows under the 1 V potential difference. Resistance is represented with the following picture in circuits;
Rheostat is a kind of device used to vary existing resistance. It is shown in the circuits as;
Resistance of the conductor depends on;
· Types of the material or electrical resistivity of the material. It is shown with Greek letter ρ. Resistance of the material is linearly proportional to electrical resistivity.
· Length of the material (l). Resistance is linearly proportional to the length of the conductor.
· Cross sectional are of the conductor. Resistance is inversely proportional to the cross sectional area.
· Temperature. Temperature shows different effects with respect to the type of material.
We write resistance formula with the explanation given above as;
Ohm’s law gives the relation between voltage, current and resistance. According to Ohm, current in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the conductor. We can summarize this explanation with following formula;
If we take resistance of the conductor constant, then potential difference and current of the system changes linearly as shown in the following graph;
Example: Potential difference vs. Current graph of a conductor is given below, Find the behavior of resistance in intervals I, II and III.
Ohm’s law states that V=I.R