Electrical power and resistivity

Introduction

Electrical resistivity is one of the general properties  which determine the amount of resistance present in the element for electricity power. Resistivity is the reverse of the conductivity of electric power. 

Electrical resistivity of Electric power 

Electrical resistivity is the general property that almost all elements possess, electrical resistivity is the measure that determines the amount of resistance present within an element which obstructs the flow of electrical power passing through it. Electric resistivity differs element by element and hence creates a difference in electric power. Elements are classified into 3 types through which electricity can pass by namely conductors, insulators, and semiconductors. Every class of these materials has a particular range of electrical resistivity in their electric power.

Formula and derivations of Electrical resistivity

•     Normally, Electrical resistivity is denoted by the Greek letter  (sounding ‘ Rho’),
•     The measure of the standard unit of electrical resistivity units is described by the Greek letter  at per meter. In symbol. (Sounding ‘Ohm * meter)
•   The  Electrical resistivity ( of elements can be calculated by the formula
•     In the description,

For example, let’s assume their resistance of sheet of the 2-meter square of metal ‘P’ has a resistance of 3

•     To determine the Electrical resistivity per meter of metal ‘P’ = 1.5
•       From the above illustration, we can say that metal ‘p’ has an Electrical resistivity of 1.5-ohmmeters.

Electric Resistivity of different classes

Metals

Metals or conductors let the  electric power flow through them easily and cause less resistance. Almost all metals are good conductors of electric power, due to that the metals have less electrical resistivity within them.

 The  Resistivity of electric power of metals:

Nonmetals

Nonmetals or insulators have high resistance within them which obstruct electric power to flow through them and due to that electrical resistivity is less in non-metals

Some insulators with their resistance on electric power or electric resistivity are mentioned below:

Semiconductors

The resistance in semiconductors is usually higher than metals and less than non-metals, in these mediums,several factors are determining  electrical resistivities in electric power, such as temperature, impurities, and area of the element through which the current is passing by.

Some semiconductors are with their electric resistivity are mentioned below:

Factors determining  the resistivity of electric power

Three factors affect the resistivity in metal namely temperature, area of cross-section, length (or distance) of the element.

●     Temperature

Temperature affects the thermal energy present in the element, which increases the resistance in material and as a result, the electrical resistivity of the element remains high during the presence of high temperature and vice-versa.

●     Area of element

The electric resistivity of elements increases if the metal is an insulator, wider the area more the resistance in element due to which the electrical resistivity of elements with wider area remain low and vice-versa.

●     Distance of element

The length of the element also affects the electrical resistivity, metal with more distance in it would probably have more resistance which obstructs the electricity and hence electric resistivity remains low.

Examples

Example 1:  The resistance of the element is calculated as 3 Ω, area of cross-section as 500cm2 and length as 10cm calculate the resistance against electric power present in material?

Answer:

Resistance of element = 3 Ω

Length = 10 cm = 0.10 m

Area of cross section = 500 cm2 = 0.05 m2,

Resistivity = 3 * 0.05 m2 / 0.10 m

= 0.15 m2 / 0.10 m

= 1.5

Example 2: With respect to example1, multiplying the length by 2 to determine the effect of length.

Resistance of element = 3 Ω

Length = 10 *2 cm = 0.20 m

Area of cross section = 500 cm2 = 0.05 m2 Resistivity 

= 3 * 0.05 m2 / 0.20 m

= 0.15 m2 / 0.20 m

= 0.75

By this, we can see the resistivity of the element decreased as the length was increased, this determines the effect of length as a result of electric resistivity.

Example 3: With respect to example1, Multiplying the cross area 2x to determine the effect of the cross-section area.

Resistance of element = 3 Ω

Length = 10 cm = 0.10 m

Area of cross-section = 500 * 2 cm2 = 0.10 m2 ,

Resistivity = 3 * 0.10 m2 / 0.10 m

= 3 * 0.10 m2 / 0.10 m

= 3

This illustration shows as the area of cross-section increased in example 3 then example 1. the resistivity of metal increased, you can determine the effect of an area in resistance of electric power.

Resistors

The resistor is a device that is generally used to control and perform various changes within the resistivity of any particular element. The resistor is like a pin-roller having terminals on each side and thick from the middle, resistors have four different color bands on their thicker middle section. All four bands are used to perform different functions; these functions are performed by a tactic known as resistivity color-coding, resistors are used in electric circuits. Some general uses of resistors include increasing resistance against electric power, increasing electrical resistivity of the  element, halve voltages, close transmission lines, bias active elements, etc.

Conclusion

Thus, we can conclude that the electrical resistivity of materials is critical because it allows the correct materials to be utilised in the correct locations in electrical and electronic components. Conductive materials, such as those used in electrical and general connecting wire, must have a low level of resistance.