GATE 2020 CH – Previous Year Questions with Solutions
All 65 questions of GATE 2020 CH with answers and explanations. Read each question, then practise it by topic or as a full paper.
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- Question 1 – Rajiv Gandhi Khel Ratna Award was conferred Mary Kom, a six-time world boxing champion, recently in a ceremony the Rashtrapati Bhawan in New Delhi.
- Question 2 – Despite a string of poor performances, the chances of K. L. Rahul’s selection in the team are .
- Question 3 – Complete the analogy: Cover : Uncover :: Associate : .
- Question 4 – Floods affected the summer-sown kharif crops. Officials believe this loss can be recovered through winter-sown rabi crops so the country can achieve…
- Question 5 – Find the difference between the sum of the first 2n natural numbers and the sum of the first n odd natural numbers.
- Question 6 – Repo rate is the rate at which RBI lends to commercial banks; reverse repo is the rate at which RBI borrows from them. Which statement follows?
- Question 7 – P,Q,R,S,T,U,V,W sit around a circular table. S is opposite W; U is second to the right of R; T is third to the left of R; V neighbours S. Which must…
- Question 8 – Delhi and Agra are 233 km apart. P travels from Delhi to Agra; Q starts from Agra to Delhi one hour later. They meet 75 minutes after Q starts. Both…
- Question 9 – A 44 matrix M=[m ij] has all diagonal entries zero and satisfies m ij=-m ji. What is the minimum number of elements needed to specify it?
- Question 10 – The chart shows profit percentages of companies P and Q during 2013–2018. Both invest a fixed, equal amount every year. Find the ratio of P’s total…
- Question 11 – Which method requires an initial interval bracketing a root to solve f(x) = 0 for a continuous nonlinear algebraic f?
- Question 12 – Match P: tanh x, Q: coth x, R: sech x, S: cosech x with I: (ex+e-x)/(ex-e-x); II: 2/(ex+e-x); III: 2/(ex-e-x); IV: (ex-e-x)/(ex+e-x).
- Question 13 – For v=3x2y i+8y2z j+5xyz k, find its curl.
- Question 14 – The unit step shown is zero for t < 3 and one for t ≥ 3. Its Laplace transform is
- Question 15 – For constant-pressure filtration with incompressible cake, a plot of t/V versus filtrate volume V is linear with intercept 104 s/m³. Filter area is…
- Question 16 – A unit tracer pulse enters a steady ideal plug-flow reactor with recycle ratio R = 1, defined as recycled volume divided by volume leaving the system.…
- Question 17 – The squared Thiele modulus is M T2=L2k/D eff for a first-order reaction in a porous catalyst. It measures the ratio of
- Question 18 – A hot-wire anemometer measures
- Question 19 – Pure gas P is absorbed into a liquid, where dissolved P undergoes an irreversible first-order reaction within the liquid film. Which graph shows its…
- Question 20 – An equimolar benzene–toluene mixture is batch distilled at atmospheric pressure. Benzene mole fraction in all distillate collected after 10 minutes is…
- Question 21 – Which statement is NOT correct?
- Question 22 – The Haber process at 350–500°C produces ammonia under which conditions?
- Question 23 – Match refinery processes P hydrodesulfurization, Q fluid catalytic cracking, R naphtha reforming to catalysts I zeolites, II Pt/Al₂O₃, III…
- Question 24 – Match P Solvay process, Q oxo process, R saponification to I: RCOOH + NaOH → RCOONa + H₂O; II: CH₂=CH₂ + CO + H₂ → CH₃CH₂CHO; III: CaCO₃ + 2NaCl →…
- Question 25 – A phenol plant produces 100 metric tons/year at full capacity. Selling price is INR 200/kg, production cost INR 50/kg, and annual fixed charges,…
- Question 26 – A rigid sphere of diameter 210-4 m and density 3000 kg/m³ settles freely in liquid of density 750 kg/m³ and viscosity 9.8110-3 Pa s. Assume Stokes law…
- Question 27 – A constant-property incompressible fluid flows parallel to a smooth thin wide flat plate at constant free-stream speed. Reynolds number at 2 m from…
- Question 28 – Momentum diffusivity divided by thermal diffusivity is the
- Question 29 – A binary liquid has mole fraction x₁ and activity coefficient γ₁ for component 1, and excess molar Gibbs energy Gᴱ. Which is always true?
- Question 30 – The Leidenfrost phenomenon refers to
- Question 31 – The irreversible gas reaction 2P → 4Q + R occurs in an isothermal isobaric batch reactor with ideal gases. Feed is equimolar P and an inert. Find the…
- Question 32 – Two Carnot engines operate in series between reservoirs R1→R2 and R2→R3 as shown. Their efficiencies are 0.40 and 0.35 respectively. If R1 is at 800…
- Question 33 – A negative unity-feedback loop has controller G c=0.2[1+1/(0.5s)] and process G p=10/[(s+1)(2s+1)] as shown. For a unit step in setpoint yₛₚ, find the…
- Question 34 – Acetaldehyde X decomposes through a four-step radical mechanism with overall rate -r X=k 2[k 1/(2k 3)]1/2C X3/2=k overallC X3/2. Elementary activation…
- Question 35 – Find the sum of eigenvalues of pmatrix2&4&6\\3&5&9\\12&1&7pmatrix, rounded to the nearest integer.
