GATE ECE format:mcq PYQs & Answers — Page 19

Questions 181–190 of 426. Imported answers require independent review unless marked reviewed.

Consider a long rectangular bar of direct bandgap

-type semiconductor. The equilibrium hole density is

and the intrinsic carrier concentration is

. Electron and hole diffusion lengths are

and

, respectively.

The left side of the bar (

) is uniformly illuminated with a laser having photon energy greater than the bandgap of the semiconductor. Excess electron-hole pairs are generated ONLY at

because of the laser. The steady state electron density at

due to laser illumination. Under these conditions and ignoring electric field, the closest approximation (among the given options) of the steady state electron density at

is _________.

Your answerChoose one option.

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In a non-degenerate bulk semiconductor with electron density

, the value of

, where

and

denote the bottom of the conduction band energy and electron Fermi level energy, respectively. Assume thermal voltage as

and the intrinsic carrier concentration is

. For

, the closest approximation of the value of

, among the given options, is _________.

Your answerChoose one option.

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Consider the CMOS circuit shown in the figure (substrates are connected to their respective sources). The gate width (

) to gate length (

) ratios (

) of the transistors are as shown. Both the transistors have the same gate oxide capacitance per unit area. For the

MOSFET, the threshold voltage is

and the mobility of holes is

. For the

MOSFET, the threshold voltage is

and the mobility of electrons is

. The steady state output voltage

is _________.

Diagram for Electronics and Communication Engineering question 18

Your answerChoose one option.

equal to 0 V

more than 2 V

less than 2 V

equal to 2 V

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Consider the 2-bit multiplexer (MUX) shown in the figure. For OUTPUT to be the XOR of C and D, the values for

, and

are ____________.

Diagram for Electronics and Communication Engineering question 19

Your answerChoose one option.

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The ideal long channel

MOSFET and

MOSFET devices shown in the circuits have threshold voltages of 1 V and

V, respectively. The MOSFET substrates are connected to their respective sources. Ignore leakage currents and assume that the capacitors are initially discharged. For the applied voltages as shown, the steady state voltages are ________________.

Diagram for Electronics and Communication Engineering question 20

Your answerChoose one option.

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Consider a closed-loop control system with unity negative feedback and

in the forward path, where the gain

. The complete Nyquist plot of the transfer function

is shown in the figure. Note that the Nyquist contour has been chosen to have the clockwise sense. Assume

has no poles on the closed right-half of the complex plane. The number of poles of the closed-loop transfer function in the closed right-half of the complex plane is ____________.

Diagram for Electronics and Communication Engineering question 21

Your answerChoose one option.

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The root-locus plot of a closed-loop system with unity negative feedback and transfer function

in the forward path is shown in the figure. Note that

is varied from 0 to

Select the transfer function

that results in the root-locus plot of the closed-loop system as shown in the figure.

Diagram for Electronics and Communication Engineering question 22

Your answerChoose one option.

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The frequency response

of a linear time-invariant system has magnitude as shown in the figure.

Statement I: The system is necessarily a pure delay system for inputs which are bandlimited to

Statement II: For any wide-sense stationary input process with power spectral density

, the output power spectral density

obeys

for

Which one of the following combinations is true?

Diagram for Electronics and Communication Engineering question 23

Your answerChoose one option.

Statement I is correct, Statement II is correct

Statement I is correct, Statement II is incorrect

Statement I is incorrect, Statement II is correct

Statement I is incorrect, Statement II is incorrect

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In a circuit, there is a series connection of an ideal resistor and an ideal capacitor. The conduction current (in Amperes) through the resistor is

. The displacement current (in Amperes) through the capacitor is ________.

Your answerChoose one option.

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The function

attains its minimum over the interval

________. (Here

is the natural logarithm of

Your answerChoose one option.

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GATE ECE format:mcq PYQs

Question 16

Question 17

Question 18

Question 19

Question 20

Question 21

Question 22

Question 23

Question 24

Question 36