What is Ohm’s law

Georg Simon Ohm

• Ohm’s Law states that at a constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends.
• Law states that                                    I∝V (at constant temperature)
  this can also be written as                 V∝I   

                                           Or                           V=R×I

                                                                          R=V/I
                                                                           V=Potential differnce
                                                                        I=Current
                                                                        R=Resistance  (which is a constant)
ohm’s law is represented by a graph:-

Here question arises what is a Resistance. So,

What is Resistance

• Electrical Resistance is the quantity that determines how much difficulty current faces while flowing through a conductor.
• The Resistance of a conductor depends on the length, thickness, nature of material, and temperature of the conductor.
• It is the measure of voltage divided by current or voltage/current(V/I)
• It is represented by R.
• It’s SI unit is ‘0hm’ and with symbol Omega (Ω).
• 1 0hm=1 volt/1 ampere
  

let’s do a question on resistance:-
The potential difference between two points of a wire carrying a 2 amperes current is 0.1 volt. calculate the resistance between these points? 

solution:-
from ohm’s law we have:
Potential difference/Current=Resistance
or 
V/I=R
Here, Potential difference,V=0.1 Volt
            Current,I=2 Amperes
           Resistance,R=?
putting these values in the above formula, we get:
                        0.1/2=R
                        0.05=R
or               Resistance,R=0.05 ohm        or (0.05 Ω).