Semiconductor Devices PYQs Set 14 (PDF)

Set 14 of 17 · Questions 391-420 of 501

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Mere Teacher · Previous Year Questions JEE Main Physics · Semiconductor Devices · Set 14 (Q391-420)
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391. $For a given transistor amplifier circuit in CE configuration V_{CC ‘} = 1 V, R_{C} = 1 kΩ, R_{b} = 100 kΩ and β = 100 . Value of base current I_{b} is$ (1) $I_{b} = 1.0 μA$ (2) $I_{b} = 0.1 μA$ (3) $I_{b} = 100 μA$ (4) $I_{b} = 10 μA$ 392. $What will be the input of A and B for the Boolean expression (A + B) \cdot (A \cdot B) = 1 [2015]$ (1) $0, 0$ (2) $0, 1$ (3) $1, 0$ (4) $1, 1$ 393. $Digital signal$ (1) $is represented by a sine wave$ (2) $utilizes binary code system$ (3) $is represented by a cosine wave$ (4) $utilizes a hexadecimal code$ 394. $A zener diode is made by$ (1) $heavily doping both p - and n -sides of a p - n junction diode$ (2) $heavily doping the p -side and lightly doping the n -side of a p - n junction diode$ (3) $lightly doping the p -side and heavily doping the n -side of a p - n junction diode$ (4) $lightly doping both p - and n -sides of a p - n junction diode$ 395. $When an n-type semiconductor is heated$ (1) $number of electrons increases while that of holes decreases$ (2) $number of holes increases while that of electrons decreases$ (3) $number of holes and electrons do not change$ (4) $number of holes and electrons increases equally$ 396. $The I - V characteristic of an LED is:$ (1) (2) (3) (4) 397. $In a p-n-p transistor$ (1) $emitter is heavily doped and collector is moderately doped.$ (2) $emitter is moderately doped and collector is heavily doped.$ (3) $both emitter and collector are heavily doped.$ (4) $both emitter and collector are moderately doped.$ 398. $In a p‐n junction [2002]$ (1) $p and n both are at same potential$ (2) $High potential at n side and low potential at p side$ (3) $High potential at p side and low potential at n side$ (4) $Low potential at n side and zero potential at p side$ 399. $The forward biased diode connection is$ (1) (2) (3) (4) 400. $Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity. Reason R: For a p-n junction diode, at applied voltage V the current in the forward bias is more than the current in the reverse bias for \| V_{Z} \| > \pm V > \| V_{0} \| where V_{0} is the threshold voltage and V_{z} is the breakdown voltage. In the light of the above statements, choose the correct answer from the options given below$ (1) $Both A and R are true and R is correct explanation A$ (2) $Both A and R are true but R is NOT the correct explanation A$ (3) $A is false but R is true$ (4) $A is true but R is false$ 401. $Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Diffusion current in a p - n junction is greater than the drift current in magnitude if the junction is forward biased. Reason R: Diffusion current in a p - n junction is form the n-side to the p-side if the junction is forward biased. In the light of the above statements, choose the most appropriate answer from the options given below.$ (1) $Both A and R are correct but R is NOT the correct explanation of A$ (2) $A is correct but R is not correct$ (3) $A is not correct but R is correct$ (4) $Both A and R is correct and R is the correct explanation of A$ 402. $The output of OR gate is 1 [2004]$ (1) $If both inputs are zero$ (2) $If either or both inputs are 1$ (3) $Only if both inputs are 1$ (4) $If either input is zero$ 403. $Zener diode is used for [2005]$ (1) $producing oscillations in an oscillator$ (2) $amplification$ (3) $stabilization$ (4) $rectification$ 404. $A positive hole in a semiconductor is$ (1) $absence of free electrons$ (2) $an artificially created particle$ (3) $an anti-particle of electron$ (4) $a vacancy created when an electron leaves a covalent bond.$ 405. $At absolute zero, Si acts as$ (1) $non-metal$ (2) $metal$ (3) $insulator$ (4) $none of these$ 406. $Statement I : When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons. Statement II : When such P-type and N-type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ammeter. In the light of above statements, choose the most appropriate answer from the options given below.$ (1) $Both Statement I and statement II are incorrect$ (2) $Statement I is incorrect but statement II is correct$ (3) $Both Statement I and statement II are correct$ (4) $Statement I is correct but statement II is incorrect$ 407. $The energy band gap is maximum in :$ (1) $metals$ (2) $superconductors$ (3) $insulators$ (4) $semiconductors$ 408. $Identify the incorrect statement.$ (1) $When a P-N junction diode is forward biased, the width of the depletion region decreases.$ (2) $When a P-N junction diode is reverse biased, the barrier potential increases.$ (3) $A photon diode is operated in the reverse bias.$ (4) $An LED is a lightly doped P-N junction diode which emits spontaneous radiation of forward biasing.$ 409. $In the combination of the following gates, the output Y can be written in terms of inputs A and B as [NEET 2018]$ (1) $A \cdot B + A \cdot B$ (2) $A \cdot B^{'} + A^{'} \cdot B$ (3) $A \cdot B$ (4) $A + B$ 410. $Choose the correct Boolean expression for the given circuit diagram:$ (1) $A \cdot B$ (2) $A + B$ (3) $A + B$ (4) $A \cdot B$ 411. $Which of the following statements is incorrect?$ (1) $The resistance of intrinsic semiconductors decrease with increase of temperature.$ (2) $Doping pure Si with trivalent impurities give p -type semiconductors.$ (3) $The majority carriers in n -type semiconductors are holes.$ (4) $A p - n junction can act as a semiconductor device$ 412. $Find VAB [2017]$ (1) $10 V$ (2) $20 V$ (3) $30 V$ (4) $None of these$ 413. $For an n-p-n transistor structure which of the following statements is NOT true?$ (1) $Emitter is heavily doped and moderate in size$ (2) $Base is lightly doped and thin in size$ (3) $Collector is lightly doped and large in size$ (4) $Collector is moderately doped and large in size$ 414. $The truth table given below corresponds to logic gate. A B X 000011101111$ (1) $NAND$ (2) $OR.$ (3) $AND$ (4) $XOR$ 415. $In a solar cell, current is generated due to bond breakage in which region? [2018]$ (1) $depletion region$ (2) $n ‐region$ (3) $p ‐region$ (4) $None of these$ 416. $The given truth table is for Input A 0011 B 0101 Output Y 1110$ (1) $OR gate$ (2) $NOR gate$ (3) $AND gate$ (4) $NAND gate$ 417. $Which of the following circuits is reverse - biased?$ (1) (2) (3) (4) 418. $The forbidden energy gap for ' G e^{’} crystal at O' K is$ (1) $2.57 eV$ (2) $0.071 eV$ (3) $6.57 eV$ (4) $0.71 eV$ 419. $With forward biased mode, the p - n junction diode$ (1) $is one in which width of depletion layer increases$ (2) $is one in which potential barrier increases$ (3) $acts as closed switch$ (4) $acts as open switch$ 420. $The energy of a photon in a monochromatic light of wavelength 621 nm matches with the band gap of a semiconducting material. Then the minimum energy required to create an electron-hole pair from the semiconductor is [Take hc = 1242 eV - nm, where h is Planck's constant and c is speed of light in vacuum]$ (1) $3.4 eV$ (2) $1.7 eV$ (3) $2 eV$ (4) $2.2 eV$