Semiconductor Devices PYQs Set 8 (PDF)

Set 8 of 16 · Questions 211-240 of 467

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Mere Teacher · Previous Year Questions NEET Physics · Semiconductor Devices · Set 8 (Q211-240)
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211. $Given below are two statements : Statement I : PN junction diodes can be used to function as transistor, simply by connecting two diodes, back to back, which acts as the base terminal. Statement II : In the study of transistor, the amplification factor β indicates ratio of the collector current to the base current In the light of the above statements, choose the correct answer from the options given below.$ (1) $Statement I is false but Statement II is true.$ (2) $Both Statement I and Statement II are true.$ (3) $Statement I is true but Statement II is false.$ (4) $Both Statement I and Statement II are false.$ 212. $If a semiconductor photodiode can detect a photon with a maximum wavelength of 400nm, then its band gap energy is Planck's constant h = 6.63 \times 10^{- 34}, J . s . Speed of light c = 3 \times 10^{8} m / s$ (1) $1.1 eV$ (2) $2.0eV$ (3) $3.1eV$ (4) $1.5eV$ 213. $A person applies a sine wave and square wave to an AND gate as shown in the figure (i) and (ii). Assuming that both the voltages are applied in phase, the person observes the output at E and F on (i) and (ii), respectively. [Assume minimum voltage of 5 V is equivalent to logic (i)] Sine wave, 50 Hz, 2 V . Sine wave, 100 Hz, 8 V Square wave, 107 Hz, 6 V Sine wave, 100 Hz, 8 V$ (1) $Square wave at 50 Hz and square wave at 100 Hz .$ (2) $Sine wave at 50 Hz and square wave at 100 Hz .$ (3) $No output and sine wave at 100 Hz .$ (4) $No output and pulsed wave at 100 Hz .$ 214. $For the logic circuit shown, the truth table is [NEET 2020]$ (1) $A B C 001011101111$ (2) $A B C 001011101110$ (3) $A B C 001010100110$ (4) $A B C 000010100111$ 215. $For the given circuit shown in fig, to act as full wave rectifier, a.c. input should be connected across ........and........the d.c. output would appear across........and........$ (1) $(A), (C) and (B), (D)$ (2) $(B), (D) and (A), (C)$ (3) $(A), (B) and (C), (D)$ (4) $(C), (A) and (D), (B)$ 216. $Which logic gate is represented by the following combination of logic gates?$ (1) $AND$ (2) $OR$ (3) $NOR$ (4) $NAND$ 217. $The logic operation performed by the following circuit is$ (1) $NOR$ (2) $AND$ (3) $NAND$ (4) $OR$ 218. $For the given digital circuit, write the truth table and identify the logic gate it represents$ (1) $NAND gate$ (2) $OR gate$ (3) $AND gate$ (4) $NOR gate$ 219. $Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V_{0} changes by: (assume that the Ge diode has large breakdown voltage)$ (1) $0.8 V$ (2) $0.6 V$ (3) $0.2 V$ (4) $0.4 V$ 220. $In the circuit, the logical value of A = 1 or B = 1 when potential at A or B is 5V and the logical value of A = 0 or B = 0 when potential at A or B is 0 V. The truth table of the given circuit will be :$ (1) $A 0101 B 0011 Y 0001$ (2) $A 0101 B 0011 Y 0111$ (3) $A 0101 B 0011 Y 0000$ (4) $A 0101 B 0011 Y 1110$ 221. $Identify the correct Logic Gate for the following output (Y) of two inputs A and B.