sample questions for practice fiber length

8/13/2019 Sample Questions for Practice Fiber Length

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Textile Testing

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Question Bank

A. Multiple Choice (1 Answer)

1. A high percentage of short fibers is usually associated witha. Higher wastage in Combingb. Higher wastage in Blowroomc. Higher wastage in Cardingd. Higher wastage in Drawframe

2. Fibrograph is used to obtain (2005)a. average fibre lengthb. fibre finenessc. span lengthd. short fibre percentage

3. Fibrograph uses an optical method of measuring the _____ along the length ofa tuft of parallel fibers

a. weightb. densityc. finenessd. strength

4. Fibrograph works ona. manual systemb. capacitive sensorsc. laser technologyd. photoelectric cells


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5. As a general rule the longer wools are _______ than the shorter ones and in thecase of cotton the longer fibres are _________ than the short ones

a. coarser; finerb. coarser; coarserc. finer; finerd. finer; coarser

6. As per the sorter diagram, percentage short fibers isa. less than half the effective lengthb. less than half the span lengthc. less than half maximum lengthd. less than half average or mean length

7. In case of fibrograph, __________________ approximates to the staple lengtha. upper half mean lengthb. lower half mean lengthc. mean lengthd. uniformity ratio

8. In case of wool, short fibers are the fibers having length less thana. < 10 mmb. 10 - 20 mmc. 25 - 40 mmd. > 40 mm


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9. Short fiber content relates directly to the amount of waste extracted in ______a. Blowroomb. Cardingc. Drawframed. Combing

10.In case of Cotton, Short fibers are the fibers having length less than___a. 12 mmb. 12.5 mmc. 12.7 mmd. 12.9 mm

11.Short fibre content measured by the ______ is referred to as short fibre index(SFI)

a. Fibrogramb. AFISc. HVId. Peyer Almeter

12.Staple length is approximately equal toa. effective lengthb. short lengthc. maximum lengthd. modal length


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13.The 2.5% span length is numerically nearer to (1999)a. Staple lengthb. Mean lengthc. Short fibre%d. Longest fibre length

14.The amount of ___________ present influences the amount of noil or wasteextracted

a. long fiberb. short fiberc. mean length fiberd. modal length fiber

15.The length of the main bulk of the longer fibers is known asa. effective lengthb. modal lengthc. average or mean lengthd. maximum length

16.In case of Cotton,Short fibers are the fibers having length less thana. 1 inchb. 3/4 inchc. 1/2 inchd. 1/4 inch


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17.The percentage range of the uniformity ratio for cotton fibres in general is(2006)

a. 40-50b. 55-65c. 70-80d. 85-95

18.The setting of the distances between the nips of successive pairs of draftingrollers is depends on

a. span lengthb. effective lengthc. maximum lengthd. modal length

19.The term __________ is not used when analyzing the comb sorter diagrama. span lengthb. effective lenghtc. staple lengthd. short length

20.Uniformity Index normal cotton is in the range ofa. 55-65%b. 65-75%c. 75-85%d. 85-95%


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21.Uniformity ratio (%) of cotton is in the range of (2007)a. 40-50b. 60-70c. 80-90d. 90-100

22.WIRA fiber length machine is designed to measure the fiber length ofa. single cotton fiberb. cotton sliverc. single wool fiberd. wool sliver

23.WIRA fibre diagram machine works ona. capacitance principleb. optical principlec. manual methodd. photoelectric cell principle

24.Fiber length is the most important fibre properties required by ________ toprocess high quality yarns

a. Rotor spinningb. DREF Spinningc. Air jet Spinningd. Wrap spinning


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25.Uniformity ratio is the ratio of (2008)a. 50% span length and 2.5% span lengthb. 2.5% span length and 50% span lengthc. Mean length and upper half mean lengthd. Upper half mean length and mean length

26.WIRA fibre diagram machine is designed to measure the fibre length ofa. combed wool sliverb. single wool fiberc. single cotton fiberd. combed cotton sliver

27.With staple fibers, the individual fiber length is ______ important than thedistribution of fiber lengths in a sample of fibers

a. moreb. lessc. notd. extremely

28.Uniformity ratio of fibres of equal length is approximately equal to (2005)a. 0.51b. 0.71c. 0.91d. 1.00


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Textile Testing

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29.Uniformity ratio for normal variety of cotton is in the range (2009)a. 0.2-0.3b. 0.4-0.5c. 0.7-0.8d. 0.9-1.0

30.Uniformity Ratio gives an idea about (1998)a. Short fibre percent in cottonb. Effective length of cottonc. Length variability of cottond. Longest fibre present in cotton

31.Proportion of short fibre does not influence________ spinninga. Ringb. Air jetc. Rotord. DREF

