To determine the resistance per cm of a given wire by plotting a graph of potential difference versus current.
What does Ohm's Law state?
According to the Ohm's law, "The current flowing through a conductor is directly proportional to the potential difference across its ends provided the physical conditions (temperature, dimensions, pressure) of the conductor remains the same." If I be the current flowing through a conductor and V be the potential difference across its ends, then according to Ohm's Law,
where, R is the constant of proportionality. It is known as resistance of the conductor. Or
..the working formula
R depends upon the material, temperature and dimensions of the conductor.
In S.I. units, the potential difference V is measured in volt and the current I in ampere, the resistance R is measured in ohm.
How do we establish the current-voltage relationship?
To establish the current-voltage relationship, it is to be shown that the ratio V / I remains constant for a given resistance, therefore a graph between the potential difference(V) and the current (I) must be a straight line.
How then do we find the unknown values of resistance?
It is the constant ratio that gives the unknown values of resistance,
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