Question 02:

 (a) When does a metal be opaque to light? Explain mathematically.

 (b) Consider a 2D electron gas system. Treat it as a quantum plasma. Determine the dielectric response function in terms of plasma frequency for this system.

 (c) You have studied different forms of magnetism, i.e., paramagnetism, diamagnetism, ferromagnetism, and antiferromagnetism. Compare their magnetic phenomenon by ONLY drawing their susceptibility versus temperature graph on the same plane/scale. 

 (d) Compare the magnetic behavior of divalent chromium doped (2%) alumina, and sodium metal.