1. : A semiconductor is formed by _______ bonds.
(A) Electrovalent
(B) Covalent
(C) Co-ordinate
(D) All of the above
2. : The most commonly used semiconductor material is _______.
(A) Carbon
(B) Sulphur
(C) Germanium
(D) Silicon
3. : The number of valence electrons in a semiconductor atom is _______.
(A) 4
(B) 2
(C) 8
(D) 3
4. : When a pure semiconductor is heated, its resistance _______.
(A) Increases
(B) Remains the same
(C) Decreases
(D) None of these
5. : When a pentavalent impurity is added to a pure semiconductor, it becomes a _______.
(A) n-type semiconductor
(B) p-type semiconductor
(C) Intrinsic semiconductor
(D) Insulator
6. : An n-type semiconductor is _______.
(A) Electrically neutral
(B) Negatively charged
(C) Positively charged
(D) None of these
7. : Addition of a trivalent impurity to a semiconductor creates many _______.
(A) Bound electrons
(B) Valence electrons
(C) Free electrons
(D) Holes
8. : A hole and an electron in close proximity tend to _______.
(A) Repel each other
(B) Have no effect on each other
(C) Attract each other
(D) All of the above
9. : The random motion of holes and free electrons due to thermal agitation is called _______.
(A) Ionization
(B) Diffusion
(C) Pressure
(D) None of these
10. : When temperature increases, intrinsic carrier concentration increases, resulting in increased _______.
(A) Infinite
(B) Capacitivity
(C) Conductivity
(D) None of these
11. : The process of increasing semiconductor conductivity by adding controlled impurities is called _______.
(A) Toxicity
(B) Excitation
(C) Attenuation
(D) Doping
12. : When an electron jumps to the conduction band, a vacancy is left in the _______ band.
(A) Valence-conduction
(B) Valence
(C) Forbidden energy
(D) Nucleus