The GATE Grind

GATE 2019 EC – Previous Year Questions with Solutions

All 65 questions of GATE 2019 EC with answers and explanations. Read each question, then practise it by topic or as a full paper.

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  1. Question 1 (1 mark, Multiple choice) – The strategies that the company to sell its products house-to-house marketing.
  2. Question 2 (1 mark, Multiple choice) – The boat arrived dawn.
  3. Question 3 (1 mark, Multiple choice) – It would take one machine 4 hours to complete a production order and another machine 2 hours to complete the same order. If both machines work…
  4. Question 4 (1 mark, Multiple choice) – Five different books (P, Q, R, S, T) are to be arranged on a shelf. The books R and S are to be arranged first and second, respectively from the right…
  5. Question 5 (1 mark, Multiple choice) – When he did not come home, she him lying dead on the roadside somewhere.
  6. Question 6 (2 marks, Multiple choice) – Four people are standing in a line facing you. They are Rahul, Mathew, Seema and Lohit. One is an engineer, one is a doctor, one a teacher and another…
  7. Question 7 (2 marks, Multiple choice) – The bar graph in Panel (a) shows the proportion of male and female illiterates in 2001 and 2011. The proportions of males and females in 2001 and 2011…
  8. Question 8 (2 marks, Multiple choice) – "Indian history was written by British historians – extremely well documented and researched, but not always impartial. History had to serve its…
  9. Question 9 (2 marks, Multiple choice) – Two design consultants, P and Q, started working from 8 AM for a client. The client budgeted a total of USD 3000 for the consultants. P stopped…
  10. Question 10 (2 marks, Multiple choice) – Five people P, Q, R, S and T work in a bank. P and Q don't like each other but have to share an office till T gets a promotion and moves to the big…
  11. Question 11 (1 mark, Multiple choice) – Which one of the following functions is analytic over the entire complex plane?
  12. Question 12 (1 mark, Multiple choice) – The families of curves represented by the solution of the equation dydx=-( xy)n for n=-1 and n=+1, respectively, are
  13. Question 13 (1 mark, Multiple choice) – Let H(z) be the z-transform of a real-valued discrete-time signal h[n]. If P(z)=H(z)H(1z) has a zero at z=12+12j, and P(z) has a total of four zeros,…
  14. Question 14 (1 mark, Multiple choice) – Consider the two-port resistive network shown in the figure. When an excitation of 5 V is applied across Port 1, and Port 2 is shorted, the current…
  15. Question 15 (1 mark, Multiple choice) – Let Y(s) be the unit-step response of a causal system having a transfer function G(s)=3-s(s+1)(s+3) that is, Y(s)=G(s)s. The forced response of the…
  16. Question 16 (1 mark, Multiple choice) – For an LTI system, the Bode plot for its gain is as illustrated in the figure shown. The number of system poles N p and the number of system zeros N z…
  17. Question 17 (1 mark, Multiple choice) – A linear Hamming code is used to map 4-bit messages to 7-bit codewords. The encoder mapping is linear. If the message 0001 is mapped to the codeword…
  18. Question 18 (1 mark, Multiple choice) – Which one of the following options describes correctly the equilibrium band diagram at T=300 K of a Silicon pnn+p++ configuration shown in the figure?
  19. Question 19 (1 mark, Multiple choice) – The correct circuit representation of the structure shown in the figure is
  20. Question 20 (1 mark, Multiple choice) – The figure shows the high-frequency C-V curve of a MOS capacitor (at T = 300 K) with ms=0 V and no oxide charges. The flat-band, inversion, and…
  21. Question 21 (1 mark, Multiple choice) – What is the electric flux ( E d a) through a quarter-cylinder of height H (as shown in the figure) due to an infinitely long line charge along the…
  22. Question 22 (1 mark, Multiple choice) – In the table shown, List I and List II, respectively, contain terms appearing on the left-hand side and the right-hand side of Maxwell's equations (in…
  23. Question 23 (1 mark, Multiple choice) – A standard CMOS inverter is designed with equal rise and fall times ( n= p). If the width of the pMOS transistor in the inverter is increased, what…
  24. Question 24 (1 mark, Multiple choice) – In the circuit shown, what are the values of F for EN = 0 and EN = 1, respectively?
