GATE XE branch:xe PYQs & Answers — Page 138

Questions 1371–1380 of 1772. Imported answers require independent review unless marked reviewed.

Match the material classification in Column A with the appropriate one in Column B: (PS=polystyrene, PPO=polyphenylene oxide, PDMS=poly(dimethyl siloxane), PP=polypropylene, PE=polyethylene, PP-g-MA=maleic anhydride grafted PP)

Column A P. Miscible blend Q. Immiscible blend R. Compatibilized blend S. Polymer composite

Column B

PDMS + fumed silica

Nylon 6 + PP-g-MA + PP

PS + PPO

PE + PP

Your answerChoose one option.

P-3, Q-4, R-2, S-1

P-4, Q-3, R-2, S-1

P-3, Q-4, R-1, S-2

P-4, Q-3, R-1, S-2

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A linear amorphous polymer has a T_g of +10 °C. At 28 °C, it has a melt viscosity of 4 × 10⁸ poise. The viscosity of the polymer at its T_g is ______ × 10¹³ poise (round off to one decimal place).

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A polypropylene (PP) bar with a 10 mm × 10 mm square section is 225 mm long. The modulus of PP bar is 861 MN m⁻². It is pinned at both ends and an axial compressive load of 140 N is applied. The strain due to the applied load experienced by the PP bar is ____ % (round off to two decimal places).

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In a unidirectional carbon fibre/vinyl ester composite, the ratio of the moduli of the carbon fibre to that of vinyl ester is 35 and the fibres take up 50% of the cross-section. The percentage of applied force taken up by the fibres is ______ % (round off to one decimal place).

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A 3 mm thick layer of softened poly(methyl methacrylate) at 190 °C is sandwiched between two flat parallel plates. A shear stress of 100 kPa is applied to the softened polymer. Assuming the softened polymer as a Newtonian fluid with an apparent viscosity of 3.9 × 10⁴ Pa s, the relative sliding velocity between the two plates is ____ mm s⁻¹ (round off to one decimal place).

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For ABN initiated polymerization of styrene, if both the monomer and initiator concentration are doubled, then the rate of polymerization increases by a factor of ______ (round off to two decimal places).

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If 49 moles of hexamethylene diamine is reacted with 50 moles of adipic acid to prepare Nylon 66, then the number average molecular weight, M̅_n of the resulting polymer at 99.5% conversion (ignoring contribution from end groups) is ______ g mol⁻¹ (round off to 2 decimal places).

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A single screw extruder is to be used to manufacture a nylon rod of 0.5 cm diameter at a production rate of 2.5 cm s⁻¹. The density of solid nylon and nylon melt are 1.140 g cm⁻³ and 0.790 g cm⁻³, respectively. The melt flow rate through the die is ______ cm³ s⁻¹ (round off to two decimal places).

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Colloid stability of milk casein is because of the highly hydrated carbohydrate residues in ________.

Your answerChoose one option.

αₛ₁ casein

αₛ₂ casein

β casein

κ casein

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Rice bran is stabilized prior to oil extraction to protect it from the activity of ________.

Your answerChoose one option.

Polyphenol oxidase

Peroxidase

Lipase

Lipoxygenase

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GATE XE branch:xe PYQs

Question 15

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Question 19

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Question 22

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