The Relationship between Current, Charge, and Potential Difference

Direct Proportionality between Current and Potential Difference

The relationship between current and potential difference is defined by Ohm's Law. According to Ohm's Law, the current flowing through a conductor is directly proportional to the potential difference applied across it, provided that the temperature and other physical conditions remain constant. This means that as the potential difference increases, the current flowing through the conductor also increases, and vice versa.

Inverse Proportionality between Charge and Potential Difference

On the other hand, the relationship between charge and potential difference is defined by the equation Q = CV, where Q is the charge, V is the potential difference, and C is the capacitance of the system. This equation shows that the charge stored in a capacitor is directly proportional to the potential difference applied across it, but inversely proportional to the capacitance of the system.

Direct Proportionality between Current and Charge

It is also true that the current flowing through a conductor is directly proportional to the charge flowing through it, provided that the time interval remains constant. This means that as the charge flowing through the conductor increases, the current flowing through it also increases, and vice versa.

Why V is not Directly Proportional to Charge?

Although it is true that current is directly proportional to charge and potential difference is directly proportional to current, it is not true that potential difference is directly proportional to charge. The reason for this is that the potential difference across a conductor depends not only on the charge flowing through it, but also on the resistance of the conductor. In other words, the potential difference is the ratio of the work done by the electric field to move the charge through the conductor to the amount of charge moved. Therefore, the potential difference across a conductor is not solely determined by the amount of charge flowing through it, but also by the resistance of the conductor.

Conclusion

In conclusion, while there are direct proportionality relationships between current and potential difference, and between current and charge, there is no direct proportionality relationship between potential difference and charge. The potential difference across a conductor depends not only on the charge flowing through it but also on the resistance of the conductor.

V=IR, from ohm's law voltage and current are directly proportional.
and we know that,voltage is measure of energy per unit charge.i.e.potential difference is inversely proportional to charge.
and current is charge per unit time.i.e.current is directly proportional to charge.