OHM’S LAW



In 1927 George Simon Ohm found the relationship between current (I) flow through a conductor and the potential difference(v) across ends of that conductor. Law that defines this relationship is the OHM’S Law

DEFINITION OF OHM’S LAW

 The potential difference across ends of a conductor is directly proportional to the current flowing through it. Provided it’s temperature remains the same.

Ie        V α I

          (To change the proportionality to equal multiply with a constant)

            V= a constant x I

            ( constant is the resistance of a conductor (R))

Ie.       V= RI      OR   R=V/I     OR          I= V/R

GRAPHICAL REPRESENTATION OF OHM’S LAW

Connect a resistance wire(nichrome wire) in circuit with rheostat, ammeter and voltmeter. Change voltage and measure the current across the resistance. Then plot a graph with voltage along x-axis and current along y-axis. Graph obtained will be same as shown below 


OHM’S law graph shows that as voltage in a circuit increases the current flowing through the circuit also increases. Slop of this graph gives resistance.
ie,  V α I
      V= a constant × I
      V/I= a constant 
     ( That constant is the resistance)

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