What is conductivity of a material?

Conductivity is a material property that allows it to carry electricity through it. Conductors, insulators, and superconductors are the three types of materials classed by conductivity.
Conductors are materials with high electron mobility, while insulators have low electron mobility. A good electrical conductor allows electrons to flow freely.

Electrical Conductor

A conductor is a material that allows electrical current to pass. The current supply can go in one or more directions. Common metals are used to make electrical conductors. The capacity to conduct electricity is known as electrical conductivity.

A conductor is a type of metal that permits electrical current to flow through it. Conductors are metals that allow electrical charges to pass through them, such as aluminum, copper, and a few other alloys. An electrical charge passes between the atoms when potential differences across the conductor are applied.

Various factors, such as atmospheric conditions, tensile strength, conductivity, fatigue strength, and others, determine whether metals are good, conductors. The conductors' surfaces have free electrons that allow current to flow, giving them the ability to create electricity.
Stranded power distribution wires are strong and flexible. The core of wire in stranded conductors is usually built with many wire layers ranging from 6 to 24 wires where each strand's diameters and the copper cross-sectional area that corresponds to conductor size are known.

The following are some examples of electrical conductors:

• Copper
• Aluminium
• Silver
• Gold
• Graphite
• Platinum, etc.

Types of Conductors

Metals

Metals are the most common conducting materials utilized in practical applications. Copper wires or their alloys, for example, are most likely used as conducting elements in the wire around the house. Metal is employed in electric plugs and the internal mechanism of your electric irons as a conducting substance. Because metals have many free electrons, which increase the mobility of the charge.
A metal's conductivity results in the increase of free electrons. Silver, compared to copper and gold, has a higher electrical conductivity. Copper is used in household appliances and circuits because silver is significantly more expensive.
Aluminum is also a good electrical conductor; however, it has lower conductivity than copper. It is most commonly used in conjunction with copper in-home wiring.

Non-Metals

Non-metals, on the other hand, are generally poor electrical conductors. Some non-metallic materials are excellent electrical conductors. In the form of graphite, Carbon is an excellent electrical conductor. Only three of the four carbon atoms are used for bonding in graphite's structure. One electron is available as a free electron as a result of this arrangement.

Non-metals have the following characteristics.

• Non-metal atoms are often smaller than metal atoms. The atomic sizes of non-metals determine the number of properties.
• Electro-negativity is high in non-metals. That means that non-metal atoms have a significant propensity to attract more electrons than they would otherwise have.
• Electrical conductivity is significantly poor in non-metals. The most important attribute distinguishing non-metals from metals is their low or absent electrical conductivity.
• Some non-metals exist as gases, while others exist as solids, and one exists as a liquid under typical conditions of temperature and pressure. At room temperature, however, all metals except mercury are solids. Because so many non-metals are liquids or gases, their melting and boiling temperatures are often low under normal atmospheric circumstances.

Ionic Conductors

Ionic conductors are conductors that are in the form of a solution. For example seawater and saltwater are good electrical conductors, they are the best examples of ionic conductors.

Properties of Ionic Conductors

• It requires lot of energy to break the ionic compounds as they posses a high melting and the boiling point.
• Ions are formed by electrostatic forces of attraction between oppositely charged ions.
• Ionic substances form crystals.
• These compounds are fragile and can easily shatter into small fragments.
• Electrovalent substances are soluble in water but insoluble in solvents such as oil, petrol, and kerosene.
• Ionic compound conducts only in the molten state and not in the solid state.
• Ionic compounds have greater enthalpies of fusion and vaporization than other molecules.

Semi-conductors

Semi-conductors are the elements whose conductivity is in middle of the conductors and the insulators. Because semiconductors are not as good at conducting electricity as conductors, they have applications by adding some impurity to them. Germanium (Ge) and Silicon (Si) are examples of such semiconductors.

