101. Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases. Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive device.
102. Which of the following elements act as donor impurities? GoldPhosphorusBoronAntimonyArsenicIndium Select the answer using the following codes :
103. Light dependent resistor is
104. The breakdown voltage in a zener diode
105. A varactor diode is used for
106. One eV = 1.602 x 10-19 joules.
107. Assertion (A): When VDS is more than rated value the drain current in a JFET is very high. Reason (R): When VDS is more than rated value, avalanche breakdown occurs.
108. If ib is plate current, eb is plate voltage and ec is grid voltage the v-i curve of a vacuum triode is
ib = 0.003 (eb + kec)n. Typical values of k and n are
109. In which material do conduction and valence bands overlap
110. For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in
111. Discrete transistors T1 and T2 having maximum collector current rating of 0.75 amp are connected in parallel as shown in the figure, this combination is treated as a single transistor to carry a total current of 1 ampere, when biased with self bias circuit. When the circuit is switched on, T1 draws 0.55 amps and T2 draws 0.45 amps. If the supply is kept on continuously, ultimately it is very likely that
112. The number of p-n junctions in a semiconductor diode are
113. Assertion (A): A high junction temperature may destroy a diode. Reason (R): As temperature increases the reverse saturation current increases.
114. When a diode is not conducting, its bias is
115. The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of
116. The number of valence electrons in a donor atom is
117. An electron rises through a voltage of 100 V. The energy acquired by it will be
118. A Varactor diode has
119. The most important set of specifications of transformer oil includes
120. Assertion (A): In Hall effect the O.C. transverse voltage developed by a current carrying semiconductor with a steady magnetic field perpendicular to the current direction has opposite signs for n and p semiconductors. Reason (R): The magnetic field pushes both holes and electrons in the same direction.
121. A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000 Ω. The voltage across the load resistance is zero. It indicates that
122. If the drift velocity of holes under a field gradient of 100 V/m in 5 m/s, their mobility (in SI units) is
123. The derating factor for a BJT transistor is about
124. An intrinsic silicon sample has 2 million free electrons. The number of holes in the sample is
125. Assertion (A): When reverse voltage across a p-n junction is increased, the junction capacitance decreases. Reason (R): Capacitance of any layer is inversely proportional to thickness.