32.The 1% and 2.5% span length are lengths that are needed for________a. Roller space settingb. Yarn Twistingc. Comber noild. Fine yarn


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33.Large proportion of short fibers also leads to considerable fly contamination &put strain

a. on personnelb. on machinesc. on the air-conditioningd. above all

34.In case of __________, fibre weight per unit length is not constant but varieswith the fibre length

a. Cottonb. Flaxc. Woold. Silk

35.The measurement of fibre length is mainly used for thea. Assessment of raw materialsb. To see the effect on processingc. To determine the efficiency of combing processd. All of above

36.Subjective evaluation of the fibre length is done with the help ofa. Comb sorterb. Hand staplingc. Single fibre measurementd. Fibrograph


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37.________________is a characteristic of the bulk of the longer fibresa. Effective lengthb. Mean lengthc. Maximum lengthd. Modal length

38.In case of effective length, which of the following statement is not TRUEa. Short fibres are ignored while finding itb. It reduced the initial rapid change in length from maximumc. It is sum of base line readings divided by base line lengthd. Spinning Machine settings are related to it

39.Normally, cotton fiber gives the ________________ shape of comb sortera. Rectangular stapleb. Triangular staplec. Trapezoidal stapled. Stepped staple

40.Which types of comb sort diagram represent more number of short fibres?a. Rectangular stapleb. Triangular staplec. Trapezoidal stapled. Stepped staple


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41.Fibrogram is produced bya. Comb sorterb. HVIc. AFISd. USTER Stapling

42.For the measuring the fibre length, which principle is used by indirectinstrumental method

a. thickness gaugeb. photoelectric optical systemc. electrical capacitor platesd. All above

43.USTER stapler use the _____________ method to measure the fibre lengtha. Thickness gauge (Pneumatic Pressure)b. Opticalc. Capacitanced. Photoelectric

44.It is important that in addition to the fibre length of a cotton, the degree ofirregularity of its length should also be known

a. Short fibre percentage is same in the fibre having different mean lengthb. Short fibre percentage is different in the fibre having same mean lengthc. Short fibre percentage is different in the fibre having different mean

length

d. Short fibre percentage is same in the fibre having same mean length


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45.Length uniformity index of cotton fiber will always bea. 100b. More than 100c. Less than 100d. ZERO

46.Cotton with the low uniformity index is likely to produce low quality yarnbecause

a. Low percentage of short fibreb. High percentage of short fibrec. High percentage of long fibred. Equal length of fibre

47.An increase of ______ in fibre length increases yarn strength approx. by 0.4cN/tex or more

a. 1 mmb. 4 mmc. 0.1 mmd. 0.4 mm

48.A fibre length __________ is desirable in most cases, although this dependsupon the spinning system and yarn count.

a. above 28 mmb. less than 28 mmc. equal to 28 mmd. 12. 7 mm


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49.An increase of 1% (absolute) in Short Fibre Content can decrease ring spun yarnstrength by_______________

a. Less than 1%b. 1% or morec. Equal to 1%d. 0%

50.Low length uniformity _____________ unevenness and _______________ thestrength of the yarn

a. Increases; decreasesb. Increases; increasesc. Decreases; increasesd. Decreases; decreases

51.Long cotton fibre are generally more prone to forming neps during_________a. Blow roomb. Cardingc. Draw framed. Combing

52.Long cotton fibre often carded at ______________a. Higher speedb. Lower speedc. Medium speedd. Regular speed


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53.For processing of Longer fiber, carding speed need to be____________ andring spinning speed need to be____________

a. Increased; increasedb. Increased; decreasedc. Decreased; increasedd. Decreased; decreased

54.The inverse of length uniformity also provides a measure of _______________a. Mean lengthb. Span lengthc. CV of lengthd. Floating fiber

55.Short Fibre Content defined by ________ is considered a more sensitivemeasure of processing conditions

a. Weightb. Numberc. Percentaged. Ratio

56.A uniformity index of above ___ % and uniformity ratio above ____% aredesirable

a. 83; 48b. 48; 83c. 83; 83d. 48; 48


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57.All fiber-length testing instruments require a minimum of ____ gms of ginnedfibers

a. 1b. 2c. 5d. 10

58.Fiber length is the most important fibre properties required by ________ toprocess high quality yarns

a. Ring spinningb. Rotor spinningc. DREF Spinningd. Wrap spinning

59.By the keeping the same level twist, if longer fibres are used to produce theyarn then it will result in

a. Finer countb. Higher yarn strengthc. Softer yarnd. No change

60.Fibre length __________ mm will only produce the positive characteristics inthe yarn

a. Above 15 mmb. Between 12 15 mmc. Below 12 mmd. Above 5 mm


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B. Multiple Choice (Multiple Answers, either 2 or 3)

