A simplified small-signal equivalent circuit of a BJT-based amplifier is given below. The small-signal voltage gain $V_o / V_s$ (in $\mathrm{V} / \mathrm{V}$ ) is_________.

The identical MOSFETs $M_1$ and $M_2$ in the circuit given below are ideal and biased in the saturation region. $M_1$ and $M_2$ have a transconductance $g_m$ of 5 mS .

The input signals (in Volts) are:

$$ \begin{aligned} & V_1=2.5+0.01 \sin \omega t \\ & V_2=2.5-0.01 \sin \omega t \end{aligned} $$

The output signal $V_3$ (in Volts) is _ .

All the diodes in the circuit given below are ideal.

Which of the following plots is/are correct when $V_I$ (in Volts) is swept from $-M$ to $M$ ?

The diode in the circuit shown below is ideal. The input voltage (in Volts) is given by $V_1=10 \sin 100 \pi t$, where time $t$ is in seconds.

The time duration (in ms, rounded off to two decimal places) for which the diode is forward biased during one period of the input is ________.

Consider a frequency-modulated (FM) signal

$$ f(t)=A_c \cos \left(2 \pi f_c t+3 \sin \left(2 \pi f_1 t\right)+4 \sin \left(6 \pi f_1 t\right)\right) $$

where $A_c$ and $f_c$ are, respectively, the amplitude and frequency (in Hz ) of the carrier waveform. The frequency $f_1$ is in Hz , and assume that $f_c>100 f_1$.

The peak frequency deviation of the FM signal in Hz is $\qquad$

Consider an additive white Gaussian noise (AWGN) channel with bandwidth $W$ and noise power spectral density $\frac{N_o}{2}$. Let $P_{a v}$ denote the average transmit power constraint. Which one of the following plots illustrates the dependence of the channel capacity $C$ on the bandwidth $W$ (keeping $P_{a v}$ and $N_0$ fixed)?

Consider a message signal $m(t)$ which is bandlimited to $[-W, W]$, where $W$ is in Hz . Consider the following two modulation schemes for the message signal:

Double sideband-suppressed carrier (DSB-SC):

$$ f_{\mathrm{DSB}}(t)=A_c m(t) \cos \left(2 \pi f_c t\right) $$

Amplitude modulation (AM):

$$ f_{\mathrm{AM}}(t)=A_c(1+\mu m(t)) \cos \left(2 \pi f_c t\right) $$

Here, $A_c$ and $f_c$ are the amplitude and frequency (in Hz ) of the carrier, respectively. In the case of AM, $\mu$ denotes the modulation index.

Consider the following statements:

(i) An envelope detector can be used for demodulation in the DSB-SC scheme if $m(t)>0$ for all $t$.

(ii) An envelope detector can be used for demodulation in the AM scheme only if $m(t)>0$ for all $t$.

Which of the following options is/are correct?

The generator matrix of a $(6,3)$ binary linear block code is given by

$$ G=\left[\begin{array}{llllll} 1 & 0 & 0 & 1 & 0 & 1 \\ 0 & 1 & 0 & 0 & 1 & 1 \\ 0 & 0 & 1 & 1 & 1 & 0 \end{array}\right] $$

The minimum Hamming distance $d_{\min }$ between codewords equals___________ (answer in integer).

A source transmits symbol $S$ that takes values uniformly at random from the set $\{-2,0,2\}$. The receiver obtains $Y=S+N$, where $N$ is a zero-mean Gaussian random variable independent of $S$. The receiver uses the maximum likelihood decoder to estimate the transmitted symbol $S$.

Suppose the probability of symbol estimation error $P_e$ is expressed as follows:

$$ P_e=\alpha P(N>1), $$

where $P(N>1)$ denotes the probability that $N$ exceeds 1 .

What is the value of $\alpha$ ?

Consider a real-valued random process

$$ f(t)=\sum\limits_{n=1}^N a_n p(t-n T), $$

where $T>0$ and $N$ is a positive integer. Here, $p(t)=1$ for $t \in[0,0.5 T]$ and 0 otherwise. The coefficients $a_n$ are pairwise independent, zero-mean unit-variance random variables. Read the following statements about the random process and choose the correct option.

(i) The mean of the process $f(t)$ is independent of time $t$.

(ii) The autocorrelation function $E[f(t) f(t+\tau)]$ is independent of time $t$ for all $\tau$. (Here, $E[\cdot]$ is the expectation operation.)

