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GATE 2016 EC (EC3) – Previous Year Questions with Solutions

All 65 questions of GATE 2016 EC (EC3) 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) – An apple costs Rs. 10 and an onion costs Rs. 8. Select the most suitable sentence with respect to grammar and usage.
  2. Question 2 (1 mark, Multiple choice) – The Buddha said, “Holding on to anger is like grasping a hot coal with the intent of throwing it at someone else; you are the one who gets burnt.”…
  3. Question 3 (1 mark, Multiple choice) – M has one son Q and one daughter R, with no other children. E is P’s mother and M’s daughter-in-law. How is P related to M?
  4. Question 4 (1 mark, Multiple choice) – Which number least fits the set (324,441,97,64)?
  5. Question 5 (1 mark, Multiple choice) – Two constant-speed trains take 10 s and 15 s respectively to pass a telegraph post completely. Their lengths are 120 m and 150 m respectively. The…
  6. Question 6 (2 marks, Multiple choice) – A vehicle’s velocity along a straight line, in m/s, is plotted against time in seconds. How much does its odometer reading increase over the 7…
  7. Question 7 (2 marks, Multiple choice) – The overwhelming number of people infected with rabies in India has been flagged by the World Health Organization as a concern. Inoculating 70% of…
  8. Question 8 (2 marks, Multiple choice) – Four first-year undergraduates share a flat and give the oldest extra space. Manu is two months older than Sravan, who is three months younger than…
  9. Question 9 (2 marks, Multiple choice) – Find the area bounded by 3x+2y=14 and 2x-3y=5 in the first quadrant.
  10. Question 10 (2 marks, Multiple choice) – A straight line is fitted to ( x,y) data. It crosses the horizontal axis at x=0.1 and has slope −0.02. Its fitted y at x=5 is
  11. Question 11 (1 mark, Multiple choice) – Consider the matrix A=bmatrix&x\\&bmatrix. If its eigenvalues are +j and -j, the unknown x equals
  12. Question 12 (1 mark, Numerical answer) – For f(z)= z/z2, the residue at the pole z=0 is .
  13. Question 13 (1 mark, Numerical answer) – A biased coin gives a head with probability 0.3. It is tossed independently until a head appears. The probability that the first head occurs on toss…
  14. Question 14 (1 mark, Numerical answer) – The integral 01 dx/1-x equals .
  15. Question 15 (1 mark, Numerical answer) – Consider y=y+2x-x2, y(0)=1, for 0 x<, with exact solution y(x)=x2+ex. At x=0.1, the percentage difference between the exact solution and one iteration…
  16. Question 16 (1 mark, Multiple choice) – Let x(t)=(6 t)+(8 t), with t in seconds. The Nyquist sampling rate in samples/s for y(t)=x(2t+5) is
  17. Question 17 (1 mark, Multiple choice) – If x(t)=[ t/( t)]*[ t/( t)], where * denotes convolution, x(t) is
  18. Question 18 (1 mark, Multiple choice) – The signal x[n]=[n-3]+2[n-5] has z-transform X(z). If Y(z)=X(-z) is the transform of y[n], then
  19. Question 19 (1 mark, Multiple choice) – For the RLC circuit shown, v i(t)=2(200t)+4(500t) V. The output voltage is
  20. Question 20 (1 mark, Multiple choice) – The room-temperature I–V curves of diodes made from materials X,Y,Z are shown. They are uniformly doped and otherwise identical. With material band…
  21. Question 21 (1 mark, Multiple choice) – The figure shows the band diagram of a metal–oxide–semiconductor structure. Its surface region is in
  22. Question 22 (1 mark, Numerical answer) – The shown solar-cell I–V curve is measured under uniform illumination of 100\ mW/cm2. The cell area is 3\ cm2 and fill factor 0.7. Its maximum…
  23. Question 23 (1 mark, Numerical answer) – D1 and D2 are ideal, and the two capacitors are identical. RC is much greater than the ac period and the diodes do not break down in reverse bias. The…
  24. Question 24 (1 mark, Numerical answer) – For the circuit shown, assume V BE1=V EB2=0.7 V. The dc collector voltage V C2 in volts is .
  25. Question 25 (1 mark, Numerical answer) – For the 555 astable multivibrator shown, the oscillation frequency at output pin 3 in kHz is .
  26. Question 26 (1 mark, Multiple choice) – In an 8085, the accumulator is A7 hexadecimal and the carry flag is 0. After executing RLC, the accumulator and carry respectively are
  27. Question 27 (1 mark, Multiple choice) – The logic function realized by the circuit below is
  28. Question 28 (1 mark, Multiple choice) – The minimum number of 2-input NAND gates needed to implement a 2-input XOR is
  29. Question 29 (1 mark, Multiple choice) – For the feedback block diagram shown, the overall closed-loop gain G is
  30. Question 30 (1 mark, Multiple choice) – A unity-negative-feedback system has open-loop G(s)=2/[s(s+1)], as shown. Its steady-state error to a unit step is
  31. Question 31 (1 mark, Numerical answer) – A superheterodyne receiver has intermediate frequency 15 MHz and local oscillator frequency 3.5 GHz. The received signal is above the oscillator…
  32. Question 32 (1 mark, Numerical answer) – A 100 Hz bandlimited analogue baseband signal is sampled at the Nyquist rate. Samples are quantized into independent symbols with probabilities…
  33. Question 33 (1 mark, Multiple choice) – A binary baseband system transmits the pulse p(t)=cases1/T s,&0 t T s,\\0,&otherwise.cases Which graphical choice shows its matched-filter output…
  34. Question 34 (1 mark, Multiple choice) – A right-handed circularly polarized wave is normally incident on a plane perfect conductor. The reflected wave is
  35. Question 35 (1 mark, Multiple choice) – Faraday’s law of electromagnetic induction is described by which equation?
  36. Question 36 (2 marks, Multiple choice) – The initial-value problem y+12y+36y=0, y(0)=3, y(0)=-36 has solution
  37. Question 37 (2 marks, Multiple choice) – An orthogonal basis of R3 is e 1=(1,0,2), e 2=(0,1,0), e 3=(-2,0,1). Express u=(4,3,-3) in this basis.