  25. Question 25 (1 mark, Multiple choice) – In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?
  26. Question 26 (1 mark, Numerical answer) – The value of the contour integral 12 j(z+1z)2dz evaluated over the unit circle z =1 is .
  27. Question 27 (1 mark, Numerical answer) – The number of distinct eigenvalues of the matrix A=bmatrix2&2&3&3\\0&1&1&1\\0&0&3&3\\0&0&0&2bmatrix is equal to .
  28. Question 28 (1 mark, Numerical answer) – If X and Y are random variables such that E[2X+Y]=0 and E[X+2Y]=33, then E[X]+E[Y]= .
  29. Question 29 (1 mark, Numerical answer) – The value of the integral 0 y xx\,dx\,dy is equal to .
  30. Question 30 (1 mark, Numerical answer) – Let Z be an exponential random variable with mean 1. That is, the cumulative distribution function of Z is given by F Z(x)=cases1-e-x&if x0\\0&if…
  31. Question 31 (1 mark, Numerical answer) – Consider the signal f(t)=1+2( t)+3(23t)+4(2t+4), where t is in seconds. Its fundamental time period, in seconds, is .
  32. Question 32 (1 mark, Numerical answer) – The baseband signal m(t) shown in the figure is phase-modulated to generate the PM signal (t)=(2 f ct+k\,m(t)). The time t on the x-axis in the figure…
  33. Question 33 (1 mark, Numerical answer) – The radiation resistance of a small dipole current element of length l at a frequency of 3 GHz is 3 ohms. If the length is changed by 1%, then the…
  34. Question 34 (1 mark, Numerical answer) – In the circuit shown, V s is a square wave of period T with maximum and minimum values of 8 V and -10 V, respectively. R 1=R 2=50\ . The average value…
  35. Question 35 (1 mark, Numerical answer) – In the circuit shown, the clock frequency, i.e., the frequency of the Clk signal, is 12 kHz. The frequency of the signal at Q 2 is kHz.
  36. Question 36 (2 marks, Multiple choice) – Consider a differentiable function f(x) on the set of real numbers such that f(-1)=0 and f'(x) 2. Given these conditions, which one of the following…
  37. Question 37 (2 marks, Multiple choice) – Consider the line integral C(x\,dy-y\,dx), the integral being taken in a counterclockwise direction over the closed curve C that forms the boundary of…
  38. Question 38 (2 marks, Multiple choice) – Consider a six-point decimation-in-time Fast Fourier Transform (FFT) algorithm, for which the signal-flow graph corresponding to X[1] is shown in the…
  39. Question 39 (2 marks, Multiple choice) – It is desired to find a three-tap causal filter which gives zero signal as an output to an input of the form x[n]=c 1(-j n2)+c 2(j n2), where c 1 and…
  40. Question 40 (2 marks, Multiple choice) – In the circuit shown, if v(t)=2(1000t) volts, R=1\ k and C=1\ F, then the steady-state current i(t), in milliamperes (mA), is
  41. Question 41 (2 marks, Multiple choice) – Consider a causal second-order system with the transfer function G(s)=11+2s+s2 with a unit-step R(s)=1s as an input. Let C(s) be the corresponding…
  42. Question 42 (2 marks, Multiple choice) – The block diagram of a system is illustrated in the figure shown, where X(s) is the input and Y(s) is the output. The transfer function H(s)=Y(s)X(s)…
  43. Question 43 (2 marks, Multiple choice) – Let the state-space representation of an LTI system be x(t)=Ax(t)+Bu(t), y(t)=Cx(t)+du(t) where A,B,C are matrices, d is a scalar, u(t) is the input…
  44. Question 44 (2 marks, Multiple choice) – A single bit, equally likely to be 0 and 1, is to be sent across an additive white Gaussian noise (AWGN) channel with power spectral density N 0/2.…
  45. Question 45 (2 marks, Multiple choice) – The quantum efficiency () and responsivity (R) at a wavelength (in m) in a p-i-n photodetector are related by
