Learn the dielectric constant in physics—definition, formula, units, values, and key uses for JEE/NEET 2025 exams. Learn what is dielectric constant , how to calculate it, and what factors affect it. Find out the values of dielectric constant for different materials and their applications in capacitors and electronics. The dielectric constant shows how well a material holds electric charge. It compares this ability to a vacuum. You can find it using the formula κ = ε/ε₀. Here, ε is the material’s permittivity, and ε₀ is free space’s permittivity (about 8.854 x 10⁻¹² F/m). This value is important in electromagnetism. Relative permittivity is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. It measures the ability of the material to store electric energy in an electrical field and is also known as dielectric constant .
