Magnetic field — UPSC Physics Optional CSE 2009 Paper II

A type-II superconducting material with superconducting transition temperature T_c is placed in a magnetic field. What is the material state (normal or superconducting or mixed) for (i) T < T_c ; \quad H > H_{c_2} (ii) T > T_c ; \quad H < H_{c_1} (iii) T < T_c ; \quad H_{c_1} < H < H_{c_2} (iv) T < T_c ; \quad H < H_{c_1} (v) T > T_c ; \quad H > H_{c_2} where H_{c_1} and H_{c_2} are the lower and upper critical fields for a type-II superconductor.