1. A high percentage of short fibers is usually associated witha. Increase in yarn irregularity and ends downb. Increase numbers of neps and slubsc. Higher wastage in combingd. Higher wastage in blowroom

2. During length measurement on Fibrograph,2.5% span length was found to be25 mm. It means (1992)

a. 2.5% of fibres clamped are 25 mm is lengthb. 2.5% of fibres clamped are longer than 25 mmc. 2.5% of fibres clamped are 25 mm or longerd. 2.5% of fibres clamped are less than 25 mm

3. More number of short fibres results ina. Unevenness in yarnb. More waste generationc. Soft twisted yarnd. Yarn hairiness

4. Fibrograph normally measures the..a. mean lengthb. short lengthc. modal lengthd. span length


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5. Effective length isa. length of the main bulk of the longer fibersb. upper quartile of the fiber length distributionc. read directly from the sorter diagramd. the length on which many machinery settings are related

6. From the point of view of cloth characteristics, however, short fibres have theadvantage where it is desirable to produce

a. soft surfaceb. rough surfacec. hairyd. warm handling

7. Crimp in the fiber can be measured asa. waves per unit lengthb. crimp anglec. % increase in extent of the fibre on removal of the crimpd. fiber length

8. Crimp, the waviness of a fiber, is important and desired becausea. determines the cohesiveness of card websb. the amount of fly liberated during processingc. it reduces the effective length of the fiberd. the hairiness of the resultant yarn


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9. Determination of fiber length by using photoelectric cells principle is done withthe help of

a. Fibrographb. HVIc. AFISd. Digital Fibrograph

10.Mean length of the fiber can be deriveda. based on number of fibresb. based on fibre cross-sectionc. based on fibre massd. based on fiber strength

11.The main advantages of longer fibers area. easier to processb. more even yarn can be producedc. higher strength yarn can be producedd. cheaper

12.The main disadvantages of hand stapling over instrumental method of fiberlength testing are

a. it is time consumingb. it is simple and easyc. short fibers are discountedd. variation in density (numbers of fibers) of hand prepared tuft


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13.The staple length of the cotton is in betweena. mean lengthb. short lengthc. maximum lengthd. effective length

14.Variations in fibre length can cause severe problems and lead toa. increase in wasteb. deterioration in processing performancec. yarn qualityd. shade variation in fabric

15.Fibre length influencesa. lusterb. yarn hairinessc. productivityd. varying Dyeablity

16.The fibre length property is usefula. to decide draft amountb. to decide machine setting in spinningc. to calculate combing efficiencyd. to study breakage rate during processing


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17.The proportion of short fibers has increased substantially in recent years mainlybecause of

a. atmosphereb. waterc. mechanical pickingd. hard ginning

18.Staple length is approximately equal toa. Effective lengthb. Modal lengthc. Mean lengthd. Maximum Length

19.In case of effective length, which of the following statements are TRUEa. Short fibres are ignored while finding itb. It reduced the initial rapid change in length from maximumc. It is sum of base line readings divided by base line lengthd. Spinning Machine settings are related to it

20.The major disadvantages of hand stapling area. It consider the short fibreb. It ignore the fibre extentc. Variation in tuft densityd. Time consuming


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21.The problems with the equal length fibres area. It is difficult to maintain fibre length evenness in yarnb. Spinning machines are not suitable to process itc. Create high degree of unevenness in yarnd. Loss in yarn strength

22.For the measuring the fibre length, which principle are used by indirectinstrumental method

a. thickness gaugeb. photoelectric optical systemc. electrical capacitor platesd. manual observations

23.Measurement of fibre extent is more desirable as compare to measuring thelength of straight fibre because

a. Fibres are not straight at the time of processingb. Fibres are not straight at the time of usingc. Fibres are not aligning along a common line in processingd. Fibres are straight at the time of using

24.Fibre length variation can be denoted by one of the followinga. CV of length (by weight or number)b. Irregularity percentagec. Percentage of short fibresd. Span length


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25.Longer fiber enablesa. Carded at low speedb. Low roving twistc. Higher ring spinning speedd. High yarn twist

26.Normally, short fibre content is defined bya. Weightb. Percentagec. Ratiod. Numbers

27.Short fibre content depends upona. Genotypeb. Harvestingc. Ginningd. Blow room

28.Fiber length is the most important fibre properties required by which spinningsystem to process high quality yarns

e. Ring spinningf. Rotor spinningg. DREF spinningh. Air Jet spinning


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29.The main advantage of WIRA Fibre Length Machine isa. it gives a standard tension to the fibresb. it involves less operator fatiguec. it gives semi-automatic recording of the resultsd. it works on the tuft method


