To determine resistance per cm of a given wire by plotting a graph for potential difference Vs. current.

APPARATUS WE SUPPLIED 

1. Battery Eliminator (0-12V) 
2. Voltmeter 3V
3. Ammeter (0-1A)
4. A piece of wire of known length 
5. Rheostat (50ohm, 1.6A)
6. One way key  
7. DCC wire                                                                                                                      

   According to Ohm’s law, the electric current flowing through a conductor is directly proportional to the potential difference across its ends, provided the physical state (pressure, temperature, and dimensions) of the conductor remains unchanged.

   If I is the current flowing through the conductor and V is the potential difference across its end, then

   
   

   V = RI

   Where R is the constant of proportionality and is termed as the electrical resistance of the conductor. Resistance R depends on the dimensions and material of the conductor. The relationship between the resistance of a material and its length and area of the cross-section is given by the formula

   
   

   Where ρ is the specific resistance or resistivity and is a characteristic of the material of th