- Question 36 – A box contains 5 green and 10 blue balls. Six are drawn randomly without replacement. Find the probability of exactly four green and two blue.
- Question 37 – Find the maximum of f(x)=-(5/3)x3+10x2-15x+16 on (0.5,3.5).
- Question 38 – An isothermal countercurrent packed absorber removes SO₂ from air into pure water at constant pressure. Water rate is 2 kmol/s; inlet gas rate is 0.05…
- Question 39 – Two-film absorption has gas-side interfacial coefficient 0.1 mol/(m² s), liquid-side coefficient 3 mol/(m² s), and equilibrium y* = 2x, with gas and…
- Question 40 – The chart gives methanol–water equilibrium at 1 bar. A distillation column at 1 bar must produce 92 mol% methanol from an equimolar saturated-liquid…
- Question 41 – For ideal gases, N₂O₄ ⇌ 2NO₂ proceeds at 298 K and total pressure 1 bar. Standard reaction Gibbs energy is 5253 J/mol with pure ideal-gas standard…
- Question 42 – A well-mixed tank initially contains ideal gas with 21 mol% O₂ and 79 mol% N₂. Pure N₂ enters and gas exits, both at 8 mol/s. Temperature and pressure…
- Question 43 – An incompressible Newtonian fluid flows steadily and fully developed, laminar, through horizontal circular pipes I and II at the same volumetric rate.…
- Question 44 – The equilibrium curves show pressure-dependent azeotropic behaviour for components E and F. Feed is 80 mol% E, and 99.5 mol% E product is desired…
- Question 45 – A hollow cylinder of length L = D, its inner diameter, is sealed by flat end plates. Inner surfaces A₁ (top), A₂ (curved wall), A₃ (bottom) exchange…
- Question 46 – Fully developed laminar Bingham-plastic flow is in a tube of radius 0.01 m under a 10 kPa drop over length 1.0 m. The profile is flat for r < r꜀ and…
- Question 47 – Pure L enters the reactor–recycle process shown and partially converts to M. Recycle mass flow is 20% of product mass flow. Overall conversion of…
- Question 48 – The U-tube has manometric liquids of densities 1000 and 600 kg/m³. Initially both limbs are open to atmosphere and free levels differ by 10 cm as…
- Question 49 – A pure gas obeys PV/(RT)=1+BP/(RT), with molar V and constant B independent of T,P. Its residual Gibbs energy satisfies GR/(RT)= 0P(Z-1)dP/P at…
- Question 50 – One mole of ideal gas moves reversibly from L to N by two paths on the P–V diagram. Path I is straight LN. Path II follows horizontal LM, then…
- Question 51 – In a countercurrent double-pipe heat exchanger, cold fluid warms from 40°C to 60°C while hot fluid cools from 100°C to 70°C. Find LMTD in °C, to two…
- Question 52 – An infinitely long rectangular fin loses heat to fluid at Tₐ = 27°C. Its excess temperature θ = T − Tₐ obeys d2/dx2=m2, with m = 0.04 cm⁻¹ and base T₀…
- Question 53 – Water is pumped at 0.02 m³/s between the two open tanks shown. The receiving free surface is 5 m higher. Pipe friction loss is 1 m of water; surface…
- Question 54 – An elementary reversible liquid reaction P ⇌ Q occurs in an isothermal steady ideal CSTR with -r P=C P-0.5C Q mol/(L min). Feed contains only P at 1…
- Question 55 – A suspension at 60°C enters the first effect of a double-effect forward-feed evaporator at 1.25 kg/s. Combined water evaporation from both effects is…
- Question 56 – A vertical packed bed is 1 m high with void fraction 0.1 at no flow. Minimum fluidization is induced by fluid of density 1 kg/m³; solid density is…
- Question 57 – Two ideal cross-current extraction stages treat a feed of P and Q. Stage 1 receives P = 1000 kg/h and Q = 10000 kg/h; fresh pure solvent S enters…
- Question 58 – A fully developed falling water film on an impermeable wall is 1 m high and 10⁻⁴ m thick. Its thickness-averaged velocity is 0.01 m/s. Nonreactive gas…
- Question 59 – An exothermic first-order aqueous reaction Y → Z takes place adiabatically in a steady ideal CSTR. Rate is -r Y=109e-6500/TC Y mol/(L min), with T in…
- Question 60 – Two parallel irreversible liquid reactions P → Q and P → R have first-order constants k₁,k₂. An isothermal steady CSTR has space time 1 min,…
- Question 61 – A second-order catalytic gas reaction P → Q occurs isothermally and isobarically in a steady packed-bed reactor with ideal plug flow. Pure-P feed is 1…
- Question 62 – An equal-percentage valve passes 900 L/h at 30% opening and 1080 L/h at 35%, at constant pressure drop. Find flow at 45% opening in L/h, rounded to…
- Question 63 – A negative unity-feedback loop has proportional controller G꜀ = K꜀, final control element G f=10/(0.1s+1) and process G p=1/(0.1s+1)2. For gain margin…
- Question 64 – Given dy/dx = y − 20 with y(0) = 40, find y(2), rounded to the nearest integer.
- Question 65 – Tabulated x values are 1,3,5,15,25 with corresponding f(x) values 6,8,10,12,5. Use Simpson’s 1/3 rule to evaluate 125f(x)dx, rounded to one decimal…