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C. State True or False

Sr No Statement True or False

1 As wool fibres are relatively long, length is a less important property

2 Comb sorters can be used for card slivers

3 In case of cotton fiber, the length and fineness are directly proportional

to each other

4 In case of wool, longer the fiber, finer it will be

5 Longer lengths fibers contribute to the tenacity of yarn by increasing the

frictional forces with adjacent fibers

6 Staple length is closely related with the roller setting in drafting

7 Longer lengths of cotton fiber contribute to the tenacity of yarn via

increased frictional forces with adjacent fibers

8 The longer the fibre length, the lower is the end breakage rate

9 UHML is the mean length by numbers of the longer half (50%) of the

fibre by weight

10 Fibres upto about 12 - 15 mm do not contribute to strength but only to

fullness of the yarn

11 In case of natural fibre, length and fineness are related to each other

12 Fibre length determines the draft settings of machines

in a spinning mill

13 Short fibre contribute to the yarn strength

14 Most of the time, the cut length of manmade fibres is influenced by the

fibre length of natural fibres

15 Fibre length is very useful in calculating the combing efficiency

16 Fibre length is not correlated with fabric strength

17 After carding, Fibre length does not plays important role


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18 In case of Longer cotton fiber, more twist need to be inserted in to yarn

19 The 1% and 2.5% span length are lengths that are needed in setting

machines, especially roller spacings

20 Large proportion of short fibers puts lots of strain on personnel by fly

contamination

21 Fibre length is not useful to study the breakage rate during spinning

22 More number of short fibres creates problem in drafting

23 Fibres are never straight in use

24 Longer fibres give better spinning performance than shorter ones

25 Spinning machines are not suited to the processing of fibers having all

the same length

26 No variation in fibre length can produce a high degree of unevenness in

the yarn

27 In case of Manmade fibre, length and fineness cannot be controlled

separately

28 In case of wool, fibre weight per unit length is not constant but varies

with the fibre length

29 Cotton grader uses objective assessment system to measure staple

length by hand stapling method

30 In case of natural fibre, fiber length exhibits the greatest irregularity of allthe fiber characteristics

31 More number of short fibre are not problematic for air conditioners in

spinning mill

32 In comb sorter, basically, the fibres are sorted in the length group

33 Staple diagram is equivalent to a graph of length against cumulative

frequency

34 Effective length is a characteristic of the bulk of the longer fibres


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35 The distances between the nips of successive pairs of the drafting rollers

is depend on effective length

36 Short fibres are considered while finding the effective length on comb

sorter diagram

37 One of the drawback of comb sorter is that it ignored the fiber extent

38 Weight based sort diagram has a notably higher curve compared with

the numerical diagram, because long fibers have more mass than short

fibers and therefore a greater effect

39 The weight-based comb sorter diagram corresponds to the distribution

of fibers in the yarn cross-section

40 In case of natural fibre, rectangular shaped sorter diagram is possible

41 Ideal fibers should be of equal length and without any length variations

42 The Fibrogram corresponds to the arrangement of fibers at the nip line

of rollers

43 Measurement of fibre extent is more desirable as compare to measuring

the length of straight fibre

44 USTER stapler use the thickness gauge method

45 Fibrograph works on capacitance principle

46 In fibrograph, longer fibres has greater chance to get catch

47 The term span length is used in when analyzing the comb sorter diagram

48 2.5% span length is considered to correlate with the classers staple

length

49 Cotton fibre having nearly the same mean fibre length can have different

percentage of short fibre

50 Dispersion percentage is one the method to express fibre length

variation

51 Length uniformity index of cotton fiber will always be less than 100


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52 Cotton with a low uniformity index is likely to have a low percentage of

short fibers

53 An increase of 1 mm in fibre length increases yarn strength approx. by

0.4 cN/tex or more

54 A fibre length above 28 mm is desirable in most cases, although this

depends upon the spinning system and yarn count.

55 50% span length represent the mean length of fibre

56 An increase of 1% (absolute) in Short Fibre Content can decrease ring

spun yarn strength by 1% or more

57 Long cotton fibre are generally more prone to forming neps during

carding

58 Longer fiber require more amount of twist during roving and yarn

manufacturing

59 Ring spinning speed need to be high for the long fibre

60 The short fibre content (SFC) is a better indicator of the floating fibres

61 Short Fibre Content defined by weight is considered a more sensitive

measure of processing conditions

62 Fabric strength and abrasion resistance also tend to deteriorate with an

increase in SFC

63 An SFC below 8% (by weight) is desirable64 The uniformity ratio is expressed as a percentage of the longer length

65 Fibre is the most property which need to be considered at the time of

rotor spinning

66 If fiber materials of very different lengths are blended in the wrong

proportions, then a stepped staple curve can formed

67 WIRA fibre diagram machines is designed to measure single fibre length

68 In testing of wool fibre, the application of standard tension is important

sample questions for practice fiber length

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