Ohm’s Law And Limitations of Ohm’s Law

Ohm's Law

Ohm’s law states the relationship between electric current and potential difference. The current that flows through most conductors is directly proportional to the voltage applied to it. Georg Simon Ohm, a German physicist was the first to verify Ohm’s law experimentally. One of the most basic and important laws of electric circuits is Ohm’s law.
Ohm’s law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.
Mathematically, this current-voltage relationship is written as,
Ohm's Law Equation
In the equation, the constant of proportionality, R, is called Resistance and has units of ohms, with the symbol Ω.
The same formula can be rewritten in order to calculate the current and resistance respectively as follows:

Ohm's Law Equation
Ohm’s law only holds true if the provided temperature and the other physical factors remain constant. In certain components, increasing the current raises the temperature. An example of this is the filament of a light bulb, in which the temperature rises as the current is increased. In this case, Ohm’s law cannot be applied. The lightbulb filament violates Ohm’s Law.
Ohm’s Law Statement: Ohm’s law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant. Ohm’s Law Equation: V = IR, where V is the voltage across the conductor, I is the current flowing through the conductor and R is the resistance provided by the conductor to the flow of current.

Analyzing rows 1, 2 and 3, we come to understand that doubling and tripling the voltage leads to doubling and a tripling of the current in the circuit. Likewise, when we compare rows 1 and 4 and rows 2 and 5, we come to understand that doubling the total resistance serves to halve the current in the circuit. Water Pipe Analogy for Ohm’s Law Ohm’s Law describes the current flow through a resistance when different electric potentials (voltage) are applied at each end of the resistance. Since we can’t see electrons, the water-pipe analogy helps us understand the electric circuits better. Water flowing through pipes is a good mechanical system that is analogous to an electrical circuit.

Here, the voltage is analogous to water pressure, the current is the amount of water flowing through the pipe, and the resistance is the size of the pipe. More water will flow through the pipe (current) when more pressure is applied (voltage) and the bigger the pipe (lower the resistance).

Experimental Verification of Ohm’s Law
Ohm’s Law can be easily verified by the following experiment:
Apparatus Required:
Resistor
Ammeter
Voltmeter
Battery
Plug Key
Rheostat