__Ohm’s Law__

__Ohm’s Law__

**In 1827 a German physicist Georg Simon Ohm found out the relationship between the current and potential difference which is known as Ohm’s Law.**

__Ohm’s Law__

__Ohm’s Law__

**The potential difference (V) across the end of a given metalic wire in an electric circuit is directly porpotional to the current flowing through it provided its temperature remains the same. this is called Ohm’s Law.**

**potential difference ∝ electric current V ∝ I**

**The resistance of a conductor isthe ratio of the flowing current. Its S.I. unit is Ohm. Represented by the Greek letter Ω **

** if V ∝ I**

** Potential difference = Resistance X Current**

**Resistance = potential difference / Current**

**Define 1 Ohm.**

**If the potential difference across the two ends of a conductor is volt and current through it is 1 A. Then the resistance R , of the conductor is 1 Ohm**

**1 Ohm = 1 volt / 1 ampere**

**The current through a resistor is inversely porpotional to its resistance.**

**What is variable resistance?**

**A component used to regulate current without changing the voltage source is called variable resistance.**

**Which device is used to change resistance in the circuit?**

**A device called rheostat is often used to change the resistance in the circuit.**

**The electron are not completely free to move within a conductor. They are restrained by the attraction of the atoms among which they move.**

**Motion of electron through a conductor is resistance is a good conductor.**

**A componnt of a given size that offer a low resistance is a good conductor.**

**A conductor having some appereiable resistance is called a resistor.**

**A component of identical e tat offer a higher resistance is a poor conductor.**