The value of 4.5Xe + .50MV/m represents the magnitude and direction of the electric flux density vector in a given region of space. The "e" represents the unit vector in the direction of the electric field, while "MV/m" represents the strength of the electric field in terms of megavolts per meter.
Electric flux density and electric field strength are related but distinct concepts. Electric flux density is a measure of the electric field per unit area, while electric field strength is a measure of the force per unit charge experienced by a test charge in an electric field.
Yes, electric flux density can be negative. A negative value indicates that the electric field is directed in the opposite direction of the unit vector "e". This can occur near negative charges or in regions of space where the electric field is changing in direction.
The magnitude of electric flux density is affected by the electric field strength, the size and shape of the charged object, and the distance from the charged object. It is also dependent on the medium in which the electric field exists, as different materials can have different permittivity values.
Electric flux density is calculated by dividing the electric flux, which is the total number of electric field lines passing through a given area, by the area itself. It can also be calculated by multiplying the permittivity of the medium by the electric field strength.