281. In the transistor schematic symbol, the arrow_______________?
A. is located on the emitter
B. is located on the base
C. is locate on the collector
D. points form north to south
282. The semiconductor diode can be used as a rectifier because _______________?
A. It has low resistance to the current flow when forward biased & high resistance when reverse biased.
B. It has low resistance to the current flow when forward biased.
C. It has high resistance to the current flow when reverse biased
D. Its conductivity increases with rise of temperature.
283. The device or circuit used for conversion of A.C. into D.C. is called_______________?
A. An amplifier.
B. A rectifier
C. Filtering circuit
284. The especially designed semiconductor diodes used as indicator lamps in electronic circuits are___________?
A. The switch
B. The light emitting diode
C. The photo diodes
D. Solar cells.
285. Semi-conductors with donor atoms and free electrons belong to the type________________?
D. any of above
286. In p-n-p transistor the collector current is________________?
A. equal to emitter current
B. slightly less than emitter current
C. greater than emitter current
D. any of above
287. The simplest type of rectification known as half wave rectification is obtained by____________________?
A. using a transistor
B. suppressing the harmonics in A.C voltage
C. suppressing half wave of A.C supply by using diode
D. using a Coolidge tube
288. Depletion region of a junction is formed_____________?
A. during the manufacturing process
B. under forward bias
C. under reverse bias
D. when temperature varies
289. Which one of following band is completely filled in case of conductors ?
A. Conduction band
B. Fermi band
C. Valence band
D. Forbidden band
290. The value of resistivity for insulator is of the order of____________?
A. 105 ohm metre
B. 106 ohm metre
C. 107 ohm metre
D. 108 ohm metre