Properties of Semiconductors

• At zero Kelvin, a semiconductor serves as an insulator. It acts as a conductor when the temperature rises.
• Semiconductors can be doped to make semiconductor devices suited for energy conversion, switches, and amplifiers due to their excellent electrical properties.
• There are fewer power losses.
• Semiconductors are smaller and lighter than transistors.
• As the temperature rises, the resistance of semiconductor materials lowers, and vice versa.

Properties of Electrical Conductors

When a conductor is at equilibrium, it has the following properties:

• The flow of electrons and ions in a conductor is always possible.
• A conductor's electric field is zero, allowing electrons to move freely within it.
• A conductor's charge density is zero.
• Free charges exist only on the conductor's surface.
• A conductor's points all have the same potential.

Many metals are excellent electrical conductors. That is why metals are used in appliances that require passing electricity. Insulators are plastic coverings that wrap electrical conductors. It protects us from being shocked by electricity.

As a result, this is all about stranded electrical conductors used in power transmission. Compared to a single wire with the same cross-section region, these conductors have a lot of flexibility and mechanical strength. The central wire is usually enclosed by the different layers of wires in these conductors. The conductor size is determined by the copper cross-section region that corresponds to it, the number of strings, and the diameter of each string.

The following qualities should be present in most good current-carrying conductors:

• High conductivity/low resistance.
• Low resistivity coefficient at low temperatures.
• Thermal conductivity is good.
• It should be simple to obtain.
• It should be extremely malleable.
• Adaptable to the production process.
• Shapes, rods, and wires are all readily available.
• Viability in terms of money.

Uses of Conductors

• Conductors are mostly utilized in real-world situations from transmission to electronics circuit.
• Aluminum: Aluminium conductor steel reinforced (ACSR) are used in long transmission line.
• Steel: The steel is used as a conductor in the high voltage transmission line.
• In automotive conductors are used for operation of various circuitry in the vehicle.
• Used in power transmission research work

Common Mistake

Using bad conductor: When there is a short circuit or overloading, it may catch fire due to bad conductors, so use good conductors to avoid fire.

Overloading: At home, make sure that all equipment does not start at a time; it may be overloaded.

Earthing is not proper: When earthing is not proper, then it is risky, and any person can get electric shock.

Making wire shorts in projects: Make sure that wire is not shorted in any project because the project will not work properly and may get damaged.

Use different wire gauges: Use the same wire gauges while handling any project or housework.

Related Concept

• Insulators
• Semiconductors

Context and Applications

In each of the expert exams for undergraduate and graduate publications, this topic is mainly studied in:

• Bachelor of technology in Electrical Engineering
• Master of technology in Power Engineering

Practice Problem

Q1. A _____________ is an object or material that allows electrical current to pass.

A. Conductor

B. Insulator

C. Both A and B

D.None of these.

Answer: A

Explanation: Because conductors are materials with high electron mobility, while insulators have low electron mobility, a good electrical conductor is one that allows electrons to flow freely.

Q2. ___________ is the good conductor of electricity.

A. Aluminum

B. Copper

C. Bronze

D. Plastic

Answer: Copper

Explanation: A Copper conductivity results in the increase of free electrons increases. Copper is used in all household appliances and circuits due to the fact that silver is significantly more expensive.

Q3. Properties of Electrical conductor are:

A. The flow of electrons and ions in a conductor is always possible.

B. Electric field inside a conductor is zero, allowing electrons to move freely within it.

C. A conductor's volume charge density is zero.

D. All of these

Answer: D

Explanation: All are the properties of conductors.

Q4. Qualities of good current-carrying conductors are...

A. High conductivity/low resistance.

B. Low resistivity coefficient at low temperatures.

C. Thermal conductivity is good.

D. All of the above.

Answer: D

Explanation: The conductor should have all the mentioned qualities to increase efficiency.

Q5. Glass is the example of..............

A. Metal

B. Non-Metal

C. Insulator

D. Ionic Conductor

Answer: C

Explanation: Because glass has the highest resistance, they are considered an insulator.