  38. Question 38 (2 marks, Numerical answer) – A triangle in the xy plane is bounded by 2x=3y, y=0 and x=3. The volume above it and below x+y+z=6 is .
  39. Question 39 (2 marks, Multiple choice) – The integral (2 j)-1 c ez/(z-2)\,dz is taken anticlockwise around a closed contour. Its values with z=2 (i) inside and (ii) outside c are respectively
  40. Question 40 (2 marks, Multiple choice) – The signal 2(2 t/3)-( t) enters an LTI system with H(s)=es+e-s. If C k is the kth exponential Fourier-series coefficient of the output, C 3 equals
  41. Question 41 (2 marks, Multiple choice) – The choices shade regions of convergence in the z plane. For x[n]=2 n , -<n<, which choice gives its z-transform ROC?
  42. Question 42 (2 marks, Numerical answer) – The circuit has reached steady state before t=0, when the 3 Ω resistor burns out and becomes open. The current i(t), in amperes, at t=0+ is .
  43. Question 43 (2 marks, Numerical answer) – In the circuit shown, the current i in amperes, with its indicated downward direction, is .
  44. Question 44 (2 marks, Multiple choice) – The z-parameter matrix of the shown two-port network is
  45. Question 45 (2 marks, Numerical answer) – A continuous speech signal sampled at 8 kHz is grouped into N-sample blocks. Each DFT must be computed in real time by radix-2 decimation-in-frequency…
  46. Question 46 (2 marks, Multiple choice) – The direct-form FIR filter shown can be used to approximate a
  47. Question 47 (2 marks, Numerical answer) – An active npn BJT has the linear excess-electron base profile shown. Emitter–base junction area is 0.001\ cm2, base electron mobility is 800\…
  48. Question 48 (2 marks, Numerical answer) – Two unit-area MOS capacitors are shown. Figure I uses dielectric X of thickness t 1=1 nm and relative permittivity 4, and Y of thickness t 2=3 nm and…
  49. Question 49 (2 marks, Multiple choice) – The Zener I–V curves are shown in Figure I and their series circuit in Figure II. As the supply varies from 0 to 100 V, breakdown occurs in
  50. Question 50 (2 marks, Numerical answer) – In the shown circuit R 1=R 2=R 3=1\ , L=1 μH and C=1 μF. For V in=(106t), the overall voltage gain V out/V in is .
  51. Question 51 (2 marks, Multiple choice) – All transistors in the shown circuit operate in saturation, have nonzero channel-length modulation and negligible body effect. Its small-signal…
  52. Question 52 (2 marks, Numerical answer) – M1 in the shown circuit is saturated with g m=0.01 S. Ignore internal parasitic capacitances and set channel-length modulation to zero. The…
  53. Question 53 (2 marks, Multiple choice) – The figure gives a five-variable K-map for P,Q,R,S,X. The minimum sum-of-products expression is
  54. Question 54 (2 marks, Numerical answer) – In the shown circuit, NOR, multiplexer and inverter delays are 2 ns, 1.5 ns and 1 ns respectively. Inputs P,Q,R,S,T are applied simultaneously. The…
  55. Question 55 (2 marks, Multiple choice) – In the circuit shown, the bubbled NAND gate delay is 2 ns and the counter delay is zero. At a clock frequency of 1 GHz, the counter behaves as a
  56. Question 56 (2 marks, Multiple choice) – The first two rows of a cubic system's Routh table are arrayc ccs3&1&2K+3\2&2K&4array. The stable range of K is
  57. Question 57 (2 marks, Multiple choice) – A second-order LTI system obeys x 1+2x 1=3u(t), x 2+x 2=u(t). The output is c(t)=x 1(t). The system is
  58. Question 58 (2 marks, Numerical answer) – A single-loop negative-feedback system has G(s)=K(s+2)/(s2+2s+2) and H(s)=1, with real K>0. The breakaway-point location on its root locus is .
  59. Question 59 (2 marks, Multiple choice) – A wide-sense stationary process X(t) passes through the shown delay-and-subtract LTI system. If its autocorrelation is R X(), the output…
  60. Question 60 (2 marks, Numerical answer) – A voice-grade AWGN telephone channel has bandwidth 4.0 kHz and two-sided noise spectral density /2=2.510-5 W/Hz. To transmit at 52 kbps with…
  61. Question 61 (2 marks, Numerical answer) – A memoryless binary symmetric channel has bit error probability 10-5. If 105 bits are sent, the probability that no more than one bit is wrong is .
  62. Question 62 (2 marks, Numerical answer) – An air-filled rectangular waveguide has a=2.286 cm and b=1.016 cm. At 10 GHz, the propagation constant per metre of the propagating mode is .
  63. Question 63 (2 marks, Multiple choice) – For an air-filled rectangular waveguide with a=2.286 cm and b=1.016 cm, the increasing order of cutoff frequencies is
  64. Question 64 (2 marks, Numerical answer) – A 5 GHz radar uses one antenna for transmitting and receiving. The antenna gain is 150 and points at a target 1 km away with radar cross-section 3\…
  65. Question 65 (2 marks, Multiple choice) – For the charge-density profile shown, which graphical choice best describes the resultant potential distribution?