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TIFR ECE 2023 | Question: 15
Let $\left\{x_{n}\right\}_{n \geq 0}$ be a sequence of real numbers which satisfy \[ x_{n+1}\left(1+x_{n+1}\right) \leq x_{n}\left(1+x_{n}\right), \quad n \geq 0 . \] Choose the correct option from the ... is always bounded but does not necessarily converge. The sequence always converges to a non-zero limit. The sequence always converges to zero. None of the above.

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 14
Suppose that $Z \sim \mathcal{N}(0,1)$ is a Gaussian random variable with mean zero and variance $1$. Let $F(z) \equiv \mathbb{P}(Z \leq z)$ be the cumulative distribution function $\operatorname{(CDF)}$ of $Z$. Define a new random variable $Y$ as $Y=F(Z)$. This means that the ... of $\mathbb{E}[Y]$ is: $F(1)$ $1$ $\frac{1}{2}$ $\frac{1}{\sqrt{2 \pi}}$ $\frac{\pi}{4}$

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 13
Let $X$ be a random variable which takes values $1$ and $-1$ with probability $1 / 2$ each. Suppose $Y=X+N$, where $N$ is a random variable independent of $X$ with the following probability density function (p.d.f.): \[ f_{N}(n)=\left\{\begin{array} ... $0$ $1 / 8$ $1 / 4$ $1 / 2$ None of the above

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 12
Consider a disk $D$ of radius 1 centered at the origin. Let $X$ be a point uniformly distributed on $D$ and let the distance of $X$ from the origin be $R$. Let $A$ be the (random) area of the disk with radius $R$ centered at the origin. Then $\mathbb{E}[A]$ is $\frac{\pi}{3}$ $\frac{\pi}{6}$ $\frac{\pi}{4}$ $\frac{\pi}{2}$ None of the above

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 11
Consider the function \[ f(x)=x e^{|x|}+4 x^{2} \] for values of $x$ which lie in the interval $[-1,1]$. In this domain, suppose the function attains the minimum value at $x^{*}$. Which of the following is true? $-1 \leq x^{*}<-0.5$ $-0.5 \leq x^{*}<0$ $x^{*}=0$ $0<x^* \leq 0.5$ $0.5<x^* \leq 1$

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 10
Convolution between two functions $f(t)$ and $g(t)$ is defined as follows: \[ f(t) * g(t)=\int_{-\infty}^{\infty} f(\tau) g(t-\tau) d \tau \] Let $u(t)$ be the unit-step function, i.e., $u(t)=1$ for $t \geq 0$ and $u(t)=0$ for $t<0$. What is $f(t) * g(t)$ ... $\frac{1}{2}(\exp (-t)+\sin (t)-2 \cos (t)) u(t)$ $\frac{1}{2}(\exp (-t)-\sin (t)+2 \cos (t)) u(t)$

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 9
Consider an $n \times n$ matrix $A$ with the property that each element of $A$ is non-negative and the sum of elements of each row is $1$ . Consider the following statements. 1. $1$ is an eigenvalue of $A$ 2. The magnitude of any eigenvalue of $A$ ... statements $1$ and $3$ are correct Only statements $2$ and $3$ are correct All statements $1,2$ , and $3$ are correct

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 8
Suppose a bag contains 5 red balls, 3 blue balls, and 2 black balls. Balls are drawn without replacement until the bag is empty. Let $X_{i}$ be a random variable which takes value 1 if the $i$-th ball drawn is red, value 2 if that ball is blue, and 3 if it is black. Let the ... Only (i) and (ii) Only (i) and (iii) All of (i), (ii), and (iii) None of (i), (ii), or (iii)

makhdoom ghaya edited in Others Mar 20

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TIFR ECE 2023 | Question: 7
Let $f(x)$ be a positive continuous function on the real line that is the density of a random variable $X$. The differential entropy of $X$ is defined to be $-\int_{-\infty}^{\infty} f(x) \ln f(x) d x$. In which case does $X$ have the least differential entropy? You may use these facts: The ... $f(x):=(1 / 4) e^{-|x| / 2}$. $f(x):=e^{-2|x|}$.

makhdoom ghaya edited in Others Mar 19

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TIFR ECE 2023 | Question: 2
$\begin{array}{rlr}a^*=\max _{x, y} & x^2+y^2-8 x+7 \\ \text { s.t. } & x^2+y^2 \leq 1 \\ & y \geq 0\end{array}$ Then $a^{\star}$ is $16$ $14$ $12$ $10$ None of the above

makhdoom ghaya edited in Others Mar 19

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TIFR ECE 2023 | Question: 6
An ant in the plane travels in a spiral such that its position $(x(t), y(t))$ at time $t \geq 0$ is $\left(e^{t} \cos t, e^{t} \sin t\right)$. At time $t=1$, find the real part of $\ln (x(t)+i y(t))$. $-2$ $1$ $0$ $-1$ $2$

