Question

Woollen clothes keep us warm during winter. It is so because wool.....

• A. is a poor conductor of heat
• B. is a good conductor of heat
• C. Increases body temperature
• D. Increases the radiation

Hint:

Remember that materials that keep you warm are called insulators, and insulators are poor conductors of heat. The same principle applies to blankets, the fur of animals, and the insulation in house walls.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
The question asks for the scientific reason why woollen clothes provide warmth in winter. This relates to the principles of heat transfer.

Step 2: Analyzing the Properties of Wool


The primary function of winter clothing is not to generate heat, but to prevent the heat generated by our bodies from escaping into the cold environment.

Wool fibers have a crimped or curly structure, which traps a large amount of air between them.

Air is a very poor conductor of heat (an insulator).

By trapping a layer of air close to the body, wool prevents the convective and conductive loss of body heat. Therefore, wool itself is considered a poor conductor of heat, or a good insulator.


Step 3: Evaluating the Options


(A) is a poor conductor of heat: This is correct. Wool traps air, and air is a poor conductor, thus preventing body heat from escaping.

(B) is a good conductor of heat: This is the opposite of what is required for warmth. Good conductors, like metals, feel cold to the touch because they quickly draw heat away from your body.

(C) Increases body temperature: Woollen clothes do not generate or increase body temperature; they only help in retaining the heat the body already produces.

(D) Increases the radiation: This is incorrect. The function is to reduce heat loss, not increase radiation.


Step 4: Final Answer
Wool keeps us warm because it is a poor conductor of heat, effectively trapping body heat. Therefore, option (A) is the correct answer.