Textile Engineering and Fibre Science
Textile Engineering and Fibre Science
Textile Engineering and Fibre Science
GATE 2021
Textile Engineering and Fibre Science
Question Paper & Answer Key
Textile Engineering and Fibre Science (TF)
Q.1 – Q.5 Multiple Choice Question (MCQ), carry ONE mark each (for each wrong
answer: – 1/3).
(A) 21
(B) 37
(C) 50
(D) 73
Q.2 A polygon is convex if, for every pair of points, P and Q belonging to the
polygon, the line segment PQ lies completely inside or on the polygon.
Which one of the following is NOT a convex polygon?
(A)
(B)
(C)
(D)
Q.4
A circular sheet of paper is folded along the lines in the directions shown.
The paper, after being punched in the final folded state as shown and
unfolded in the reverse order of folding, will look like _______.
(A)
(B)
(C)
(D)
Q. 6 – Q. 10 Multiple Choice Question (MCQ), carry TWO marks each (for each wrong
answer: – 2/3).
(A) 𝜋
2
(B) 3
𝜋
(C) 9
𝜋
(D) 3𝜋
Q.7
Items Cost Profit % Marked Price
(₹) (₹)
Q --- 25 10,000
Details of prices of two items P and Q are presented in the above table. The
ratio of cost of item P to cost of item Q is 3:4. Discount is calculated as the
difference between the marked price and the selling price. The profit
percentage is calculated as the ratio of the difference between selling price
𝐒𝐞𝐥𝐥𝐢𝐧𝐠 𝐩𝐫𝐢𝐜𝐞−𝐂𝐨𝐬𝐭
and cost, to the cost (𝐏𝐫𝐨𝐟𝐢𝐭 % = × 𝟏𝟎𝟎).
𝐂𝐨𝐬𝐭
The discount on item Q, as a percentage of its marked price, is ______
(A) 25
(B) 12.5
(C) 10
(D) 5
Q.8 There are five bags each containing identical sets of ten distinct chocolates.
One chocolate is picked from each bag.
The probability that at least two chocolates are identical is ___________
(A) 0.3024
(B) 0.4235
(C) 0.6976
(D) 0.8125
Q.9 Given below are two statements 1 and 2, and two conclusions I and II.
Statement 1: All bacteria are microorganisms.
Statement 2: All pathogens are microorganisms.
Conclusion I: Some pathogens are bacteria.
Conclusion II: All pathogens are not bacteria.
Based on the above statements and conclusions, which one of the following
options is logically CORRECT?
(A) The proposed AOM addresses the core problems that cause obesity.
(B) If obesity reduces, poverty will naturally reduce, since obesity causes poverty.
(C) AOM are addressing the core problems and are likely to succeed.
Q.1 – Q.13 Multiple Choice Question (MCQ), carry ONE mark each (for each wrong
answer: – 1/3).
(A) √2
(B) √3
(C) 0
(D) 1
(A) 1
(B) 2
(C) 3
(D) 4
Q.3 The smallest positive real number 𝝀, for which the following problem
𝒚′′ (𝒙) + 𝝀 𝒚(𝒙) = 𝟎,
𝒚′ (𝟎) = 𝟎, 𝒚(𝟏) = 𝟎
has non-zero solution, is
(A) 𝜋 2
(B) 𝜋 2
2
(C) 𝜋 2
4
(D) 𝜋 2
8
(A) Serine
(B) Fibroin
(C) Keratin
(D) Sericin
Q.6 The yarn manufacturing technology that uses perforated drums for twisting
is
Q.7 In roving frame, the distance between top and bottom aprons at the exit
point is maintained by
(A) Spacer
(B) Trumpet
(C) Condenser
(D) Pressure-bar
(A) Locknit
(A) Needlepunching
(B) Spunlacing
(C) Spunbonding
(D) Meltblowing
(C) U%
Q.12 The process for removal of protruding fibres from fabric surface is
(A) Desizing
(B) Scouring
(C) Souring
(D) Singeing
(C) Softener
Q.14 – Q.25 Numerical Answer Type (NAT), carry ONE mark each (no negative
marks).
Q.14 𝟏
Suppose 𝒖(𝒙, 𝒕) = 𝟐 [𝒈(𝒙 + 𝒄𝒕) + 𝒈(𝒙 − 𝒄𝒕)] is a solution of the following
initial value problem of the wave equation
𝒖𝒕𝒕 = 𝟗 𝒖𝒙𝒙 , 𝒖(𝒙, 𝟎) = 𝒈(𝒙), 𝒖𝒕 (𝒙, 𝟎) = 𝟎.
Then the value of 𝒄𝟐 is _____________.
