Which of the following fibre is rough to touch?

Wool

The correct answer is option 2. Wool.

The perceived texture or "roughness" of fibers can vary based on individual preferences and the specific characteristics of each type of fiber. In general, wool is often described as having a slightly rougher texture compared to silk and cotton.

Here's a brief explanation of the characteristics of these fibers:

1. Wool:

Wool fibers come from the fleece of sheep and other animals like goats (cashmere, mohair) and rabbits (angora). The texture of wool can vary depending on factors such as the breed of the animal, the processing method, and the fineness of the fibers.

While some wool types can be soft and luxurious, others may have a coarser texture, leading to a perception of roughness. The coarser wool fibers are often used in applications like outerwear and carpets.

2. Silk:

Silk is a natural fiber produced by silk-producing insects, most notably the silkworm. Silk fibers are known for their smooth, soft, and luxurious feel. Silk is often considered one of the smoothest and most comfortable natural fibers.

3. Cotton:

Cotton fibers come from the cotton plant's seed hairs. Cotton is known for its softness and breathability. Cotton fabric is generally smooth and comfortable against the skin.

It's important to note that the perception of roughness can be subjective, and individual preferences may vary. Additionally, the processing and finishing of fibers into textiles, as well as the weave or knit of the fabric, can influence the overall feel and texture of the final product. Some people may find certain types of wool to be soft and comfortable, while others may perceive it as rougher, depending on the specific characteristics of the wool fibers.