The GATE Grind

GATE 2021 MT – Previous Year Questions with Solutions

All 65 questions of GATE 2021 MT with answers and explanations. Read each question, then practise it by topic or as a full paper.

Practise this paper in The GATE Grind →

  1. Question 1 (1 mark, Multiple choice) – Five persons P, Q, R, S, T sit in a row facing the same direction. P and T cannot sit at either end; P must not sit adjacent to S; R is second from…
  2. Question 2 (1 mark, Multiple choice) – Consider: (i) The number of candidates who appear for the GATE examination is staggering. (ii) A number of candidates from my class are appearing for…
  3. Question 3 (1 mark, Multiple choice) – Digital watch X beeps every 30 seconds and watch Y every 32 seconds. They beep together at 10 AM. The immediately next time they beep together is .
  4. Question 4 (1 mark, Multiple choice) – If =2, =3, +=5, and =10, then (-)2= .
  5. Question 5 (1 mark, Multiple choice) – Mr X’s front door faces east. He leaves through the back door directly opposite it, walks 50 m straight, turns right, then walks 50 m. His final…
  6. Question 6 (2 marks, Multiple choice) – Statement 1: All entrepreneurs are wealthy. Statement 2: All wealthy are risk seekers. Conclusion I: All risk seekers are wealthy. Conclusion II: Only…
  7. Question 7 (2 marks, Multiple choice) – A box contains 15 blue and 45 black balls. Two are selected randomly without replacement. The probability that the first is blue and the second black…
  8. Question 8 (2 marks, Multiple choice) – The ratio of the area of the incircle to that of the circumcircle of an equilateral triangle is .
  9. Question 9 (2 marks, Multiple choice) – A square sheet has side 1 unit. Fold along its main diagonal, then along the folded shape’s symmetry line, then again along its new symmetry line. The…
  10. Question 10 (2 marks, Multiple choice) – “The world is going through the worst pandemic in the past hundred years. The air travel industry is facing a crisis, as the resulting quarantine…
  11. Question 11 (1 mark, Multiple choice) – The eigenvalues of bmatrix1&0&-1\\0&1&0\\-1&0&1bmatrix are .
  12. Question 12 (1 mark, Multiple choice) – Which is a homogeneous function of degree three?
  13. Question 13 (1 mark, Multiple choice) – For vector field V(x,y,z) with components V x,V y,V z depending on x,y,z, its divergence is .
  14. Question 14 (1 mark, Multiple choice) – Which diagram shows the centre-split defect in rolling?
  15. Question 15 (1 mark, Multiple choice) – Single-crystal nickel-based superalloy turbine blades for aero-engines are manufactured using .
  16. Question 16 (1 mark, Multiple choice) – Elements A and B have the same crystal structure. For a dilute solution of B in A, which is true? Here H mix is mixing enthalpy, a B activity and X B…
  17. Question 17 (1 mark, Multiple choice) – For the uniaxial tensile stress–strain behaviour of polycrystalline aluminium, which statement is FALSE?
  18. Question 18 (1 mark, Multiple choice) – Which statement about creep deformation is FALSE?
  19. Question 19 (1 mark, Multiple choice) – Which element alloyed with iron is a ferrite stabilizer?
  20. Question 20 (1 mark, Multiple choice) – Which is the correct decreasing sequence of quenching power for steel heat treatment?
  21. Question 21 (1 mark, Multiple choice) – For a zero-order chemical reaction, which statement is FALSE?
  22. Question 22 (1 mark, Multiple choice) – Which element oxidizes first in basic oxygen steelmaking?
  23. Question 23 (1 mark, Multiple choice) – Which is a hydrometallurgical operation?
  24. Question 24 (1 mark, Numerical answer) – The value of x02(5x)/2x is (nearest integer).
  25. Question 25 (1 mark, Numerical answer) – Annealed-specimen grain size X has a symmetric distribution with mean =5 μm and standard deviation =0.5 μm. Given P(X+2)=0.98, the percentage with…
  26. Question 26 (1 mark, Numerical answer) – Given E Ni2+/Ni=-0.25 V and F=96500 C/mol, the standard chemical potential Ni2+ at 298 K is J/mol (nearest integer).
