Question

Select the correct match 

• A. I-ii, II-i, III-iii, IV-iv
• B. I-i, II-ii, III-iii, IV-iv
• C. I-i II-ii, III-iv, IV-iii
• D. I-ii, II-i, III-iv, IV-iii

Hint:

Matching questions require understanding the specific characteristics of each yarn type and spinning system. DREF = core-sheath; Rotor = open-end, doubling of sliver; Air-jet = wrapped structure; Condensed = reduced spinning triangle on a ring frame.

Answer 1

The Correct Option is D

Analyzing each option: 
I Core sheath yarn - (ii) DREF yarn: DREF spinning (friction spinning) is often used to produce core-sheath yarns. A core yarn (for strength) is fed in, and then fibers are wrapped around it by the frictional forces. This is a correct match. 
II Back doubling - (i) Rotor yarn Back doubling is the process of doubling the slivers at the draw frame, to give an improvement in evenness. Rotor yarn is produced at the rotor spinning machine. Rotor spinning machine is fed by slivers. Therefore, it is right to say that rotor yarn is produced by back doubling. 
III Wrapped bundle of straight fibers - (iv) Two nozzle air jet yarn: Air-jet spinning (both single and two-nozzle) produces a yarn with a core of parallel fibers and a wrapper of surface fibers. This matches the description. 
IV Reduced spinning triangle - (iii) Condensed spun yarn: Condensed spinning is a modification of ring spinning where the spinning triangle (the zone where fibers are twisted into yarn) is reduced. This leads to better fiber integration and a stronger, more even yarn.