Electric Flux Density

The electric flux density, also known as the electric displacement field, is a fundamental concept in electromagnetism. It is represented by the symbol D and is a vector quantity that describes the distribution of electric flux in a given region of space.

Definition

The electric flux density is defined as the amount of electric flux passing through a unit area perpendicular to the direction of the electric field. Mathematically, it is given by the equation:

D = εE

where D is the electric flux density, ε is the permittivity of the medium, and E is the electric field intensity.

Explanation of the Answer

The correct answer to the question is option 'A', which states that the electric flux density is the product of the permittivity and the electric field intensity.

The permittivity of a medium is a measure of its ability to store electrical energy in an electric field. It is a material property that determines the resistance of the medium to the formation of an electric field. The permittivity is denoted by the symbol ε.

The electric field intensity, represented by the symbol E, is a measure of the strength of an electric field at a particular point in space. It is defined as the force experienced by a unit positive charge placed at that point. The electric field intensity is directly proportional to the electric field created by a charge and inversely proportional to the distance from the charge.

According to Gauss's law, the electric flux passing through a closed surface is equal to the charge enclosed by the surface divided by the permittivity. Mathematically, this is expressed as:

Φ = Q/ε

where Φ is the electric flux, Q is the charge enclosed by the surface, and ε is the permittivity.

By rearranging this equation, we can express the electric flux density as:

D = Φ/A = Q/εA

where A is the area of the surface.

Since the electric flux density is equal to the electric field intensity multiplied by the permittivity, we have:

D = εE

Hence, the correct answer is option 'A' - the electric flux density is the product of the permittivity and the electric field intensity.