Conductors And Insulators

We differentiate the elements around us on the basis of their physical properties such as malleability, phase, texture, colour, polarity, solubility etc. But as we know, another very important classification of elements is done on the basis of their conductivity of electric charge i.e. conductors and insulators.

If we perform a simple experiment with a battery and a small LED bulb, we will notice that when then the electric circuit between the battery and the bulb is completed using a plastic or a cotton thread, the bulb doesn’t glow, whereas if we perform the same experiment with the help of a metallic wire such as copper, the bulb starts to glow. This indicates that some of the elements enable the transfer of charge from the battery to the bulbs, while others do not. The basis of the classification of such elements is their conductivity. In this section, we will discuss these elements, the conductors and insulators.

What are Conductors?

Conductors are materials that allow free flow of electrons from one particle to another. These are elements which have electric charges in the form of electrons that are comparatively free to move inside the material. When a charge is transferred to such an element, it gets distributed across the entire surface of the object, which results in the movement of electrons in the object. The charges transferred to an electrical conductor distribute until the force of repulsion between electrons in areas of excess electrons is decreased to the minimum value. When such an object is brought in contact with another conductor, the charge gets transferred from the first conductor to the other until the overall repulsion due to charge is minimized.

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Examples of conductor

Graphite, the human body and the earth are good conductors of electricity. Some of the common conductor examples include metals such as:

  • Copper
  • Gold
  • Iron
Conductors And Insulators Examples

Conductors And Insulators Examples

What are Insulators?

Insulators are materials that hinder the free flow of electrons from one particle of the element to another. If we transfer some amount of charge to such an element at any point, the charge remains at the initial location and does not get distributed across the surface. The common process of charging of such elements includes charging by rubbing (for some elements, with the help of suitable materials) and charging by induction.

Examples of insulators

Some of the common insulator examples are given below:

  • Plastic
  • Wood
  • Glass

Differences Between Conductor and Insulators

Some key conductor and insulator differences are given in the table below.

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, aluminium and iron A few examples of an insulator are paper, wood and rubber
The electrons move freely within the conductor The 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

Conductors And Insulators Questions (FAQs)

Q1) Which of the following is the most conductive element?

  1. Copper
  2. Iron
  3. Silicon
  4. Silver

Answer: 4. Silver

Silver is the most conductive element.

Q2) Why are metals a preferred choice of material for making electrical wires?

Answer:

Metals are a preferred choice of material for making electrical wire because they are good conductors of electricity.

Q3) _____ is a measure of how well a material can oppose the flow of current through it.

  1. Resistance
  2. Conductance
  3. Capacitance
  4. Inductance

Answer: 1. Resistance

Resistance is the measure of how well a material can oppose the flow of current through it.

Q4) The material that has a resistance of zero is known as a _____.

Answer: Superconductor

Q5) What is a semiconductor?

Answer:

A semiconductor is a material whose electrical conductivity falls between that of a conductor and an insulator. Example, Germanium and Silicon

Q6) What is the purpose of lightning rods?

Answer:

The purpose of a lightning rod is to protect structures from lightning damages by blocking the surges and guiding their currents to the ground.

Q7) Which are the factors that affect the resistivity of a conductor?

Answer:

The resistivity of a conductor depends on

  • Temperature
  • The material with which the conductor is made of

Q8) Which of the following is not a conductor?

  1. Gold
  2. Wood
  3. Copper
  4. Iron

Answer: 2. wood

Wood is not a conductor.

Q9) Which of the following is an insulator?

  1. Human Body
  2. Silver
  3. Oil
  4. Earth

Answer: c. Oil

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