116. At 300ºK, the forbidden energy gap in germanium is :
(a) 0.543 eV
(b) 0.632 eV
(c) 0.72 eV
(d) 0.89 eV
117. Semiconductors in pure form are poor conductors because :
(a) They have no valence electrons
(b) All valence electrons are in electron pairs
(c) They have a large number of holes
(d) They have fewer electrons than protons
118. When a pure semiconductor is heated :
(a) It becomes metal
(b) Its atomic structure collapses
(c) Its resistance increases
(d) Its resistance decreases
119. In a pure semiconductor, electric current is due to :
(a) Holes
(b) Electrons
(c) Both holes and electrons
(d) Valence electrons
120. The n type impurity :
(a) Can be added to Ge but not to Si
(b) Can be added to Si but not to Ge
(c) Creates excess holes
(d) Creates excess electrons
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