# GATE (TF) Textile 2021 Question Paper Solution | GATE/2021/TF/10

###### Question 10 (Textile Technology & Fibre Science)

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Uniformity index is used to measure variation in cotton fibre length and limiting irregularity is minimum count variation expected from ideal yarn with a random fibre ends distribution.
Index of irregularity is the ratio of CV effective and CV limit.
The irregularity U% is proportional to intensity of the mass variation around mean value.

### What is uniformity index ?

The uniformity index is a measure of the variation in fiber or yarn diameter. It is calculated by dividing the mean fiber or yarn diameter by the standard deviation of the diameter measurements. The higher the uniformity index, the more uniform or even the fibers or yarn are in diameter.

### What is U% ?

U% is a measure of the variation in fiber or yarn weight per unit length. It is calculated by dividing the difference between the maximum and minimum weight per unit length by the mean weight per unit length, and multiplying by 100. The higher the U%, the greater the variation in weight per unit length and the less uniform or even the fibers or yarn are.

### What is index of irregularity ?

The index of irregularity is a measure of the variation in fiber or yarn diameter along its length. It is calculated by dividing the difference between the maximum and minimum diameter by the mean diameter, and multiplying by 100. The higher the index of irregularity, the more irregular or uneven the fiber or yarn is in diameter along its length.