Thermal conductivity is the property of the material which allows the heat to pass through it without any obstruction. The covalent bond between the atoms of a conductor is very weak whereas in an insulator it is very strong. The covalent bond is the chemical bond between the atoms which involve the sharing of electrons. In conductor, the electrons freely move from atom to atom whenever a potential difference is applied across it whereas, in an insulator, the electrons are fixed due to atomic level forces.
The conductivity of the conductor is high, whereas the conductivity of the insulators is low. Conductivity is the rate at which the heat or charge flows through the material.
The resistance of the conductor is very less, and hence the electrons freely move from atom to atom. The resistance of the insulator is very high. The conductor has a large number of free electrons whereas insulator does not have a large number of free electrons. The potential on the conductor remains same at all the point whereas in insulators the potential remains zero.
The resistivity of the conductor varies from high to low whereas the resistivity of an insulator is very high. Resistivity is the resisting power of the material. The conductor has positive thermal coefficient of resistance whereas the insulator has the negative thermal coefficient of resistance..
The thermal coefficient of resistance describes the change in the physical property of the material with temperature. If the resistance increases with the temperature, then it is called the positive thermal coefficient of resistance. In car radiators, conductors find their use in the eradication of heat away from the engine. The materials or substances that resist or don't allow the current to pass through them are insulators.
They are, in general, solid in nature. Often, in a number of systems, insulators are used as they do not allow heat to flow. The resistivity is the property which makes insulators different from conductors. Some good examples of insulators are wood, fabric, glass, mica, and quartz. Insulators provide protection against fire, sound, and, of course, electricity transmission. In addition, insulators have no free electrons at all. This is the predominant explanation of why they don't conduct electricity.
As it has the highest resistivity, glass is the strongest insulator. Plastic is a good insulator and is used to manufacture a variety of products. A common material used in the manufacture of tyres, fire-resistant clothing, and slippers is rubber.
Of course, this requires that electrons be removed from the object at the location of charging. A multitude of atoms in the region where the charging occurs have lost one or more electrons and have an excess of protons.
The imbalance of charge within these atoms creates effects that can be thought of as disturbing the balance of charge within the entire object. The presence of these excess protons in a given location draws electrons from other atoms. Electrons in other parts of the object can be thought of as being quite contented with the balance of charge that they are experiencing. Yet there will always be some electrons that will feel the attraction for the excess protons some distance away.
In human terms, we might say these electrons are drawn by curiosity or by the belief that the grass is greener on the other side of the fence. In the language of electrostatics, we simply assert that opposites attract - the excess protons and both the neighboring and distant electrons attract each other. The protons cannot do anything about this attraction since they are bound within the nucleus of their own atoms.
Yet, electrons are loosely bound within atoms; and being present in a conductor, they are free to move. These electrons make the move for the excess protons, leaving their own atoms with their own excess of positive charge. This electron migration happens across the entire surface of the object, until the overall sum of repulsive effects between electrons across the whole surface of the object are minimized.
Use your understanding of charge to answer the following questions. When finished, click the button to view the answers. One of these isolated charged spheres is copper and the other is rubber.
The diagram below depicts the distribution of excess negative charge over the surface of two spheres. Label which is which and support your answer with an explanation. See Answer Answer: A is rubber and B is copper. Sphere A shown a non-uniform distribution of excess charge; so sphere A must be made of an insulating material such as rubber.
Sphere B shows a uniform distribution of excess charge; one would reason that it is made of a conductor such as copper. Which of the following materials are likely to exhibit more conductive properties than insulating properties? Aluminum and silver are metals, making them good conductors.
The human body is a fairly good conductor. When wet, its an even better conductor. A and B are characteristic of positive and negative objects. As for C, both insulators and conductors can be charged.
As for D, this has nothing to do with the conductive properties of materials. As for E, neutrons are located in the nucleus and are "out of the way" of mobile electrons. Suppose that a conducting sphere is charged positively by some method. However, with an increase in temperature, the width of the forbidden energy band is decreased so that some of the electrons are liberated into the conduction band.
In other words, the conductivity of semiconductors increases with temperature. It means that they have a negative temperature coefficient of resistance. A material or an object that conducts heat, electricity, light or sound is called conductors.
Metal wires are good conductors of electricity and offer less resistance to the flow of current. Why metals conduct electricity? These free electrons move randomly in all directions inside metals.
When we apply external field these electrons can easily move in a specific direction. This movement of free electrons in a particular direction under the influence of an external field causes the flow of current in metal wires. A material that does not easily transmit energy, such as electric current or heat is called insulators.
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