A. Non-metal solids except carbon
B. Air and most other gases
C. Pure water and liquids in general except mercury
D. All of the above
A. carbon rod serves as conductor
B. carbon can resist the attack of battery acid
C. both (A) and (B)
D. either (A) or (B)
A. Silica
B. Germanium
C. Selenium
D. Gallium-arsenide
A. 1
B. 2
C. 4
D. 8
A. the heat content of the crystal
B. the temperature of the crystal
C. the stiffness of the bonds it makes with neighbors
A. the electronic concentration and the mobility of the free electrons
B. the number of valence electrons per atom
C. either (A) or (B)
D. none of the above
A. Aluminium is a noble metal
B. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium
C. No reaction with oxygen occurs ft Any of the above
A. the amplitude of vibration of the atoms varies with temperature
B. the electron density varies with temperature
C. the electron gas density varies with temperature
A. 2
B. 4
C. 7
D. 12
A. carbon crystals
B. solid carbon granules
C. pulverized coal
D. finely divided carbon black