GATE MT format:nat PYQs & Answers — Page 3

Questions 21–30 of 232. Imported answers require independent review unless marked reviewed.

Topic practice 232 questionsPage 3 of 24

During carburizing of a steel, the surface concentration is kept constant at 1.4 wt.% carbon. Diffusivity of carbon for the steel at 950 °C is 6.25 × 10⁻¹¹ m²/s. At 950 °C, the time required to carburize the steel with an initial composition of 0.2 wt.% carbon to 0.859 wt.% carbon at a depth of 0.2 mm is ______________ seconds (approximate to the nearest integer).

Use the nearest value of the error function from the table given below for your calculation.

z	erf (z)
0.3	0.3268
0.4	0.4284
0.5	0.5205

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For the following reaction between methane and stoichiometric air having composition 20 vol.% O₂ and 80 vol.% N₂, the estimated adiabatic flame temperature (rounded off to one decimal place) is _________________ Kelvin.

CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O (g)

Given: ΔH = − 850 kJ/mol at 298 K

Assume specific heat at constant pressure (Cₚ) for each reactant and product is 50 J/mol-K and is independent of temperature.

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A copper ore contains 30 wt.% chalcopyrite (CuFeS₂) and remaining gangue material. Assuming no copper in gangue material, the amount of copper in the ore (rounded off to one decimal place) is __________ wt.%. Given: Atomic weights of Fe, Cu and S are 56, 63.5, and 32 g/mol, respectively.

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A blast furnace produces hot metal with the following composition: 4 wt.% C, 1.5 wt.% Si, and rest Fe.

Only input of iron is through iron ore containing 85 wt.% Fe₂O₃ and 15 wt.% gangue consisting of SiO₂ and Al₂O₃.

2% of all iron (by weight) is lost in slag.

The amount of ore used to produce 1000 kg of hot metal (rounded off to one decimal place) is __________ kg.

Given: Atomic weights of Fe and O are 56 g/mol and 16 g/mol, respectively.

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Al₂O₃ can be electrolyzed with an inert anode or a carbon anode.

Overall reactions are as follows:

Reaction I: For inert anode,

Reaction II: For carbon anode,

T denotes temperature in Kelvin

Given: Faraday constant = 96500 Coulomb

If inert anode is replaced by carbon anode during electrolysis of Al₂O₃ at temperature 1300 K, the decrease in the magnitude of decomposition potential between the two reactions (rounded off to two decimal places) is __________ Volts.

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Given a scalar field

Magnitude of a vector in the direction of the most rapid increase of

at a point P (3,4,1), rounded off to two decimal places, is __________

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The hydrostatic stress for the stress tensor provided below is _____ MPa (in integer).

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For an application where the Reynolds number is to be kept constant, a liquid with a density of 1 g cm

and viscosity 0.01 Poise results in a characteristic speed of 1 cm s

. If this liquid is replaced by another with a density of 1.25 g cm

and viscosity of 0.015 Poise, the characteristic velocity will be _____ cm s

(rounded off to one decimal place). Assume the characteristic length of the flow to be the same in both cases.

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Consider the gas phase reaction:

At equilibrium for a particular temperature, the partial pressures of CO, O

, and CO

are found to be

atm,

atm, and 16 atm, respectively. The equilibrium constant for the reaction is _____

(rounded off to one decimal place).

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A linear regression model was fitted to a set of

data. The total sum of squares and sum of squares of error are 120 and 12, respectively. The coefficient of determination (

) of the fit is _____ (rounded off to one decimal place).

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GATE MT format:nat PYQs

Question 60

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Question 63

Question 64

Question 65

Question 32

Question 33

Question 34

Question 35