$ (1) (2) (3) (4) 222. $In the figure, given that V_{BB} supply can vary from 0 to 5.0 V, V_{CC} = 5 V, β_{dc} = 200, R_{B} = 100 kΩ, R_{C} = 1 kΩ and V_{BE} = 1.0 V . The minimum base current and the input voltage at which the transistor will go to saturation, will be, respectively :$ (1) $25 μ A and 2.8 V$ (2) $20 μ A and 3.5 V$ (3) $20 μ A and 2.8 V$ (4) $25 μ A and 3.5 V$ 223. $The given circuit has two ideal diodes connected as shown in the figure. The current flowing through the resistance R_{1} will be [NEET 2016]$ (1) $2.5 A$ (2) $10.0 A$ (3) $1.43 A$ (4) $3.13 A$ 224. $For the following logic circuit, the truth table is [NEET 2023]$ (1) $A B Y 000101111$ (2) $A B Y 001010101110$ (3) $A B Y 000010100111$ (4) $A B y 001011101110$ 225. $The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit?$ (1) $2.31 A$ (2) $1.33 A$ (3) $1.71 A$ (4) $2.00 A$ 226. $For the logic circuit shown, the output waveform at Y is$ (1) (2) (3) (4) 227. $In semiconductors at a room temperature [2004]$ (1) $The valence band is partially empty and the conduction band is partially filled$ (2) $The valence band is completely filled and the conduction band is pa1tially filled$ (3) $The valence band is completely filled$ (4) $The conduction band is completely empty$ 228. $Following diagram performs the logic function of [2003]$ (1) $XOR gate$ (2) $AND gate$ (3) $NAND gate$ (4) $OR gate$ 229. $The correct Boolean operation represented by the circuit diagram drawn is:$ (1) $NOR$ (2) $AND$ (3) $OR$ (4) $NAND$ 230. $The I-V characteristics of a p-n junction diode in forward bias is shown in the figure. The ratio of dynamic resistance, corresponding to forward bias voltages of 2V and 4V respectively, is :$ (1) $1: 2$ (2) $5 : 1$ (3) $1 : 40$ (4) $20 : 1$ 231. $The value of net resistance of the network as shown in the given figure is :$ (1) $6Ω$ (2) $(5/2) Ω$ (3) $(15/4) Ω$ (4) $(30/11) Ω$ 232. $Choose the correct logic circuit for the given truth table having inputs A and B. Inputs Output A B Y 000010101111$ (1) (2) (3) (4) 233. $In a PN ‐junction diode not connected to any circuit [2015]$ (1) $the potential is the same everywhere$ (2) $the P ‐type is a higher potential than the N ‐type side$ (3) $there is an electric field at the junction directed from the N ‐type side to the P ‐type side$ (4) $there is an electric field at the junction directed from the P ‐type side to the N ‐type side$ 234. $In the logic circuit diagram, A, B and C are the inputs, Y is the output. The output Y is 'HIGH'$ (1) $for all the inputs 'LOW'.$ (2) $when A = 1, B = 0, C = 0$ (3) $when A = 1, B = 0, C = 1$ (4) $for all the inputs 'HIGH'.$ 235. $In the figure shown, if the diode forward voltage drop is 0.2 V. the voltage difference between A and B is$ (1) $1.3 V$ (2) $2.2 V$ (3) $0.5 V$ (4) $0$ 236. $To get output '1' at R, for the given logic gate circuit the input values must be:$ (1) $X = 1, Y = 1$ (2) $X = 0, Y = 0$ (3) $X = 0, Y = 1$ (4) $X = 1, Y = 0$ 237. $Figure shows a DC voltage regulator circuit, with a Zener diode of breakdown voltage = 6V. If the unregulated input voltage varies between 10 V to 16 V, then what is maximum Zener current?$ (1) $2.5 mA$ (2) $1.5 mA$ (3) $7.5 mA$ (4) $3.5 mA$ 238. $With increasing biasing voltage of a photodiode, the photocurrent magnitude$ (1) $Increases initially and after attaining certain value, it decreases$ (2) $Increases linearly$ (3) $Increases initially and saturates finally$ (4) $Remains constant$ 239. $An n.p.n transistor with current gain β = 100 in common emitter configuration is shown in figure. The output voltage of the amplifier will be$ (1) $0.1V$ (2) $1.0 V$ (3) $10 V$ (4) $100 V$ 240. $A 5.0 V stabilized power supply is required to be designed using a 12 VDC power supply as input source. The maximum power rating of zener diode is 2.0 W . The minimum value of resistance R_{s} (in Ω) connected in series with zener diode will be$ (1) $16.5$ (2) $17.5$ (3) $18.5$ (4) $15.5$