State and explain Ohm.s law and hence defined one ohm.

Explanation

At constant temperature the current passing through a conductor is proportional to the potential difference between its ends.
If I is the strength of current flow through the conductor when the p.d. across its ends is V volt. Then `I prop V`
V=IR
R is a constant called electrical resistance. Its value depends on the nature of the material of conductor, dimensions and temperature of the conductor. Ohm.s law gives the relation between the current and voltage. It is not a universal law. It is not applicable for all substances. It is applicable only at constant temperature.