makhdoom ghaya edited in Others Mar 18

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TIFR ECE 2023 | Question: 5
Let $\mathrm{B}$ denote the unit ball in $\mathbb{R}^{2}$, and $\mathrm{Q}$ a square of side length $2$. Let $\mathrm{K}$ be the set of all vectors $z$ such that for some $x \in \mathrm{B}$ and some $y \in \mathrm{Q}, z=x+y$. The area of $\mathrm{K}$ is $4+\pi$ $6+\pi$ $8+\pi$ $10+\pi$ $12+\pi$

makhdoom ghaya edited in Others Mar 18

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TIFR ECE 2023 | Question: 4
Recall that the entropy (in bits) of a random variable $\mathrm{X}$ which takes values in $\mathbb{N}$ ... random variable which denotes the number of tosses made. What is the entropy of $\mathrm{X}$ in bits? $1$ $2$ $4$ Infinity None of the above

makhdoom ghaya edited in Others Mar 18

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TIFR ECE 2023 | Question: 3
Let \[ \mathcal{P}=\left\{(x, y): x+y \geq 1,2 x+y \geq 2, x+2 y \geq 2,(x-1)^{2}+(y-1)^{2} \leq 1\right\} . \] Compute \[ \min _{(x, y) \in \mathcal{P}} 2 x+3 y \] $2$ $3$ $4$ $6$ None of the above

makhdoom ghaya edited in Others Mar 18

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TIFR ECE 2023 | Question: 1
Consider a fair coin with probability of heads and tails equal to $1 / 2$. Moreover consider two dice, first $\mathrm{D}_{1}$ that has three faces numbered $1,3,5$ and second $\mathrm{D}_{2}$ that has three faces numbered $2,4,6$ ... rolled dice in the experiment. What is $\mathbb{E}[X]$ ? $\frac{7}{2}$ 4 3 $\frac{9}{2}$ None of the above

makhdoom ghaya edited in Others Mar 18

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GATE ECE 2020 | Question: 18
In the circuit shown below, all the components are ideal. If $V_{i}$ is $+2\:V$, the current $I_{o}$ sourced by the op-amp is __________ $\text{mA}$.

shanmukh2099 answered in Analog Circuits Mar 9

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GATE ECE 2006 | Question: 35
Consider two transfer functions $ \mathrm{G}_1(s)=\frac{1}{s^2+a s+b} \text { and } \mathrm{G}_2(s)=\frac{s}{s^2+a s+b} $ The $3\text{-dB}$ bandwidths of their frequency responses are, respectively $\sqrt{a^2-4 b}, \sqrt{a^2+4 b}$ $\sqrt{a^2+4 b}, \sqrt{a^2-4 b}$ $\sqrt{a^2-4 b}, \sqrt{a^2-4 b}$ $\sqrt{a^2+4 b}, \sqrt{a^2+4 b}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 34
In the figure shown, assume that all the capacitors are initially uncharged. If $\text{V}_i(t)=10 u(t)$ Volts, then $\text{V}_0(t)$ is given by $8 e^{-0.004 t}$ Volts $8\left(1-e^{-0.004 t}\right)$ Volts $8 u(t)$ Volts $8$ Volts

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 33
A $2 \; \mathrm{mH}$ inductor with some initial current can be represented as shown below, where $s$ is the Laplace Transform variable. The value of initial current is $0.5 \mathrm{~A}$ $2.0 \mathrm{~A}$ $1.0 \mathrm{~A}$ $0.0 \mathrm{~A}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 32
The first and the last critical frequencies (singularities) of a driving point impedance function of a passive network having two kinds of elements, are a pole and a zero respectively. The above property will be satisfied by $\text{RL}$ network only $\text{RC}$ network only $\text{LC}$ network only $\mathrm{RC}$ as well as $\mathrm{RL}$ networks

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 31
In the two port network shown in the figure below, $z_{12}$ and $z_{21}$ are, respectively $r_e$ and $\beta r_o$ $0$ and $-\beta r_o$ $0,$ and $\beta r_o$ $r_e$ and $-\beta r_o$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 30
A two-port network is represented by $\text{ABCD}$ ... $\frac{\mathrm{B}+\mathrm{AR}_{\mathrm{L}}}{\mathrm{D}+\mathrm{CR}_{\mathrm{L}}}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 29
As $x$ is increased from $-\infty$ to $\infty$, the function $ f(x)=\frac{e^x}{1+e^x} $ monotonically increases monotonically decreases increases to a maximum value and then decreases decreases to a minimum value and then increases