Q.16 Assuming the atomic mass of H=1, C=12, N=14 and O=16, the molecular
mass of a repeat unit of Nylon 6 fibre is _________________.
Q.17 A textile filament records a tensile stress of 0.3 GPa at a tensile strain of 0.04.
Assuming Hookean behavior, the tensile modulus (GPa) of the filament,
(rounded off to one decimal place), is _______________.
Q.18 Number of fibres, each of 40 mm length and 0.16 tex fineness, in a tuft of 24
mg mass is _____________.
Q.19 Twist (turns per inch) of a cotton yarn of 36 Ne count produced with a twist
multiplier of 3.5 inch−1·Ne−0.5 is ______________.
Q.20 In winding, if traverse speed and package surface speed are the same, the
angle of wind (in degree) is _______________.
Q.21 During air-jet weft insertion, if the diameter of the yarn increases by 20 %
then the percentage increase in drag force acting on the yarn would be
_____________.
Q.22 If the ratio of the linear densities (denier) of two circular fibers is 3, the
corresponding ratio of their diameters, (rounded off to two decimal places), is
______________.
Q.23 If the sample size (n) is 25 and the standard deviation () of population is 2,
then the standard error (SE) of sample mean, (rounded off to one decimal
place), is _____________.
Q.24 The wet expression for a padding mangle is set at 80 %. If the add-on of a
flame retardant chemical required on the fabric is 2 % then the
concentration (g/L) of the chemical in the pad bath is _______________.
Q.25 Assuming Beer-Lambert law is applicable for dilute solutions, if the molar
concentration of dye in the solution is doubled then the percentage increase
in absorbance would be ______________.
Q.26 – Q.41 Multiple Choice Question (MCQ), carry TWO mark each (for each wrong
answer: – 2/3).
(A) 6
(B) 4
(C) 3
(D) 2
Q.28 Determine the correctness or otherwise of the following Assertion [a] and
Reason [r]
Assertion: Draw texturing of isotactic polypropylene (POY) at a relatively
high speed is possible despite high crystallinity of the feeder yarn.
Reason: Isotactic polypropylene (POY) has majorly smectic mesomorphic
phase.
(A) Both [a] and [r] are true and [r] is the correct reason for [a]
(B) Both [a] and [r] are true but [r] is not the correct reason for [a]
Q.29 Group I gives a list of fibres and Group II contains their applications. Match
the fibre with its application.
Group I Group II
P. Polypropylene 1. Mountaineering rope
Q. Kevlar 2. Firefighter’s suit
R. Nylon 6, 6 3. Bulletproof jacket
S. Nomex 4. Geotextiles
Q.30 Techniques used for determination of orientation in fibres from amongst the
followings are
P Birefringence measurement
Q Scanning electron microscopy
R X-ray diffraction
S Differential scanning calorimetry
(A) P and Q
(B) P and R
(C) Q and R
(D) Q and S
Q.33 Assuming no fibre loss in draw frame, if draft is equal to doubling then the
delivered sliver, as compared to fed sliver, will exhibit
Q.34 Group I gives a list of loom motions and Group II contains loom systems.
Match the motion from Group I with the corresponding system from Group
II.
Group I Group II
P. Shedding 1. Matched cam
Q. Picking 2. Seven wheel
R. Beat-up 3. Rapier
S. Take-up 4. Jacquard
Q.35 Group I gives a list of terms related to woven fabrics and Group II contains
equivalent terms related to knitted fabrics. Match the term from Group I
with the equivalent term from Group II.
Group I Group II
P. Cover 1. Interlock
Q. Double-cloth 2. Wales
R. Warp 3. Tightness
S. Weft 4. Courses
Q.36 Determine the correctness or otherwise of the following Assertion [a] and
Reason [r]
Assertion: In shuttle loom, late shedding is preferred for filament weaving.
Reason: In late shedding, the timing of shed dwell matches with the timing
of shuttle travel through the shed, and therefore, it minimises the rubbing of
warp yarns.
(A) Both [a] and [r] are true and [r] is the correct reason for [a]
(B) Both [a] and [r] are true and [r] is not the correct reason for [a]
Q.37 The typical shapes of comb sorter diagram and fibrogram of polyester fibres
of equal cut length will be
Q.38 In Classimat system, the yarn fault H2, as compared to yarn fault C3, is
Q.39 Determine the correctness or otherwise of the following Assertion [a] and
Reason [r]
Assertion: Application of an optical brightening agent makes the white
fabrics appear brighter.
Reason: Optical brightening agents absorb energy in the visible region and
radiate back in the UV region.
(A) Both [a] and [r] are true and [r] is the correct reason for [a]
(B) Both [a] and [r] are true and [r] is not the correct reason for [a]
Q.40 Determine the correctness or otherwise of the following Assertion [a] and
Reason [r]
Assertion: Nylon is dyed with acid dyes in the acidic medium.
