Electronics and Communication GATE 2024 Questions with Answer

Ques 14 Digital Circuits


A 4-bit priority encoder has inputs $D_3$, $D_2$, $D_1$, and $D_0$ in descending order of priority. The two-bit output $B_1 B_0$ is generated as 00, 01, 10, and 11 corresponding to $D_3$, $D_2$, $D_1$, and $D_0$, respectively.
The Boolean expression of the output bit $B_1$ is

A

$D_3 D_2$

B

$\overline{D_3} D_2 + \overline{D_3} \overline{D_1}$

C

$D_3 \overline{D_2} + \overline{D_3} D_1$

D

$\overline{D_3} \overline{D_1}$


Ques 15 Digital Circuits


The propagation delay of the 2×1 MUX shown in the circuit is 10 ns.
Consider the propagation delay of the inverter as 0 ns.

If S is set to 1 then the output Y is

A

a square wave of frequency 100 MHz

B

a square wave of frequency 50 MHz

C

constant at 0

D

constant at 1


Ques 16 Digital Circuits


The sequence of states $(Q_1 Q_0)$ of the given synchronous sequential circuit is

A

$00 → 10 → 11 → 00$

B

$11 → 00 → 10 → 01 → 00$

C

$01 → 10 → 11 → 00 → 01$

D

$00 → 01 → 10 → 00$


Ques 17 Electromagnetic Theory


Consider a lossless transmission line terminated with a short circuit as shown in the figure below.
As one moves towards the generator from the load, the normalized impedances $Z_{inA}$, $Z_{inB}$, $z_{inC}$, and $\mathcal{Z}_{inD}$ (indicated in the figure) are

A

$Z_{inA}=+1j~\Omega$, $z_{inB}=\infty$, $z_{inC}=-1j~\Omega$, $Z_{inD}=0$

B

$Z_{inA}=\infty$, $z_{inB}=+0.4j~S$, $Z_{inD}=+0.4j~\Omega$

C

$z_{inD}=\infty$

D

$Z_{inC}=-0.4j~\Omega$, $Z_{inD}=0$


Ques 18 Electromagnetic Theory


$\hat{i}$ and $\hat{j}$ be the unit vectors along x and y axes, respectively and let A be a positive constant.
Which one of the following statements is true for the vector fields $\overline{F_{1}}=A(\hat{i}y+\hat{j}x)$ and $\vec{F_{2}}=A(\hat{i}y-\hat{j}x)$?

A

Both $\vec{F_{1}}$ and $\vec{F_{2}}$ are electrostatic fields.

B

Only $\vec{F}_{1}$ is an electrostatic field.

C

Only $F_{2}$ is an electrostatic field.

D

Neither $\vec{F}_{1}$ nor $\vec{F_{2}}$ is an electrostatic field.


Ques 19 Electromagnetic Theory


A uniform plane wave with electric field $E⃗(x)=A_y â_y e^{-j\frac{2πx}{3}} V/m$ is travelling in the air (relative permittivity, $ε_r=1$ and relative permeability, $μ_r=1$) in the +x direction ($A_y$ is a positive constant, $â_y$ is the unit vector along the y-axis). It is incident normally on an ideal electric conductor (conductivity, σ=∞) at x=0.
The position of the first null of the total magnetic field in the air (measured from x=0, in metres) is

A

$-\frac{3}{4}$

B

$-\frac{3}{2}$

C

-6

D

-3


Ques 20 Electromagnetic Theory


A lossless transmission line with characteristic impedance $Z_0 = 50 Ω$ is terminated with an unknown load.
The magnitude of the reflection co-efficient is $|Γ| = 0.6$.
As one moves towards the generator from the load, the maximum value of the input impedance magnitude looking towards the load (in Ω) is

125 is the correct answer.


Ques 21 Electronic Devices and Circuits


In the circuit below, assume that the long channel NMOS transistor is biased in saturation.
The small signal trans-conductance of the transistor is $g_{m}$. Neglect body effect, channel length modulation and intrinsic device capacitances.
The small signal input impedance $Z_{in}(j\omega)$ is

A

$\frac{-g_{m}}{C_{1}C_{L}\omega^{2}}+\frac{1}{j\omega C_{1}}+\frac{1}{j\omega C_{L}}$

B

$\frac{g_{m}}{C_{1}C_{L}\omega^{2}}+\frac{1}{j\omega C_{1}}+\frac{1}{j\omega C_{L}}$

C

$\frac{1}{j\omega C_{1}}+\frac{1}{j\omega C_{L}}$

D

$\frac{-g_{m}}{C_{1}C_{L}\omega^{2}}+\frac{1}{j\omega C_{1}+j\omega C_{L}}$


Ques 22 Electronic Devices and Circuits


For the closed loop amplifier circuit shown below, the magnitude of open loop low frequency small signal voltage gain is 40. All the transistors are biased in saturation.
The current source $I_{SS}$ is ideal. Neglect body effect, channel length modulation and intrinsic device capacitances.
The closed loop low frequency small signal voltage gain $\frac{v_{out}}{v_{in}}$ (rounded off to three decimal places) is

A

0.976

B

1.000

C

1.025

D

0.488


Ques 23 Electronic Devices and Circuits


For non-degenerately doped n-type silicon, which one of the following plots represents the temperature (T) dependence of free electron concentration (n)?

A

B

C

D


Ques 24 Electronic Devices and Circuits


In the circuit shown, the n: 1 step-down transformer and the diodes are ideal.
The diodes have no voltage drop in forward biased condition.
If the input voltage (in Volts) is $V_{s}(t)=10sinωt$ and the average value of load voltage $V_{L}(t)$ (in Volts) is $2.5/π$, the value of n is

A

4

B

8

C

12

D

16


Ques 25 Electronic Devices and Circuits


The free electron concentration profile n(x) in a doped semiconductor at equilibrium is shown in the figure, where the points A, B, and C mark three different positions.
Which of the following statements is/are true?

A

For x between B and C, the electron diffusion current is directed from C to B.

B

For x between B and A, the electron drift current is directed from B to A.

C

For x between B and C, the electric field is directed from B to C.

D

For x between B and A, the electric field is directed from A to B.


Ques 26 Electronic Devices and Circuits


In the given circuit, the current Ix (in mA) is _____________.

3 is the correct answer.


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