Content Strategy Manager
Electrical Insulators are materials that restrict the free flow of electrons from one particle to the other. If some amount of charge is transferred to an element at any point, the charge stays at the initial location and is not distributed across the surface. The process of charging of such elements involves Charging by Rubbing and Charging by Induction.
| Table of Contents |
Key Terms: Charge density, Electric charge, Electric field, Surface charge density, Resistence, Insulation, Charging by Induction, Electrons, Ohm, Electrical insulator
What are Electrical Insulators?
[Click Here for Sample Questions]
Electrical insulators make high electric charges non-conductive. Key properties of electrical insulators are:
Resistivity: When two volt produce 2 amperes of current, the electrical insulator should also produce 1 ohm of resistance. Thus, electrical insulator materials, such as glass, paper, wood, etc. prevent electrons' conductivity from passing through.
Dielectric Strength: The electrical insulator materials should have been mechanically strong to withstand and carry the tension and weight of electrical conductors. They should be able to provide insulation as well as withstand the pressure without breakdown or failure.
Electrical insulators
Electrical Conductors
Electrical conductors are those materials that let the electricity flow through them easily. Electrical conductors permit the flow of charges through them with ease. Conductors as the name suggests have the characteristics of conductivity which tells that they can conduct electricity.
The effectiveness of the insulators is determined based on how much resistance they offer to the flow of electricity. The property which is opposite of conductivity is known as resistivity.
Electrical conductors
The video below explains this:
Semiconductors and Insulators Detailed Video Explanation:
Also check:
Electrical Insulator Examples
[Click Here for Previous Year Questions]
Here are some examples of electrical insulator materials:
- Wood
- Glass
- Plastic
- Rubber
- Styrofoam
- Air
- Rubber
- Teflon
- Mica
- Asphalt
- Quartz
Most of the non-metals are good insulators and are poor conductors of electricity. They do not have free electrons which are necessary for conducting electricity. Those materials which have larger resistivity values offer greater resistance to the flow of electricity.
For example, glass has a resistivity value of 1012 Ωm (ohmmeter), and copper has a value of resistivity of 10-12 Ωm.
Characteristics that Affect the Effectiveness of Electrical Insulators
- High resistivity
- Breakdown voltage
- Atomic structure
- Air permeability
Usually, insulators are used where we have to stop the flow of electricity. Movable electric charges are responsible for the conduction of electricity but insulators lack these electric charges. They are mainly used as a part of the electrical equipment.
The electric wires which are used for the transfer of electricity commonly seen in households are covered with the insulators so that anyone does not feel the electric current even if it is touched. The insulated coverings of the electrical plugs prevent the flow of electricity from a metal socket to the body.
Read Also:- Electric Dipole
Uses of Electrical Insulators
[Click Here for Sample Questions]
The main use of electrical insulators can be seen in homes, streets, and offices. Electrical insulators are used in types of equipment and appliances where the flow of electricity is not needed. There is a vast use of electrical insulators.
Electrical insulators stop electric devices from generating high voltage. If the human skin comes in touch with an active naked wire it will conduct the electric charges and current would be felt. Therefore insulators are used upon the naked wires which stop the flow of electric charges. Insulators are used in a lot of places.
Common uses of electrical insulators are given below:
- Stops the production of high voltage in an electric circuit.
- Helps in mitigating the cost of energy
- Saves the environment by controlling the emission of pollutants
- Improves process performances
- Prevents electric shocks or electrocution
- Allows soundproofing of appliances
Application of Electric Insulators
[Click Here for Previous Year Questions]
Some key applications of electric insulators are given below:
- Coating of electric wires
- Coating for electric poles on the streets
- Circuit boards
- Coating of cables
- High voltage appliances
Also Check:- Electric Charges and Fields Important Pointers PDF
Types of Electrical Insulators
[Click Here for Sample Questions]
Electrical insulators are classified into three types of insulation based on their operating voltage levels and applications.
Pin Type Electrical Insulators
It is the best type of electrical insulator which is used for the support of low voltage. A single piece of pin insulator is used in 11kV, and the double piece is applied to 25kV. The shell of the electrical insulator is made up of porcelain.
Pin Type Electrical Insulators
Suspension Type Electrical Insulators
Suspension insulators are used for high-voltage transmission lines. The arrangement of such types of insulators depends upon the weather conditions, the size of the insulator, and voltage.
Suspension Type Electrical Insulators
Also Read:
Previous Year Questions
- In the given circuit, what will be the equivalent resistance between the points…. [JIPMER 2006]
- Two long current carrying thin wires, both with….[JEE Main 2015]
- The value of A such that the electric field in the region between the spheres will be constant, is….[JEE Main 2016]
- A charge Q is distributed uniformly in a sphere ….
- Which of the following does not show electrical conductance?