  27. Question 27 (1 mark, Numerical answer) – Copper melts at 1358 K with melting enthalpy 13400 J/mol. Its liquid-to-solid free-energy change at 1058 K is J/mol (nearest integer). Assume C…
  28. Question 28 (1 mark, Numerical answer) – A body has stress tensor bmatrix50&0&0\\0&200&0\\0&0&100bmatrix MPa. For yielding under Tresca’s criterion, its uniaxial tensile yield stress must be…
  29. Question 29 (1 mark, Numerical answer) – For homogeneous spherical-solid nucleation in liquid at fixed undercooling, a 20% rise in nucleus surface energy causes a % increase in critical…
  30. Question 30 (1 mark, Numerical answer) – Iron’s room-temperature saturation magnetization is 1700 kA/m and lattice parameter 0.287 nm. Its per-atom magnetic moment is 10-23 A·m2 (one decimal…
  31. Question 31 (1 mark, Numerical answer) – An FCC crystal’s first X-ray reflection is at Bragg angle =30. The second reflection has Bragg angle degrees (one decimal place).
  32. Question 32 (1 mark, Numerical answer) – Steel containing 0.6 wt.% C is cooled slowly from 900 °C to room temperature. The proeutectoid ferrite fraction is (two decimal places). Given…
  33. Question 33 (1 mark, Numerical answer) – Polyethylene’s degree of polymerization is 30000. Its average molecular weight is g/mol (nearest integer). Atomic weights of C and H are 12 and 1.
  34. Question 34 (1 mark, Numerical answer) – Water flows over a finite plate. At distance x=x 1 from the leading edge, V x=0.5y-0.5y3. The boundary-layer thickness there is m (two decimal…
  35. Question 35 (1 mark, Numerical answer) – A crystal’s vacancy concentration doubles when temperature increases from 27 °C to 127 °C. Vacancy-formation enthalpy is kJ/mol (two decimal places).…
  36. Question 36 (2 marks, Multiple choice) – The minimum value of y=x2-2x+4 is .
  37. Question 37 (2 marks, Multiple choice) – Match forming-process diagrams P–S in Column I to names in Column II. 1. Extrusion 2. Rolling 3. Deep drawing 4. Open-die forging
  38. Question 38 (2 marks, Multiple choice) – Match nondestructive testing methods P–S with principles 1–4. P. Dye penetrant test Q. Radiography R. Eddy current test S. Ultrasonic inspection 1.…
  39. Question 39 (2 marks, Multiple choice) – The number of degrees of freedom for M(s)+CO 2(g) MO(s)+CO(g) is .
  40. Question 40 (2 marks, Multiple choice) – Which condition gives the binary A–B phase diagram shown? H mixsolid and H mixliquid denote solid and liquid mixing enthalpies.
  41. Question 41 (2 marks, Multiple choice) – Without external stress, which statement about point-defect/dislocation interaction is FALSE?
  42. Question 42 (2 marks, Multiple choice) – Single-crystal aluminium is in uniaxial tension along [112]. At applied stress 100 MPa and critical resolved shear stress 25 MPa, which slip system…
  43. Question 43 (2 marks, Multiple choice) – The shown steady one-dimensional temperature distribution is across adjacent refractory blocks of unit cross-sectional area and conductivities k 1,k…
  44. Question 44 (2 marks, Multiple choice) – Fully developed one-dimensional Newtonian flow in a horizontal pipe of radius R has v z=( P/L)(R2-r2)/(4). Here P=P 1-P 2, viscosity is , radial…
  45. Question 45 (2 marks, Multiple choice) – Match terms to unit processes. P. Submerged entry nozzle Q. Electric heating R. Raceway zone S. Oxygen lancing 1. Ladle furnace 2. Continuous casting…
  46. Question 46 (2 marks, Multiple choice) – A blast furnace uses hematite ore with 80% Fe 2O 3 and 20% gangue. Coke use is 600 kg per ton hot metal, with 85% C and 15% ash. Hot metal is 95.5% Fe…
  47. Question 47 (2 marks, Numerical answer) – Use Newton–Raphson on f(x)=x- x with initial guess 0.5 radians. The root estimate after one iteration is (three decimal places).
