41. Which one of the following phrases best describes flux density?

A. The concentration of lines of magnetic force
B. The rate of change of the number of lines of magnetic force
C. The opposition to a build-up of magnetic fields
D. The force that maintains lines of force
E. None of the above

42. Which is the most widely used semiconductor?

A. Copper
B. Silicon
C. Germanium
D. All of the above
E. None of the above

43. The transistor has a current gain of 175. If the base current is 0.1 mA, what is the collector current?

A. 1750 mA
B. 17.5 mA
C. 175 mA
D. 1.75 mA
E. None of the above

44. An intrinsic semiconductor has some holes in it at room temperature. What causes these holes?

A. Doping
B. Valence electrons
C. Free electrons
D. Thermal energy
E. None of the above

45. Which one of the following statements is true?

A. Power dissipation of a pure inductor decreases with operating frequency
B. Power dissipation of a pure inductor is at a maximum for dc source voltages
C. Power dissipation of a pure inductor increases with operating frequency
D. There is no meaningful relationship between the power dissipation of a pure inductor and its operating frequency
E. None of the above