What is the correct definition and formula of ohms law.? 

Ohm's law states, "Current flowing through a conductor is directly proportional to the potential difference applied across the ends of the conductor at constant temperature & pressure and for same physical conditions, i.e. for same length and cross-section of the wire."

V=IR, where R is known as the resistance of the conductor which depends on:

1. The material of the wire

2. Length and cross-section of the wire

3. The temperature of the wire

Definition: Ohms law states that the current flowing through a conductor is directly propotional to the potential difference between the ends of the conducting material.

Formula: V=IR, V is the voltage or potential difference across the conducting material.I is the direct current flowing through it.R is the resistance of the conducting material.

For a given value of resistance (ohmic conductor), the current flowing through the conductor is directly proportional to the potential difference that exists between the ends of the conductor. V=IR holds true only for ohmic conductors viz., Conductors whose resistance is independent of the voltage applied and is a constant.

Ohm's law states that the current flowing through a conductor is directly proportional to the voltage maintained between the two ends of the conductor.

The constant of proportionality is called Resistance.

V = I * R

Voltage = Current * Resistance

Resistance is the slope of the graph drawn between Voltage and Current

Consider an example in which an experiment is conducted in order to obtain the graph between voltage across two ends and current flowing through the conductor. Let's assume that the data of Voltage and Current is as below:

In this example the slope is 2 units, therefore the resistance is 2 units