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GATE 2025 EC – Previous Year Questions with Solutions

All 65 questions of GATE 2025 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) – 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.…
  2. Question 2 (1 mark, Multiple choice) – Had I learnt acting as a child, I a famous film star. Select the most appropriate option to complete the above sentence.
  3. Question 3 (1 mark, Multiple choice) – The 12 musical notes are given as C, C\#, D, D\#, E, F, F\#, G, G\#, A, A\#, and B. Frequency of each note is [12]2 times the frequency of the…
  4. Question 4 (1 mark, Multiple choice) – The following figures show three curves generated using an iterative algorithm. The total length of the curve generated after ‘Iteration n’ is: Note:…
  5. Question 5 (1 mark, Multiple choice) – Which one of the following plots represents f(x)=- x x, where x is a non-zero real number? Note: The figures shown are representative.
  6. Question 6 (2 marks, Multiple choice) – Identify the option that has the most appropriate sequence such that a coherent paragraph is formed: P. Over time, such adaptations lead to…
  7. Question 7 (2 marks, Multiple choice) – 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 1<b 2<1.…
  8. Question 8 (2 marks, Multiple choice) – 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…
  9. Question 9 (2 marks, Multiple choice) – 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…
  10. Question 10 (2 marks, Multiple choice) – An organization allows its employees to work independently on consultancy projects but charges an overhead on the consulting fee. The overhead is 20%…
  11. Question 11 (1 mark, Multiple choice) – Consider the matrix A below: A=bmatrix2&3&4&5\\0&6&7&8\\0&0&&\\0&0&0&bmatrix For which of the following combinations of , , and , is the rank of A at…
  12. Question 12 (1 mark, Multiple choice) – Consider the following series: (i) n=11 n (ii) n=11n(n+1) (iii) n=11n! Choose the correct option.
  13. Question 13 (1 mark, Multiple choice) – 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…
  14. Question 14 (1 mark, Multiple choice) – Consider a frequency-modulated (FM) signal f(t)=A c(2 f ct+3(2 f 1t)+4(6 f 1t)), where A c and f c are, respectively, the amplitude and frequency (in…
  15. Question 15 (1 mark, Multiple choice) – Consider an additive white Gaussian noise (AWGN) channel with bandwidth W and noise power spectral density N 02. Let P av denote the average transmit…
  16. Question 16 (1 mark, Multiple choice) – The Nyquist plot of a system is given in the figure below. Let P, Q, R, and S be the positive frequencies at the points P, Q, R, and S, respectively.…
  17. Question 17 (1 mark, Multiple choice) – 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…
  18. Question 18 (1 mark, Multiple choice) – Consider a continuous-time, real-valued signal f(t) whose Fourier transform F()= -f(t)(-j t)\,dt exists. Which one of the following statements is…
  19. Question 19 (1 mark, Multiple choice) – Consider a part of an electrical network as shown below. Some node voltages, and the current flowing through the 3 Ω resistor are indicated. The…
  20. Question 20 (1 mark, Multiple choice) – 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…
  21. Question 21 (1 mark, Multiple choice) – A simplified small-signal equivalent circuit of a BJT-based amplifier is given below. The small-signal voltage gain v o/v s (in V/V) is .
  22. Question 22 (1 mark, Multiple choice) – The ideal BJT in the circuit given below is biased in the active region with a of 100. If I B is 10 μA, then V CE (in Volts, rounded off to two…
  23. Question 23 (1 mark, Multiple choice) – A 3-input majority logic gate has inputs X, Y, and Z. The output F of the gate is logic ‘1’ if two or more of the inputs are logic ‘1’. The output F…
  24. Question 24 (1 mark, Multiple choice) – 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…
  25. Question 25 (1 mark, Multiple select) – Consider the function f:RR, defined as f(x)=2x3-3x2-12x+1. Which of the following statements is/are correct? (Here, R is the set of real numbers.)
  26. Question 26 (1 mark, Multiple choice) – Consider the unity-negative-feedback system shown in Figure (i) below, where gain K0. The root locus of this system is shown in Figure (ii) below. For…
  27. Question 27 (1 mark, Multiple select) – Let x[n] be a discrete-time signal whose z-transform is X(z). Which of the following statements is/are TRUE?
  28. Question 28 (1 mark, Multiple select) – 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:…
  29. Question 29 (1 mark, Multiple select) – Which of the following statements is/are TRUE with respect to an ideal opamp?
  30. Question 30 (1 mark, Multiple select) – Which of the following statements is/are TRUE with respect to ideal MOSFET-based DC-coupled single-stage amplifiers having finite load resistors?
  31. Question 31 (1 mark, Multiple select) – Which of the following can be used as an n-type dopant for silicon? Select the correct option(s).