  48. Question 48 (2 marks, Numerical answer) – The work by F=2x i+3y j along a straight line from (0,0) to (1,2) is (nearest integer).
  49. Question 49 (2 marks, Numerical answer) – A coin is tossed three times. Given more heads than tails, the probability of exactly one tail is (two decimal places).
  50. Question 50 (2 marks, Numerical answer) – A 3000 W machine makes a continuous fillet weld at 6 mm/s. Heat-transfer factor is 0.6, melting factor 0.5, and unit energy for melting 6 J/mm3. The…
  51. Question 51 (2 marks, Numerical answer) – Liquid iron is cast into a spherical sand mould of radius 6 cm and a cubical sand mould of edge 12 cm. The sphere solidifies in 60 minutes. The cube…
  52. Question 52 (2 marks, Numerical answer) – True strain for 60% height reduction in forging is (two decimal places).
  53. Question 53 (2 marks, Numerical answer) – For 2Cu(s)+SO 2(g) Cu 2S(s)+O 2(g) at 973 K, (p O 2/p SO 2)= (two decimal places). Given G=-100 kJ for 2Cu(s)+0.5S 2(g) Cu 2S(s) and G=292 kJ for SO…
  54. Question 54 (2 marks, Numerical answer) – One mole of ideal gas at 10 atm and 300 K expands reversibly and adiabatically to 1 atm. Work done by the gas is J (nearest integer). Given R=8.314 J…
  55. Question 55 (2 marks, Numerical answer) – The figure shows the entropy versus temperature plot of a reversible engine cycle. For T 1=200 K and T 2=600 K, its efficiency is % (two decimal…
  56. Question 56 (2 marks, Numerical answer) – Two dislocation lines parallel to z lie in the x–z plane as shown. The glide force exerted by the edge dislocation on the screw dislocation is N…
  57. Question 57 (2 marks, Numerical answer) – A shear stress 100 MPa bows a dislocation between precipitates spaced 0.2 μm. If spacing increases to 0.5 μm, the needed shear stress is MPa (nearest…
  58. Question 58 (2 marks, Numerical answer) – A plate is in plane strain with zz=0, xx= yy0, and xy= xz= yz=0. For Poisson ratio 0.3, zz/ xx is (one decimal place).
  59. Question 59 (2 marks, Numerical answer) – An infinite metal plate has a central through-thickness crack of full length 80/ mm. Its maximum mode-I applied stress is MPa (nearest integer).…
  60. Question 60 (2 marks, Numerical answer) – An A–B alloy with 5 wt.% B solidifies without convection, with the shown hypothetical eutectic phase diagram. Under steady state, the critical…
  61. Question 61 (2 marks, Numerical answer) – A thick steel plate with 0.1 wt.% C is carburized at 950 °C, keeping surface C at 1.1 wt.%. After 9 hours, the depth where C reaches 0.6 wt.% is mm…
  62. Question 62 (2 marks, Numerical answer) – At 25 °C, iron corrodes in deaerated pH-3 acid with corrosion current density 4 μA/cm2. Its corrosion potential is V (two decimal places). Given…
  63. Question 63 (2 marks, Numerical answer) – An interstitial atom just fits an octahedral void in BCC iron without distorting the structure. If iron’s atomic radius is 0.124 nm, the interstitial…
  64. Question 64 (2 marks, Numerical answer) – Nickel oxidizes isothermally at 800 K for 400 s, gaining 2 mg/cm2. Its weight gain after 1600 s is mg/cm2 (nearest integer). Assume gain proportional…
  65. Question 65 (2 marks, Numerical answer) – A solid sphere of radius 0.5 m is enclosed by a hollow sphere of radius 1 m. Radiation exchanges between the small sphere’s outer surface (1) and…