- If a charged spherical conductor of radius 10 cm has potential V at a point distant….
Things to Remember
- Electrical conductors are those materials that let the electricity flow through them easily.
- Insulators are those that do not permit the electric charges to flow freely through them.
- Electrical insulators are used in types of equipment and appliances where the flow of electricity is not needed.
- Most of the non-metals are good insulators and are poor conductors of electricity. They do not have free electrons which are necessary for conducting electricity.
- Pin type Electrical Insulator is the best type of electrical insulator which is used for the support of low voltage.
Sample Questions
Ques. An uncharged insulated conductor A is brought near a charged insulated conductor B. What happens to the charge and potential of B? (2 Marks)
Ans. On bringing uncharged conductor A near a charged conductor B, charges are induced on A as shown in the figure below. As a result, the potential of conductor B is slightly lowered but the charge on it remains unchanged.
Ques. What are the advantages of Polymer Insulators? (2 Marks)
Ans. The main advantages of polymer insulators are given below:
- Polymer insulators are very lightweight when compared to glass and porcelain insulators.
- When compared to porcelain insulators it has a higher tensile strength
- Polymer Insulators perform better, especially in the polluted areas
- Polymer insulators are hydrophobic and so less cleaning is required
- It has a lower installation cost.
Ques. What are the properties of insulating material? (2 Marks)
Ans. The properties of insulating material are given below:
- Insulating materials must be strong enough to carry the weight of the conductors.
- Insulating materials must be free of unwanted impurities.
- The insulating material must not be porous
Ques. What are the disadvantages of glass insulators? (2 Marks)
Ans. The disadvantages of glass insulators are given below:
- The moisture easily gets condensed on the glass surface of the glass insulator therefore air dust will get deposited on the wed glass surface which will provide a path to the leakage current of the system which provides a way to the leakage current of the system.
- Due to irregular shapes glass cannot be molded in irregular shapes due to irregular cooling regular strains are caused.
Ques. Mention the name of 10 insulators. (2 Marks)
Ans. The name of 10 electrical insulators are given below:
- Wood
- Glass
- Plastic
- Rubber
- Styrofoam
- Air
- Rubber
- Teflon
- Mica
- Asphalt
Ques. Figure shows a sheet of aluminium foil of negligible thickness placed between the plates of a capacitor. How will its capacitance be affected if (3 Marks)
(i)the foil is electrically insulated?
(ii)the foil is connected to the upper plate with a conducting wire?
Ans. 
(i) The system will be equivalent to two identical capacitors connected in series combination in which two plates of each capacitor have separation half of the original separation.
Thus, new capacitance of each capacitor
C’ = 2C [∴ C ∝ \(\frac {1} {d}\)]
∴ C and C’ are in series
⇒ Cnet = \(\frac {2C * 2C} {2C + 2C} = C\)
Cnet = C = Original capacitor
(ii) System reduces to a capacitor whose separation reduces to half of the original one.
New capacitance C' = 2C
Ques. What are the key differences between conductors and insulators? (3 Marks)
Ans. The key differences between conductors and insulators are:
| Conductor | Insulator |
|---|---|
| Materials that permit electricity or heat to pass through it | Materials that do not permit heat and electricity to pass through it |
| A few examples of a conductor are silver, aluminum, and iron | A few examples of an insulator are paper, wood, and rubber |
| Electrons move freely within the conductor | Electrons do not move freely within the insulator |
| The electric field exists on the surface but remains zero on the inside | The electric field doesn’t exist |
Ques. The electrical resistance of an insulator is? (3 Marks)
Ans. Electric resistance is that property of the material that categorizes the materials into metals, insulators and semiconductors. Electrical resistance, if you may recall, is defined as the opposition offered to the flow of charges in a material.
We know that that class of materials that is known to not conduct electricity is categorized as insulators. Therefore, the insulators must quite obviously have very high electrical resistance.
In order for a material to be a perfect insulator, which is the ideal condition, it should have infinite resistance
Ques. The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why? (4 Marks)
Ans. Rubber is an insulator that does not allow an electric current to pass through the tools. Rather, charges remain confined to it. The handles of the tools like screwdrivers and pliers used by electricians for repair have the covering of plastic or rubber, for which electric current does not pass through these tools to the body of the electrician.
Now, coming to the point of what this insulator is. Materials through which charge cannot move are called insulators. Insulators are also called non-conductors. If any part of an insulator is charged, charges remain confined to that part of the insulator and do not spread all over the body.
The reason behind this is that in insulators or non-conductors electrons are tightly bound to the nucleus – they are not free electrons (they cannot move freely from one atom to another). So, electricity cannot flow through them.
For Latest Updates on Upcoming Board Exams, Click Here: https://t.me/class_10_12_board_updates
Check-Out:
Comments