Electric Current through a Solid Conductor PQ

Electric current refers to the flow of electric charge through a conductor. When a potential difference is applied across a conductor, electric charges start to move. In this case, we consider a solid conductor PQ through which electric current is flowing.

Electric Current

Electric current is defined as the rate of flow of electric charge through any cross-section of a conductor. It is denoted by the symbol ‘I’ and is measured in amperes (A). Mathematically, electric current is given by the formula:

I = Q/t

Where Q is the amount of charge flowing through any cross-section of the conductor in time t.

Ohm’s Law

Ohm’s law states that the current flowing through a conductor is directly proportional to the potential difference across it, provided the physical conditions of the conductor remain constant. Mathematically, Ohm’s law is represented as:

V = IR

Where V is the potential difference across the conductor, I is the current flowing through it, and R is the resistance of the conductor.

Resistance

Resistance is defined as the opposition offered by a conductor to the flow of electric current through it. It is denoted by the symbol ‘R’ and is measured in ohms (Ω). The resistance of a conductor depends on its physical properties such as its length, cross-sectional area, and the material from which it is made.

Factors Affecting Resistance

The resistance of a conductor depends on various factors such as:

- Length: The longer the conductor, the greater is its resistance.
- Cross-sectional area: The greater the cross-sectional area of the conductor, the lower is its resistance.
- Material: Different materials have different resistivities and hence different resistances.

Conclusion

In conclusion, electric current through a solid conductor PQ is determined by the potential difference applied across it and the resistance offered by the conductor to the flow of electric charge. The resistance of a conductor depends on its physical properties such as its length, cross-sectional area, and the material from which it is made. Ohm’s law governs the relationship between the potential difference, current, and resistance of a conductor.