Ohm's Law
Category : JEE Main & Advanced
If the physical conditions of the conductor (length, temperature, mechanical strain etc.) remains some, then the current flowing through the conductor is directly proportional to the potential difference across it's two ends i.e. \[i\propto V\] \[\Rightarrow \] \[V=iR\] where R is a proportionality constant, known as electric resistance.
(1) Ohm's law is not a universal law, the substances, which obey ohm's law are known as ohmic substance.
(2) Graph between V and i for a metallic conductor is a straight line as shown. At different temperatures V-i curves are different.
(3) The device or substances which don't obey ohm's law e.g. gases, crystal rectifiers, thermoionic valve, transistors etc. are known as non-ohmic or non-linear conductors. For these V-i curve is not linear.
Static resistance \[{{R}_{st}}=\frac{V}{i}=\frac{1}{\tan \theta }\]
Dynamic resistance \[{{R}_{dyn}}=\frac{\Delta V}{\Delta I}=\frac{1}{\tan \varphi }\]
You need to login to perform this action.
You will be redirected in
3 sec
