Electrical Resistance II

Electrical Resistance II

Any kind of stoppage, hindrance or prevention to movement of electron is known as Resistance.  A material is opposed to move very strongly by the flow of current or charge. Electrical Resistance measures how strong are the hindrance to the flow of current.  When an electron flows through wires, it faces resistance.

When an electron moves from one end to another end, it does not follow a direct course rather follows an irregular route. While travelling, they come in contact with innumerable atoms and also their movement is hindered by resistance.

When movement of electric charge is readily allowed, it is said to be in low resistivity.  There is a electric potential difference between two terminals. While on the one hand the difference instigates the electric charge to move but on the other hand the resistance holds it back.

Now we will try to Define Electrical Resistance. According to the Definition of Electrical Resistance, it is nothing but the ratio of voltage enforced to the electrical current that moves through it. To Define the same, we can use a simple formula.

The formula of the Definition of Electrical Resistance is as follows:

R=V/I

In order to understand the behavior of the material, Ohm’s laws can be used if the resistance is found to be uniform over a great extent of voltage. The formula of Ohm’s law is I=V/R.

The unit of Electrical-Resistance is ohm.  The unit ohm is derived from German physicist Simon Ohm who is the discoverer of the famous Ohm’s Law. The above mentioned Definition of Electrical ‘R’ includes DC current; the same Definition of Electrical R’ can be used for AC application.

According to the Definition of Electrical-Resistance, the resistance depends on temperature.  Again Electrical R’ of longer wires is always more compared to wire of larger cross section.

These also rely on material of the wire. The material is important because some materials are good conductors of electricity and thus they offer less Electrical-Resistance.  For example silver is known to be the best conductor of electricity but people cannot afford to use silver as it is too costly. So we can say that the length of the wire will affect the total amount of Electrical R’.

Copper and aluminum is used to make wires as they are known as suitable conductors. Resistivity of a material decides the conducting ability of a material.

The temperature and the structure of the material are also the factors on which the resistivity depends.  Lower resistivity materials offer less Electrical-Resistance while materials with higher resistivity offer more Resistance.  With respect to resistivity, Electrical R’ can be stated with the help of a formula:

R=R = ρlA

Where, R stands for the Resistance of the material

p stands for the resistivity of the material

l stands for the length of the material

A stands for the cross sectional area of the material

In order to find out the Electrical Resistance of Air, we should keep in mind that Resistance is dependent on the resistivity of the element. Electrical R’ of Air 1.3 × 10^16 to 3.3 × 10^16 Ω-m at 200 C when there is no ions in the gas the Electrical-Resistance of Air is infinity.