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It is because when a dielectric is placed between the charges , the dielectric gets polarized and the net electric field between the two charges decreases, hence force = charge x electric field also decreases. john

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A capacitor is a device which stores energy by?

Magic. Look up capacitors on wikipedia!!A capacitor stores electrical charges in its plates.Both wrong. A capacitor stores energy as an electric field developed in the dielectric between its plates. A good dielectric with high permittivity (once called dielectric constant) concentrates this field, allowing more energy to be stored in a capacitor having the same plate area and separation but a dielectric of lower permittivity.


What is dielectric constant?

A dielectric is an insulating material that does not conduct electricity and is transparent to an electromagnetic field. Dielectric materials are used to separate conducting surfaces such as the plates inside a capacitor, wires inside transformers, electric cable conductors, and elsewhere in the electric industry where electrical separation of charged elements is necessary. The dielectric constant is a ratio of the capacitance of a capacitor in which a particular insulating material is the dielectric, to the capacitance of the capacitor in which a vacuum is the dielectric.


What is a dielectric?

In physics, a dielectric is an insulating (or very poorly conducting) material. The material can be solid, liquid or gaseous. When a voltage difference is applied to top and bottom of a cylinder filled with a dielectric, no current will flow inside the cylinder because, unlike metals, a dielectric has no free-or loosely bound-electrons that can drift through the material. Instead, electric polarization occurs. The positive charges within the dielectric are displaced minutely in the direction of lower voltage, and the negative charges are displaced minutely in the opposite direction. When the molecules constituting the dielectric are polar (like water molecules), the molecules will align in the field, thus contributing to the electric polarization. Inside the cylinder no net charge density will arise because the charges in adjacent volume elements cancel. However, at the top and bottom of the cylinder an uncanceled surface charge will appear, and this surface charge (positive at the low voltage side and negative at the high voltage side) will oppose the electric field associated with the voltage difference. Thus, the polarization of the dielectric reduces the electric field inside the dielectric. Dielectric material is characterized by an intrinsic property called relative permittivity, usually denoted by εr (formerly this was known as the dielectric constant). The relative permittivity describes the ease of the polarization of the material and determines the size of the surface charge densities at the top and bottom of the cylinder. The Coulomb force between two permanent electric point charges placed inside a dielectric medium is 1/εr smaller than it would be in a vacuum due to the polarization of the dielectric medium by the point charges. The quantity of electric energy stored per unit volume of a dielectric medium is proportional to εr. The capacitance of a capacitor filled with a dielectric is a factor εr greater than it would be in vacuum. Reference: http://en.citizendium.org/wiki/DielectricDielectric is a substance that can transport electricity without conducting it.


How do you change time constant of capacitor?

In theory ... on paper where you have ideal components ... a capacitor all by itself doesn't have a time constant. It charges instantly. It only charges exponentially according to a time constant when it's in series with a resistor, and the time constant is (RC). Keeping the same capacitor, you change the time constant by changing the value of the resistor.


What makes the capacitor to store charges?

A capacitor consists of two plates (foils ...) separated by an insulating medium. The insulating medium may be air, oil, a plastic film, and so on, and is known as the dielectric. The charge on the capacitor is actually stored by slightly distorting the molecules in the dielectric. The quality of a dielectric is measured by a factor known as K, and a higher K means that the molecule can store a larger distortion. When we discharge the capacitor, the molecules are allowed to relax to their uncharged state.

Related Questions

How does force between 2 point charges changes if the dielectric constant of medium in which they are kept increases?

If the dielectric constant of the medium between the charges increases, the force between the charges decreases. This is because increasing the dielectric constant reduces the electric field strength between the charges, leading to a decrease in the force between them.


What happens when air is replaced by a dielectric medium of constant k the maximum force of attraction between two charges separated by a distance?

In a dielectric medium with constant ( k ), the force of attraction between two charges separated by a distance decreases by a factor of ( k ) compared to in air. This is due to the polarization of the medium which weakens the electric field between the charges, thereby reducing the force between them.


What is the relation between Dipole moment and Dielectric constant?

The dipole moment is a measure of the overall polarity of a molecule due to the separation of positive and negative charges. The dielectric constant is a measure of how well a material can insulate electric fields, which is influenced by the presence of dipoles in the material. Generally, materials with higher dipole moments tend to have higher dielectric constants.


What is meant about di-electric constant?

The relative permittivity of a material is its dielectric permittivity expressed as a ratio relative to the permittivity of vacuum.Permittivity is a material property that expresses the force between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased or increased relative to vacuum.Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared to a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known as dielectric constant, a term deprecated in physics and engineering.


What is the force between two charge particle when medium is placed between them?

The force between two charged particles in a medium will depend on the properties of the medium, such as its dielectric constant. The force will be reduced compared to if the particles were in a vacuum, due to the screening effect of the medium on the electric field between the charges. The force will be weaker as the dielectric constant of the medium increases.


What is the Difference between dielectric and insulator?

The difference between dielectric and insulator lies in its field of application.Dielectrics are used to store the electric charges, while insulators are used to block the flow of electric charges ( they more or less act like a wall).While all dielectrics are insulators (they don't allow the flow of electric charges through them) all insulators aren't dielectric because they can't store charges unlike dielectrics.


What is magnetic permeability of materials?

Relative permittivity or dielectric constant of a medium is defined as the ratio of force between two charges separated by a certain distance in air or vacuum to the force between the same charges separated by the same distance in the medium.According to American Heritage Dictionary:permittivitySYLLABICATION: per·mit·tiv·i·tyPRONUNCIATION: PERM eh TIV eh TEENOUN: Inflected forms: pl. per·mit·tiv·i·tiesA measure of the ability of a material to resist the formation of an electric field within it. Also called dielectric constant, relative permittivity.


A capacitor is a device which stores energy by?

Magic. Look up capacitors on wikipedia!!A capacitor stores electrical charges in its plates.Both wrong. A capacitor stores energy as an electric field developed in the dielectric between its plates. A good dielectric with high permittivity (once called dielectric constant) concentrates this field, allowing more energy to be stored in a capacitor having the same plate area and separation but a dielectric of lower permittivity.


Why is the dielectric constant value of covalent compounds is low?

The dielectric constant of covalent compounds is low because they have strong covalent bonds that do not allow for easy separation of charges when exposed to an electric field. This limits the ability of these compounds to induce an electric field within themselves and therefore results in a low dielectric constant.


What is dielectric constant?

A dielectric is an insulating material that does not conduct electricity and is transparent to an electromagnetic field. Dielectric materials are used to separate conducting surfaces such as the plates inside a capacitor, wires inside transformers, electric cable conductors, and elsewhere in the electric industry where electrical separation of charged elements is necessary. The dielectric constant is a ratio of the capacitance of a capacitor in which a particular insulating material is the dielectric, to the capacitance of the capacitor in which a vacuum is the dielectric.


What is the coulombs force between two point charges placed in different mediums?

The Coulomb's force between two point charges placed in different mediums depends on the electric permittivity of the mediums. The force magnitude is inversely proportional to the square of the distance between the charges and directly proportional to the product of the charges. The presence of different mediums alters the force based on their respective dielectric constants.


What will happen to the electrostatic force between the two charges if a metal slab is placed between them?

The metal slab will act as a conductor and redistribute the charges to cancel out the electric field inside the slab. As a result, the electrostatic force between the two charges will decrease, since the presence of the metal slab will weaken the field between the charges.