3 1-21.   Electrons are NEVER found in which of the following bands? 1.    Energy band 2.    Valence band 3.    Forbidden band 4.    Conduction band 1-22.   What determines whether a substance is an insulator, semi-conductor, or conductor? 1.    The separation between the valence and forbidden bands 2.    The separation between the conduction and valence bands 3.    The separation between the conduction and forbidden bands 4.    The separation between the forbidden band and the energy gap Figure 1A.—Energy level diagram. IN ANSWERING QUESTIONS 1-23 AND 1-24, REFER TO FIGURE 1-A. 1-23.   What energy level in figure 1-A is classified as the best insulator? 1.    A 2.    B 3.    C 4.    D THIS SPACE LEFT BLANK INTENTIONALLY. 1-24.   When the insulator is compared to the semiconductor, (a) which one requires the least energy to move an electron and (b) from which point in the energy level in figure 1-A does the electron leave in its travel to the conduction band? 1.    (a) Semiconductor   (b) Valence band 2.    (a) Insulator (b) Valence band 3.    (a) Semiconductor   (b) Forbidden band 4.    (a) Insulator (b) Forbidden band 1-25.   Which of the following terms applies to the process that holds the atom together in a crystal? 1.    Suhl effect 2.    Superposition 3.    Boundary defect 4.    Covalent bonding 1-26.   The movement of electrons in a semiconductor toward the applied voltage is termed 1.    hole flow 2.    positive conduction 3.    negative conduction 4.    electron current flow 1-27.   When the theory of semiconductors is discussed, what term(s) is/are used to describe the current that flows in the semiconductor? 1.    Hole flow 2.    Electron flow 3.    Both 1 and 2 above 4.    Electromotive flow 1-28.   What process takes place within the semiconductor to cause hole flow? 1.    The breaking of covalent bonds 2.    The combining of valence bands 3.    The flexing of the material 4.    The splitting of atoms