Reason: Nylon assumes positive charge in the acidic medium and thus,
attracts the negatively charged acid dye molecules.
(A) Both [a] and [r] are true and [r] is the correct reason for [a]
(B) Both [a] and [r] are true and [r] is not the correct reason for [a]
Q.41 Determine the correctness or otherwise of the following Assertion [a] and
Reason [r]
Assertion: Discharge printing of dyed polyester fabric is not possible.
Reason: The discharging agents damage the polyester fibres significantly.
(A) Both [a] and [r] are true and [r] is the correct reason for [a]
(B) Both [a] and [r] are true and [r] is not the correct reason for [a]
Q.44 In melt spinning, the mass throughput rate of polymer is 210 g/min, the
winding speed is 3000 m/min, and the linear density of the yarn produced is
200 denier. The effective draw ratio, (rounded off to two decimal places), is
______________.
Q.48 For a given woven fabric, fractional cover is 0.5 for both warp and weft. The
fractional cover of the fabric, (rounded off to two decimal places), is
_______________.
Q.49 For a shuttle loom, producing plain woven fabric, if each of the dwell periods
of the shedding cam corresponds to one-third of crank shaft rotation, the
sum of the two dwell periods of the cam (in degree) is _______________.
Q.50 If the moisture regain (%) and moisture content (%) of a fibre are the same
then the value of moisture regain (%) is ________________.
Q.51 Mass of 120 yards of cotton yarn is 3 g. The count (Ne) of yarn, (rounded off
to one decimal place), is _______________.
Q.52 A woven fabric with areal density of 300 g/m2 is tested by strip tensile test
method, keeping the specimen width as 5 cm and gauge length as 25 cm. If
the breaking load is 900 N, the tenacity (cN/tex) of the fabric is
_____________.
Q.53 A 50 tex yarn with mass CV of 12.5 % is produced from staple polyester
fibres each of 4.5 denier fineness. The index of irregularity of the yarn,
(rounded off to two decimal places), is ______________.
Q.55 Consider the following isotherms at equilibrium for two disperse dyes D 1
and D2 dyed on polyester. If the partition coefficients of these are K1 and K2,
𝑲𝟐
respectively, the value of is _______________.
𝑲𝟏
1 5 MCQ GA C 1 1/3
2 5 MCQ GA A 1 1/3
3 5 MCQ GA C 1 1/3
4 5 MCQ GA A 1 1/3
5 5 MCQ GA C 1 1/3
6 5 MCQ GA C 2 2/3
7 5 MCQ GA C 2 2/3
8 5 MCQ GA C 2 2/3
9 5 MCQ GA C OR D 2 2/3
10 5 MCQ GA D 2 2/3
1 5 MCQ TF B 1 1/3
2 5 MCQ TF C 1 1/3
3 5 MCQ TF C 1 1/3
4 5 MCQ TF D 1 1/3
5 5 MCQ TF B 1 1/3
6 5 MCQ TF C 1 1/3
7 5 MCQ TF A 1 1/3
8 5 MCQ TF D 1 1/3
9 5 MCQ TF B 1 1/3
10 5 MCQ TF A 1 1/3
GATE 2021 Answer Key for Textitle Engineering and Fibre Science (TF)
11 5 MCQ TF B 1 1/3
12 5 MCQ TF D 1 1/3
13 5 MCQ TF A 1 1/3
14 5 NAT TF 9 to 9 1 0
19 5 NAT TF 21 to 21 1 0
20 5 NAT TF 45 to 45 1 0
21 5 NAT TF 20 to 20 1 0
24 5 NAT TF 25 to 25 1 0
26 5 MCQ TF A 2 2/3
27 5 MCQ TF D 2 2/3
28 5 MCQ TF A 2 2/3
29 5 MCQ TF B 2 2/3
30 5 MCQ TF B 2 2/3
31 5 MCQ TF D 2 2/3
32 5 MCQ TF A 2 2/3
33 5 MCQ TF C 2 2/3
GATE 2021 Answer Key for Textitle Engineering and Fibre Science (TF)
34 5 MCQ TF C 2 2/3
35 5 MCQ TF B 2 2/3
36 5 MCQ TF A 2 2/3
37 5 MCQ TF B 2 2/3
38 5 MCQ TF C 2 2/3
39 5 MCQ TF D 2 2/3
40 5 MCQ TF A 2 2/3
41 5 MCQ TF C 2 2/3
42 5 NAT TF 5 to 5 2 0
43 5 NAT TF 28 to 28 2 0
50 5 NAT TF 0 to 0 2 0
52 5 NAT TF 6 to 6 2 0