Resistance

The resistance of a conductor is a measurement of the conductor’s resistance to current flow. The resistance to current flow varies between conductors.

The letter R stands for resistance. A conductor’s resistance, R, is defined as the ratio of the potential difference, V, across it to the current, I, flowing through it.The ohm is the SI unit for resistance. The ohm is represented by the Greek letter omega .Resistance is measured in scalar units.When a potential difference of 1 volt is put across the ends of a conductor, it produces a current of 1 ampere to flow through it.

What is the resistance formula?

The measure of an object’s resistance to the flow of electric current is called its electrical resistance. The electrical conductance is the inverse quantity. Electrical conductance is the ease with which an electrical current can travel across a circuit. Furthermore, there are certain similarities between electric resistance and mechanical friction. Resistors are also used to describe the components of electric circuits. All of the materials, to some extent, resist current flow. 

The formula for resistance is as follows:

R = V/I

Resistance is defined as the ratio between the voltage drop across a resistor and the current flowing through it.

R stands for resistance in Ohms.

V denotes the voltage difference between the two ends of a resistor (Volts, V).

I is the amount of current that passes through a resistor (Amperes, A).

Factors affecting resistance of a conductor

Charge flow over wires is frequently compared to water flow through pipes. The frictional effects between water and pipe surfaces, as well as the resistance offered by barriers in its passage, are equivalent to the resistance offered by obstructions in an electric circuit. The water flow is hampered by this resistance, which affects both the flow rate and the drift speed. The overall amount of resistance to charge flow within a wire of an electric circuit is impacted by some clearly discernible variables, similar to the resistance to water flow.

• The resistance of a conductor is affected by its length.

A conductor’s resistance is directly proportional to its length. 

• The resistance of a conductor is affected by the cross-sectional area.

A conductor’s resistance is inversely proportional to its cross-sectional area.That is, if the cross-sectional area of a conductor is doubled, its resistance is halved.

• The effect of temperature on a conductor’s resistance.

All pure metal’s resistance increases as the temperature rises. As the temperature rises, the resistance of alloys increases only marginally. When the temperature of a metal rises, the resistance rises, but when the temperature of a semiconductor rises, the resistance lowers.

• The resistance of a conductor is affected by the type of the material.

Some materials have a low resistance, whereas others have a significantly higher resistance. Copper, silver, aluminium, and other low-resistance metals have a higher resistance than nichrome, constantan, and other high-resistance metals. Heating elements for heaters, toasters, electric irons, and other appliances are made of nichrome.

      As a result, the resistance, R, of a given conductor is as follows:

          1.Its length, l is directly proportional to it (R∝ l).

2.Is inversely proportional to A (R ∝ 1/A), its cross-sectional area.

3.It is dependent on the type of material used or the resistivity of the material ρ.

4.Temperature has an impact on it.

Resistance calculator with example

We can understand the example to get the knowledge about how resistance is calculated.

Example:A resistor in an electric circuit has a current of 4.00 A flowing through it. The voltage drop across the resistor from one end to the other happens to be 120 V. What is the worth of resistance?

Making use of the resistance formula

As R = V/I, R = 120V/4A.

30.O

As a result, the resistor in the circuit has a resistance of 30

Conclusion

Resistance is encountered by an electron moving across the wires and loads of the external circuit. The flow of charge is hampered by resistance. The travel of an electron from one terminal to the next is not a straight line. Rather, many collisions with fixed atoms within the conducting substance result in a zigzag pattern. The electrons run into resistance, which slows them down. While the electric potential difference between the two terminals favors charge transfer, it is resistance that prevents it. The combined influence of these two factors determines the rate at which charge flows from terminal to terminal.