Polarization and Electric Field

Polarization is a property of dielectric materials and refers to the alignment of the electric dipoles within the material in response to an applied electric field. When an electric field is applied to a dielectric material, the electric dipoles within the material tend to align themselves with the field. This alignment results in the creation of an induced dipole moment in the material, leading to the polarization of the material.

Electric Susceptibility

The electric susceptibility of a material is a measure of how easily it can be polarized by an electric field. It quantifies the degree of polarization that occurs in a material when subjected to an applied electric field. Mathematically, electric susceptibility is defined as the ratio of polarization per unit volume to the applied electric field:

Electric susceptibility (χ) = Polarization (P) / Electric field (E)

Where:
- Electric susceptibility (χ) is measured in SI units of Farads per meter (F/m)
- Polarization (P) is measured in SI units of Coulombs per square meter (C/m²)
- Electric field (E) is measured in SI units of Volts per meter (V/m)

Explanation of the Answer

The provided answer, option 'A' (electric susceptibility), is correct because the polarization per unit applied electric field is indeed given by electric susceptibility. Electric susceptibility quantifies the extent to which a material can be polarized in response to an applied electric field. It measures the ratio of polarization to the electric field strength.

The other options mentioned in the question are not correct:
- Option 'B' (electric polarization) is incorrect because polarization itself is the phenomenon being measured and is not the quantity that describes the polarization per unit electric field.
- Option 'C' (dielectric constant) is incorrect because dielectric constant is a measure of a material's ability to store electrical energy in an electric field, but it does not directly describe the polarization per unit electric field.
- Option 'D' (magnetic susceptibility) is incorrect because it refers to the degree to which a material can become magnetized when placed in an external magnetic field and is unrelated to the polarization of a material in an electric field.

In summary, the correct answer is option 'A' (electric susceptibility) because it quantifies the polarization per unit applied electric field in a dielectric material.