Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The yarn strength depends on the level of twist given in the final stage of ring spinning. Reason (R): Twist helps in binding the fibres through lateral pressure exerted by outer layers of fibres on the fibres in the core. In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Think of twist like a "hug" for the fibers. The tighter the twist, the harder the fibers are pressed together, making it harder for them to pull apart.

Answer 1

The Correct Option is A

Concept: A staple yarn (like cotton) consists of many short fibers. Without twist, these fibers would simply slide past each other when pulled, and the yarn would have zero strength.

Step 1: Analyzing Assertion (A).
In ring spinning, the amount of twist inserted is a primary factor in determining the yarn's final strength. As twist increases, the yarn strength typically increases up to an optimum point. Thus, (A) is correct.

Step 2: Analyzing Reason (R).
Twist acts by wrapping fibers helically around the yarn axis. This helical path causes the outer fibers to exert lateral (radial) pressure toward the yarn core. This pressure increases the friction between all the fibers, preventing them from slipping and thus providing structural integrity and strength. Thus, (R) is correct.

Step 3: Evaluating the Relationship.
Because the lateral pressure (R) is the physical mechanism that converts loose fibers into a strong yarn (A), the reason correctly explains the assertion.