Which of the following is known as artificial wool? 

Acrylic 

The correct answer is option 1. Acrylic.

Acrylic is known as artificial wool because it is a synthetic fiber that closely mimics the properties of natural wool. It is often used as a substitute for wool in various applications due to its wool-like appearance and characteristics. Here are some key points about acrylic as artificial wool:

1. Appearance and Texture: Acrylic fibers can be manufactured to resemble the look and feel of natural wool. They can be soft, fluffy, and have a similar texture to traditional wool fibers.

2. Warmth:  Acrylic fibers provide warmth, similar to natural wool. They have good insulating properties, making them suitable for use in sweaters, blankets, and other cold-weather clothing items.

3. Lightweight:  Acrylic is generally lighter than wool, making it a popular choice for garments where weight is a consideration. It can provide warmth without adding significant bulk.

4. Hypoallergenic:  Acrylic is often considered hypoallergenic, making it a suitable alternative for individuals who may be allergic to wool or other natural fibers.

5. Affordability:  Acrylic is typically more affordable than natural wool, making it an economical choice for products that require a wool-like appearance without the cost associated with genuine wool.

6. Color Retention:  Acrylic fibers have good color retention, meaning they can hold dye well and maintain their color vibrancy over time.

While acrylic is used as artificial wool in various applications, it's essential to note that it is a synthetic material, whereas wool is a natural fiber derived from the fleece of animals like sheep. Acrylic is commonly used in the textile industry for a range of products, including sweaters, scarves, blankets, and other items where a wool-like appearance and functionality are desired.