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 28
Consider the function $f(t)$ having Laplace transform $ \text{F}(s)=\frac{\omega_0}{s^2+\omega_0^2} \operatorname{Re}[s]>0 $ The final value of $f(t)$ would be $0$ $1$ $-1 \leq f(\infty) \leq 1$ $\infty$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 27
For the differential equation $\dfrac{d^2 y}{d x^2}+k^2 y=0$, the boundary conditions are $y=0$ for $x=0$, and $y=0$ for $x=a$ The form of non-zero solutions of $y$ (where $m$ ... $y=\displaystyle{}\sum_m\;\mathrm{~A}_{m} \;e^{-\frac{m \pi x}{a}}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 26
For the matrix $\left[\begin{array}{ll}4 & 2 \\ 2 & 4\end{array}\right]$, the eigen value corresponding to the eigenvector $\left[\begin{array}{l}101 \\ 101\end{array}\right]$ is $2$ $4$ $6$ $8$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 25
Three companies $\text{X, Y}$ and $\text{Z}$ ... computer is defective, the probability that it was supplied by $\text{Y}$ is $0.1$ $0.2$ $0.3$ $0.4$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 24
The integral $\displaystyle{}\int_0^\pi \sin ^3 \theta\; d \theta$ is given by $\frac{1}{2}$ $\frac{2}{3}$ $\frac{4}{3}$ $\frac{8}{3}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 23
The value of the contour integral $\displaystyle{}\oint_{\mid z-j \mid =2} \;\frac{1}{z^2+4} d z$ in positive sense is $\frac{j \pi}{2}$ $-\frac{\pi}{2}$ $-\frac{j \pi}{2}$ $\frac{\pi}{2}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 22
For the function of a complex variable $\text{W}=\ln \text{Z}\; ($where, $\mathrm{W}=u+j \mathrm{v}$ and $\mathrm{Z}=x+j y),$ the $u=$ constant lines get mapped in $\text{Z}$-plane as set of radial straight lines set of concentric circles set of confocal hyperbolas set of confocal ellipses

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 21
The eigenvalues and the corresponding eigen vectors of a $2 \times 2$ ... $\left[\begin{array}{ll}4 & 8 \\ 8 & 4\end{array}\right]$

Lakshman Patel RJIT edited in Others Feb 25

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32

GATE ECE 2006 | Question: 20
A transmission line is feeding $1 \mathrm{Watt}$ of power to a horn antenna having a gain of $10 \mathrm{~dB}$. The antenna is matched to the transmission line. The total power radiated by the horn antenna into the free-space is $10$ Watts $1$ Watt $0.1$ Watt $0.01$ Watt

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 19
The electric field of an electomagnetic wave propagating in the positive $z$-direction is given by $ \left.\text{E}=\hat{a_x} \sin (\omega t-\beta z\right)+\hat{a_y} \sin \left(\omega t-\beta z+\frac{\pi}{2}\right) $ The wave is linearly polarized in the $z$-direction elliptically polarized left-hand circularly polarized right-hand circularly polarized

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 18
In the system shown below, $x(t)=(\sin t) u(t)$. In steady-steady-state, the response $y(t)$ will be $\frac{1}{\sqrt{2}} \sin \left(t-\frac{\pi}{4}\right)$ $\frac{1}{\sqrt{2}} \sin \left(t+\frac{\pi}{4}\right)$ $\frac{1}{\sqrt{2}} e^{-t} \sin t$ $\sin t-\cos t$

Lakshman Patel RJIT edited in Others Feb 25

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35

GATE ECE 2006 | Question: 17
The open-loop transfer function of a unity-gain feedback control system is given by $ \text{G}(s)=\frac{\text{K}}{(s+1)(s+2)} $ The gain margin of the system in $\text{dB}$ is given by $0$ $1$ $20$ $\infty $

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 16
If the region of convergence of $x_1[n]+x_2[n]$ is $\frac{1}{3}<|z|<\frac{2}{3}$, then the region of convergence of $x_1[n]-x_2[n]$ includes $\frac{1}{3}<|z|<3$ $\frac{2}{3}<|z|<3$ $\frac{2}{3}<|z|<3$ $\frac{1}{3}<|z|<\frac{2}{3}$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 15
The Dirac delta function $\delta(t)$ is defined as $\delta(t)= \begin{cases}1, & t=0 \\ 0, & \text { otherwise }\end{cases}$ $\delta(t)= \begin{cases}\infty, & t=0 \\ 0, & \text { otherwise }\end{cases}$ ... $\displaystyle{}\int_{-\infty}^\infty \delta(t) d t=1$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 14
Let $x(t) \longleftrightarrow \mathrm{X}(j \omega)$ be Fourier Transform pair. The Fourier Transform of the signal $x(5 t-3)$ in terms of $X(j \omega)$ is given as $\frac{1}{5} e^ - \frac{j 3\omega }{5} \times\left(\frac{j \omega}{5}\right)$ ... $\frac{1}{5} e^{j 3 \omega} \times\left(\frac{j \omega}{5}\right)$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 13
The number of product terms in the minimized sum-of-product expression obtained through the following $\text{K}$-map is (where, " $d$ ... $2$ $3$ $4$ $5$

Lakshman Patel RJIT edited in Others Feb 25

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GATE ECE 2006 | Question: 12
An $n$-channel depletion MOSFET has following two points on its $\mathrm{I}_\text{D}-\mathrm{V}_{\text {GS}}$ curve $\text{V}_{\text{Gs}}=0$ at $\text{I}_\text{D}=12 \mathrm{~mA}$ and $\mathrm{V}_{\mathrm{GS}}=-6$ Volts at $\mathrm{I}_{\mathrm{D}}=0$ Which ... $\text{V}_{\text {Gs }}=0 \; \text{Volts}$ $\mathrm{V}_{\mathrm{Gs}}=3 \; \text{Volts}$

Lakshman Patel RJIT edited in Others Feb 25

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