The random variable $X$ takes values in $\{-1,0,1\}$ with probabilities $P(X=-1)=P(X=1)$ and $\alpha$ and $P(X=0)=1-2 \alpha$, where $0<\alpha<\frac{1}{2}$.

Let $g(\alpha)$ denote the entropy of $X$ (in bits), parameterized by $\alpha$. Which of the following statements is/are TRUE?

$X$ and $Y$ are Bernoulli random variables taking values in $\{0,1\}$. The joint probability mass function of the random variables is given by:

$$ \begin{aligned} & P(X=0, Y=0)=0.06 \\ & P(X=0, Y=1)=0.14 \\ & P(X=1, Y=0)=0.24 \\ & P(X=1, Y=1)=0.56 \end{aligned} $$

The mutual information $I(X ; Y)$ is ___________(rounded off to two decimal places).

The Nyquist plot of a system is given in the figure below. Let $\omega_{\mathrm{P}}, \omega_Q, \omega_R$, and $\omega_{\mathrm{S}}$ be the positive frequencies at the points $P, Q, R$, and $S$, respectively. Which one of the following statements is TRUE?

Consider the unity-negative-feedback system shown in Figure (i) below, where gain $K \geq 0$. The root locus of this system is shown in Figure (ii) below. For what value(s) of $K$ will the system in Figure (i) have a pole at $-1+j 1$ ?

Let $G(s)=\frac{1}{10 s^2}$ be the transfer function of a second-order system. A controller $M(s)$ is connected to the system $G(s)$ in the configuration shown below. Consider the following statements.

(i) There exists no controller of the form $M(s)=\frac{K_I}{s}$, where $K_I$ is a positive real number, such that the closed loop system is stable.

(ii) There exists at least one controller of the form $M(s)=K_P+s K_D$, where $K_P$ and $K_D$ are positive real numbers, such that the closed loop system is stable.

Which one of the following options is correct?

Consider a system where $x_1(t), x_2(t)$, and $x_3(t)$ are three internal state signals and $u(t)$ is the input signal. The differential equations governing the system are given by

$$ \frac{d}{d t}\left[\begin{array}{l} x_1(t) \\ x_2(t) \\ x_3(t) \end{array}\right]=\left[\begin{array}{ccc} 2 & 0 & 0 \\ 0 & -2 & 0 \\ 0 & 0 & 0 \end{array}\right]\left[\begin{array}{l} x_1(t) \\ x_2(t) \\ x_3(t) \end{array}\right]+\left[\begin{array}{l} 1 \\ 1 \\ 1 \end{array}\right] u(t) $$

Which of the following statements is/are TRUE?

Consider a system represented by the block diagram shown below. Which of the following signal flow graphs represent(s) this system? Choose the correct option(s).

A full adder and an XOR gate are used to design a digital circuit with inputs $X, Y$, and $Z$, and output $F$, as shown below. The input $Z$ is connected to the carry-in input of the full adder.

If the input $Z$ is set to logic ' 1 ', then the circuit functions as __________ with $X$ and $Y$ as inputs.

A positive-edge-triggered sequential circuit is shown below. There are no timing violations in the circuit. Input $P 0$ is set to logic ' 0 ' and $P 1$ is set to logic ' 1 ' at all times. The timing diagram of the inputs SEL and $S$ are also shown below.

The sequence of output $Y$ from time $T_0$ to $T_3$ is $\qquad$ .

In the circuit shown below, the AND gate has a propagation delay of 1 ns . The edgetriggered flip-flops have a set-up time of 2 ns , a hold-time of 0 ns , and a clock-to-Q delay of 2 ns .

The maximum clock frequency (in MHz , rounded off to the nearest integer) such that there are no setup violations is___________ .

Which of the following can be used as an n-type dopant for silicon?

Select the correct option(s).

The electron mobility $\mu_n$ in a non-degenerate germanium semiconductor at 300 K is $0.38 \mathrm{~m}^2 / \mathrm{Vs}$.

The electron diffusivity $D_n$ at 300 K (in $\mathrm{cm}^2 / \mathrm{s}$, rounded off to the nearest integer) is ____________

(Consider the Boltzmann constant $k_B=1.38 \times 10^{-23} \mathrm{~J} / \mathrm{K}$ and the charge of an electron $e=1.6 \times 10^{-19} \mathrm{C}$.)

