2 1-10.     What is the principal advantage of an indirectly heated cathode over a directly heated cathode?   1.    It is larger   2.    It is immune to ac heater current variations   3.    It reaches an operating temperature more quickly   4.    It has a lower operating temperature 1-11.     When you view an electron tube and its socket connection from the bottom, in what direction are (a) the pins of the tube and (b) the pins of the socket numbered?   1.    (a) Counterclockwise (b) Clockwise   2.    (a) Counterclockwise   (b) Counterclockwise   3.    (a) Clockwise   (b) Counterclockwise   4.    (a) Clockwise   (b) Clockwise 1-12.     Electron tubes are identified by a number preceded by which of the following letter designations? 1.    T   2.    V   3.    ET   4.    VT 1-13.     The getter in an electron tube serves what purpose? 1.    It protects the plate from overheating   2.    It allows the cathode to emit more electrons   3.    It helps to produce a better vacuum   4.    It anchors the tube elements in the base _______________________________________ IN ANSWERING QUESTIONS 1-14 THROUGH 1-16, MATCH EACH TERM LISTED IN COLUMN A WITH ITS ASSOCIATED ELECTRONIC SYMBOL LISTED IN COLUMN B. A. TERMS   B. SYMBOLS   1-14.   Dc plate resistance     1.    E_p   1-15.   Dc plate current   2.    e_p   1-16.   Dc plate voltage   3.    I_p   4.    R_p _______________________________________ Figure 1A. E_p I_p characteristic curve.   IN ANSWERING QUESTIONS 1-17   THROUGH 1-23, REFER TO FIGURE 1A. 1-17.     The area of the graph that lies between points C and D is referred to as   1.    nonlinear   2.    straight   3.    linear   4.    curved