‘The ratio of potential difference (V) between any two points on a conductor to the current (I) flowing between them, is constant, provided the temperature of the conductor does not change.’
In other words V/I = constant
or V /I = R
Where R is the resistance of the conductor between the two points considered
Put in another way, it simply means that provided R is kept constant, current is directly proportional to potential difference across the ends of the conductor. For a constant value of R, if the value of V is increased, the value of I increases; if V is decreased, then I decreases. Also notice that if Vis constant and R is increased, I decreases. Similarly, if V is constant and R is decreased, I increases.
Figure show the current voltage relationship for R=10 ohm.
Material that obeys Ohm's Law is called 'ohmic' or 'linear' because the potential difference across it varies linearly with the current. However this linear relationship between V and I does not apply to all non-metallic conductors.