  32. Question 32 (1 mark, Numerical answer) – The function y(t) satisfies t2y''(t)-2ty'(t)+2y(t)=0, where y'(t) and y''(t) denote the first and second derivatives of y(t), respectively. Given…
  33. Question 33 (1 mark, Numerical answer) – The generator matrix of a (6,3) binary linear block code is given by G=bmatrix1&0&0&1&0&1\\0&1&0&0&1&1\\0&0&1&1&1&0bmatrix. The minimum Hamming…
  34. Question 34 (1 mark, Numerical answer) – All the components in the bandpass filter given below are ideal. The lower -3 dB frequency of the filter is 1 MHz. The upper -3 dB frequency (in MHz,…
  35. Question 35 (1 mark, Numerical answer) – A 4-bit weighted-resistor DAC with inputs b 3, b 2, b 1, and b 0 (MSB to LSB) is designed using an ideal opamp, as shown below. The switches are…
  36. Question 36 (2 marks, Multiple choice) – Let G(s)=110s2 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.…
  37. Question 37 (2 marks, Multiple choice) – Consider the polynomial p(s)=s5+7s4+3s3-33s2+2s-40. Let (L,I,R) be defined as follows: L is the number of roots of p(s) with negative real parts. I is…
  38. Question 38 (2 marks, Multiple choice) – Consider a continuous-time finite-energy signal f(t) whose Fourier transform vanishes outside the frequency interval [- c, c], where c is in rad/sec.…
  39. Question 39 (2 marks, Multiple choice) – 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(200t). What should be…
  40. Question 40 (2 marks, Multiple choice) – The Z-parameter matrix of a two port network relates the port voltages and port currents as follows: bmatrixV 1\ 2bmatrix=ZbmatrixI 1\ 2bmatrix The…
  41. Question 41 (2 marks, Multiple choice) – 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…
  42. Question 42 (2 marks, Multiple choice) – Consider a real-valued random process f(t)= n=1Na n\,p(t-nT), where T>0 and N is a positive integer. Here, p(t)=1 for t[0,0.5T] and 0 otherwise. The…
  43. Question 43 (2 marks, Multiple choice) – 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…
  44. Question 44 (2 marks, Multiple choice) – A 10-bit analog-to-digital converter (ADC) has a sampling frequency of 1 MHz and a full scale voltage of 3.3 V. For an input sinusoidal signal with…
  45. Question 45 (2 marks, Multiple choice) – A positive-edge-triggered sequential circuit is shown below. There are no timing violations in the circuit. Input P0 is set to logic ‘0’ and P1 is set…
  46. Question 46 (2 marks, Multiple choice) – The intrinsic carrier concentration of a semiconductor is 2.51016 /m3 at 300 K. If the electron and hole mobilities are 0.15 m2/Vs and 0.05 m2/Vs,…
  47. Question 47 (2 marks, Multiple choice) – In the circuit shown, the identical transistors Q1 and Q2 are biased in the active region with =120. The Zener diode is in the breakdown region with V…
  48. Question 48 (2 marks, Multiple choice) – The electron mobility n in a non-degenerate germanium semiconductor at 300 K is 0.38 m2/Vs. The electron diffusivity D n at 300 K (in cm2/s, rounded…
  49. Question 49 (2 marks, Multiple choice) – A square metal sheet of 4 m × 4 m is placed on the x-y plane as shown in the figure below. If the surface charge density (in μC/m2) on the sheet is…
  50. Question 50 (2 marks, Multiple choice) – An electric field of 0.01 V/m is applied along the length of a copper wire of circular cross-section with diameter 1 mm. Copper has a conductivity of…
  51. Question 51 (2 marks, Multiple select) – 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…
  52. Question 52 (2 marks, Multiple select) – Which of the following statements involving contour integrals (evaluated counter-clockwise) on the unit circle C in the complex plane is/are TRUE?
  53. Question 53 (2 marks, Multiple select) – 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…
  54. Question 54 (2 marks, Multiple select) – The random variable X takes values in \-1,0,1\ with probabilities P(X=-1)=P(X=1)= and P(X=0)=1-2, where 0<<12. Let g() denote the entropy of X (in…
  55. Question 55 (2 marks, Multiple select) – Let f(t) be a periodic signal with fundamental period T 0>0. Consider the signal y(t)=f( t), where >1. The Fourier series expansions of f(t) and y(t)…
  56. Question 56 (2 marks, Multiple select) – Consider a system represented by the block diagram shown below. Which of the following signal flow graphs represent(s) this system? Choose the correct…
  57. Question 57 (2 marks, Multiple select) – 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?
  58. Question 58 (2 marks, Numerical answer) – Two fair dice (with faces labeled 1, 2, 3, 4, 5, and 6) are rolled. Let the random variable X denote the sum of the outcomes obtained. The expectation…
  59. Question 59 (2 marks, Numerical answer) – Consider the vectors a=bmatrix1\\1bmatrix, b=bmatrix0\\32bmatrix. For real-valued scalar variable x, the value of x\ ax- b\ 2 is (rounded off to two…
  60. Question 60 (2 marks, Numerical answer) – X and Y are Bernoulli random variables taking values in \0,1\. The joint probability mass function of the random variables is given by:…
  61. Question 61 (2 marks, Numerical answer) – The diode in the circuit shown below is ideal. The input voltage (in Volts) is given by V I=10100 t, where time t is in seconds. The time duration (in…
  62. Question 62 (2 marks, Numerical answer) – In the circuit shown below, the AND gate has a propagation delay of 1 ns. The edge-triggered flip-flops have a set-up time of 2 ns, a hold-time of 0…
  63. Question 63 (2 marks, Numerical answer) – An ideal p-n junction germanium diode has a reverse saturation current of 10 μA at 300 K. The voltage (in Volts, rounded off to two decimal places) to…
  64. Question 64 (2 marks, Numerical answer) – A 50 Ω lossless transmission line is terminated with a load Z L of (50-j75) Ω. If the average incident power on the line is 10 mW, then the average…
  65. Question 65 (2 marks, Numerical answer) – Two resistors are connected in a circuit loop of area 5 m2, as shown in the figure below. The circuit loop is placed on the x-y plane. When a…