Electric Fields In Material Space - Questions With Answers (Short Notes)
01. How Can Materials Be Classified In Terms Of Their Electrical Properties? Answer: Materials can be classified roughly as conductors (σ >> 1, ε r = 1) and dielectrics ( σ << 1, ε r ≥ 1 ) in terms of their electrical properties σ and ε r where σ is the conductivity and ε r is the dielectric constant or relative permittivity. A material with high conductivity ( σ >> 1) is referred to as a metal whereas one with low conductivity ( σ << 1 ) is referred to as an insulator. A material whose conductivity lies somewhere between those of metals and insulators is called a semiconductor. 02. Define Superconductor? Answer: The conductivity of metals generally increases with decrease in temperature. At temperatures near absolute zero (T = 0°K), some conductors exhibit infinite conductivity and are called superconductors. Lead and aluminum are typical examples of such metals. 03. Why...