  46. Question 46 (2 marks, Multiple choice) – Two identical copper wires W1 and W2, placed in parallel as shown in the figure, carry currents I and 2I, respectively, in opposite directions. If the…
  47. Question 47 (2 marks, Multiple choice) – The dispersion equation of a waveguide, which relates the wavenumber k to the frequency , is k()=(1/c)2- 02 where the speed of light c=3108 m/s, and 0…
  48. Question 48 (2 marks, Multiple choice) – In the circuit shown, the breakdown voltage and the maximum current of the Zener diode are 20 V and 60 mA, respectively. The values of R 1 and R L are…
  49. Question 49 (2 marks, Multiple choice) – The state transition diagram for the circuit shown is
  50. Question 50 (2 marks, Multiple choice) – In the circuits shown, the threshold voltage of each nMOS transistor is 0.6 V. Ignoring the effect of channel length modulation and body bias, the…
  51. Question 51 (2 marks, Numerical answer) – The RC circuit shown below has a variable resistance R(t) given by the following expression: R(t)=R 0(1- tT)for 0 t<T where R 0=1\ , and C=1 F. We are…
  52. Question 52 (2 marks, Numerical answer) – Consider a unity feedback system, as in the figure shown, with an integral compensator Ks and open-loop transfer function G(s)=1s2+3s+2 where K>0. The…
  53. Question 53 (2 marks, Numerical answer) – Consider the homogeneous ordinary differential equation x2d2ydx2-3xdydx+3y=0, x>0 with y(x) as a general solution. Given that y(1)=1 and y(2)=14, the…
  54. Question 54 (2 marks, Numerical answer) – Let h[n] be a length-7 discrete-time finite impulse response filter, given by h[0]=4,\ h[1]=3,\ h[2]=2,\ h[3]=1,\ h[-1]=-3,\ h[-2]=-2,\ h[-3]=-1, and…
  55. Question 55 (2 marks, Numerical answer) – Let a random process Y(t) be described as Y(t)=h(t)*X(t)+Z(t), where X(t) is a white noise process with power spectral density S X(f)=5 W/Hz. The…
  56. Question 56 (2 marks, Numerical answer) – A voice signal m(t) is in the frequency range 5 kHz to 15 kHz. The signal is amplitude-modulated to generate an AM signal f(t)=A(1+m(t))2 f ct, where…
  57. Question 57 (2 marks, Numerical answer) – A random variable X takes values -1 and +1 with probabilities 0.2 and 0.8, respectively. It is transmitted across a channel which adds noise N, so…
  58. Question 58 (2 marks, Numerical answer) – A Germanium sample of dimensions 1 cm 1 cm is illuminated with a 20 mW, 600 nm laser light source as shown in the figure. The illuminated sample…
  59. Question 59 (2 marks, Numerical answer) – In an ideal pn junction with an ideality factor of 1 at T=300 K, the magnitude of the reverse-bias voltage required to reach 75% of its reverse…
  60. Question 60 (2 marks, Numerical answer) – Consider a long-channel MOSFET with a channel length 1\ m and width 10\ m. The device parameters are acceptor concentration N A=51016\ cm-3, electron…
  61. Question 61 (2 marks, Numerical answer) – A rectangular waveguide of width w and height h has cut-off frequencies for TE 10 and TE 11 modes in the ratio 1 : 2. The aspect ratio w/h, rounded…
  62. Question 62 (2 marks, Numerical answer) – In the circuit shown, V s is a 10 V square wave of period T=4 ms with R=500\ and C=10\ F. The capacitor is initially uncharged at t=0, and the diode…
  63. Question 63 (2 marks, Numerical answer) – A CMOS inverter, designed to have a mid-point voltage V I equal to half of V dd, as shown in the figure, has the following parameters: V dd=3 V nC…
  64. Question 64 (2 marks, Numerical answer) – In the circuit shown, the threshold voltages of the pMOS ( V tp ) and nMOS (V tn) transistors are both equal to 1 V. All the transistors have the same…
  65. Question 65 (2 marks, Numerical answer) – In the circuit shown, V 1=0 and V 2=V dd. The other relevant parameters are mentioned in the figure. Ignoring the effect of channel length modulation…