01․ The dielectric strength of ferroelectric materials depends to a large extent on
The dielectric strength of ferroelectric materials depends to a large extent on intensity of electric field applied.
02․ The absolute permittivity of free space is given by
It is an electrical constant or ideal physical constant, which is the value of the absolute dielectric permittivity of classical vacuum. The expression of the absolute permittivity is as follows,
Here, C0 is the speed of light in free space,
μ0 is the vacuum permeability.
03․ Permittivity is expressed in
The electrical capacitance that is measured in farads is the only electrical property of the free space between two parallel plates of cross-section A in m2 separated by distance d in m. Thus, the expression of capacitor is as follows;
Hence, the unit is Farad per meter.
04․ The potential gradient across the material of low permittivity is ______________ than across the material of high permittivity.
We know that the force development by a charged particle is F = Q / (4πεd2).The electric force F and electric field E are related as F = Q × E. Therefore, if we apply this relation with first expression, we would get E = 1 / (4πεd2). Hence, for low permittivity the potential gradient is greater than the high permittivity.
05․ Materials which lack permanent magnetic dipoles are called
Materials which lack permanent magnetic dipoles are called diamagnetic. Unlike a ferromagnet, a diamagnet is not a permanent magnet. Its magnetic permeability is less than μ0 (the permeability of free space).
06․ Which of the following is the ferroelectric material ?
Ferroelectricity is a property of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. The term is used in analogy to ferromagnetism. Ferromagnetism was already known when ferroelectricity was discovered in 1920 in Rochelle salt. Potassium dihydrogen phosphate and Barium titanate are also examples of ferroelectric materials.
07․ Materials having a high dielectric constant, which is non-linear, are known as
Because of its property of electric polarization, high dielectric have non-linear electric field.
08․ In ferromagnetic materials
In ferromagnetic materials the atomic magnetic moments are parallel and in the same direction.
09․ When the atomic magnetic moments are randomly oriented in a solid its magnetic behavior is termed as
When the atomic magnetic moments are randomly oriented in a solid its magnetic behavior is termed as paramagnetic.
10․ The intensity of magnetization, M, of a ferro magnetic solid
The intensity of magnetization of a ferromagnetic solid is dependent of temperature.