Consider the matrix $A$ below:

$$ A=\left[\begin{array}{llll} 2 & 3 & 4 & 5 \\ 0 & 6 & 7 & 8 \\ 0 & 0 & \alpha & \beta \\ 0 & 0 & 0 & \gamma \end{array}\right] $$

For which of the following combinations of $\alpha, \beta$ and $\gamma$, is the rank of $A$ at least three?

(i) $\alpha=0$ and $\beta=\gamma \neq 0$

(ii) $\alpha=\beta=\gamma=0$

(iii) $\beta=\gamma=0$ and $\alpha \neq 0$

(iv) $\alpha=\beta=\gamma \neq 0$

Consider the following series:

(i) $\sum\limits_{n=1}^{\infty} \frac{1}{\sqrt{n}}$

(ii) $ \sum\limits_{n=1}^{\infty} \frac{1}{n(n+1)}$

(iii) $\sum\limits_{n=1}^{\infty} \frac{1}{n!}$

A pot contains two red balls and two blue balls. Two balls are drawn from this pot randomly without replacement.

What is the probability that the two balls drawn have different colours?

Consider the function $f: \mathbb{R} \rightarrow \mathbb{R}$ defined as

$$ f(x)=2 x^3-3 x^2-12 x+1 $$

Which of the following statements is/are correct?

(Here, $\mathbb{R}$ is the set of real numbers.)

The function $y(t)$ satisfies

$$ t^2 y^{\prime \prime}(t)-2 t y^{\prime}(t)+2 y(t)=0 $$

where $y^{\prime}(t)$ and $y^{\prime \prime}(t)$ denote the first and second derivatives of $y(t)$, respectively. Given $y^{\prime}(0)=1$ and $y^{\prime}(1)=-1$, the maximum value of $y(t)$ over $[0,1]$ is ___________ (rounded off to two decimal places).

Consider a non-negative function $f(x)$ which is continuous and bounded over the interval $[2,8]$. Let $M$ and $m$ denote, respectively, the maximum and the minimum values of $f(x)$ over the interval.

Among the combinations of $\alpha$ and $\beta$ given below, choose the one(s) for which the inequality

$$ \beta \leq \int_2^8 f(x) d x \leq \alpha $$

is guaranteed to hold.

Which of the following statements involving contour integrals (evaluated counter-clockwise) on the unit circle $C$ in the complex plane is/are TRUE?

Consider the vectors

$$ a=\left[\begin{array}{l} 1 \\ 1 \end{array}\right], b=\left[\begin{array}{c} 0 \\ 3 \sqrt{2} \end{array}\right] $$

For real-valued scalar variable $x$, the value of

$$ \min _x\|a x-b\|_2 $$

is___________(rounded off to two decimal places).

$\|\cdot\|_2$ denotes the Euclidean norm, i.e., for $y=\left[\begin{array}{l}y_1 \\ y_2\end{array}\right],\|y\|_2=\sqrt{y_1^2+y_2^2}$.

Consider a part of an electrical network as shown below. Some node voltages, and the current flowing through the $3 \Omega$ resistor are as indicated.

The voltage (in Volts) at node $X$ is __________ .

Let $i_C, i_L$, and $i_R$ be the currents flowing through the capacitor, inductor, and resistor, respectively, in the circuit given below. The AC admittances are given in Siemens(S). Which one of the following is true?

In the circuit below, $M_1$ is an ideal AC voltmeter and $M_2$ is an ideal AC ammeter. The source voltage (in Volts) is $v_s(t)=100 \cos (200 t)$.

What should be the value of the variable capacitor $C$ such that the RMS readings on $M_1$ and $M_2$ are 25 V and 5 A , respectively?

The $Z$-parameter matrix of a two port network relates the port voltages and port currents as follows:

$$ \left[\begin{array}{l} V_1 \\ V_2 \end{array}\right]=Z\left[\begin{array}{l} I_1 \\ I_2 \end{array}\right] $$

The Z-parameter matrix (with each entry in Ohms) of the network shown below is

___________.

Consider the discrete-time system below with input $x[n]$ and output $y[n]$. In the figure, $h_1[n]$ and $h_2[n]$ denote the impulse responses of LTI Subsystems 1 and 2, respectively. Also, $\delta[n]$ is the unit impulse, and $b>0$.

Assuming $h_2[n] \neq \delta[n]$, the overall system (denoted by the dashed box) is_________.

Consider a continuous-time, real-valued signal $f(t)$ whose Fourier transform $F(\omega)=$$\mathop f\limits_{ - \infty }^\infty $$ f(t) \exp (-j \omega t) d t$ exists.

Which one of the following statements is always TRUE?

Consider a continuous-time finite-energy signal $f(t)$ whose Fourier transform vanishes outside the frequency interval $\left[-\omega_c, \omega_c\right]$, where $\omega_c$ is in rad/sec.

The signal $f(t)$ is uniformly sampled to obtain $y(t)=f(t) p(t)$. Here

$$ p(t)=\sum_{n=-\infty}^{\infty} \delta\left(t-\tau-n T_s\right) $$

with $\delta(t)$ being the Dirac impulse, $T_s>0$, and $\tau>0$. The sampled signal $y(t)$ is passed through an ideal lowpass filter $h(t)=\omega_c T_s \frac{\sin \left(\omega_c t\right)}{\pi \omega_c t}$ with cutoff frequency $\omega_c$ and passband gain $T_s$.

The output of the filter is given by $\qquad$ .

Let $f(t)$ be a periodic signal with fundamental period $T_0>0$. Consider the signal $y(t)=f(\alpha t)$, where $\alpha>1$.

The Fourier series expansions of $f(t)$ and $y(t)$ are given by

$$ f(t)=\sum\limits_{k = - \infty }^\infty c_k e^{j \frac{2 \pi}{T_0} k T} \text { and } y(t)=\sum\limits_{k = - \infty }^\infty d_k e^{j \frac{2 \pi}{T_0} \alpha k T} . $$

Which of the following statements is/are TRUE?

Here are two analogous groups, Group-I and Group-II, that list words in their decreasing order of intensity. Identify the missing word in Group-II.

Group-I: Abuse $\rightarrow$ Insult $\rightarrow$ Ridicule

Group-II: __________$\rightarrow$ Praise $\rightarrow$ Appreciate

The 12 musical notes are given as $C, C^{\#}, D, D^{\#}, E, F, F^{\#}, G, G^{\#}, A, A^{\#}$. Frequency of each note is $\sqrt[12]{2}$ times the frequency of the previous note. If the frequency of the note $C$ is 130.8 Hz , then the ratio of frequencies of notes $F^{\#}$ and $C$ is:

The following figures show three curves generated using an iterative algorithm. The total length of the curve generated after 'Iteration $n$ ' is:

Note: The figures shown are representative.

Which one of the following plots represents $f(x)=-\frac{|x|}{x}$, where $x$ is a non-zero real number?

Note: The figures shown are representative.

Identify the option that has the most appropriate sequence such that a coherent paragraph is formed:

P. Over time, such adaptations lead to significant evolutionary changes with the potential to shape the development of new species.

Q. In natural world, organisms constantly adapt to their environments in response to challenges and opportunities.

R. This process of adaptation is driven by the principle of natural selection, where favorable traits increase an organism's chances of survival and reproduction.

S. As environments change, organisms that can adapt their behavior, structure and physiology to such changes are more likely to survive.

A stick of length one meter is broken at two locations at distances of $b_1$ and $b_2$ from the origin (0), as shown in the figure. Note that 0<b $b_2<1$. Which one of the following is NOT a necessary condition for forming a triangle using the three pieces?

$$ \text { Note: All lengths are in meter. The figure shown is representative. } $$

Eight students (P, Q, R, S, T, U, V, and W) are playing musical chairs. The figure indicates their order of position at the start of the game. They play the game by moving forward in a circle in the clockwise direction.

After the $1^{\text {st }}$ round, $4^{\text {th }}$ student behind P leaves the game. After $2^{\text {nd }}$ round, $5^{\text {th }}$ student behind Q leaves the game. After $3^{\text {rd }}$ round, $3^{\text {rd }}$ student behind V leaves the game. After $4^{\text {th }}$ round, $4^{\text {th }}$ student behind $U$ leaves the game. Who all are left in the game after the $4^{\text {th }}$ round?

Note: The figure shown is representative.

The table lists the top 5 nations according to the number of gold medals won in a tournament; also included are the number of silver and the bronze medals won by them. Based only on the data provided in the table, which one of the following statements is INCORRECT?

$$ \begin{array}{|c|c|c|c|} \hline \text { Nation } & \text { Gold } & \text { Silver } & \text { Bronze } \\ \hline \text { USA } & 40 & 44 & 41 \\ \hline \text { Canada } & 39 & 27 & 24 \\ \hline \text { Japan } & 20 & 12 & 13 \\ \hline \text { Australia } & 17 & 19 & 16 \\ \hline \text { France } & 16 & 26 & 22 \\ \hline \end{array} $$