7th Grade > Chemistry
FIBRE TO FABRIC MCQs
Total Questions : 116
| Page 11 of 12 pages
Answer: Option A. ->
:
Reason: 2 Marks
Naming: 1 Mark
We should not wear synthetic fibres while working near fire because the fabric made out of synthetic fibres melt and stick to the body of the person wearing it in case the clothes catch fire.
Three fabrics which are safe to be worn while working near fire are:
:
Reason: 2 Marks
Naming: 1 Mark
We should not wear synthetic fibres while working near fire because the fabric made out of synthetic fibres melt and stick to the body of the person wearing it in case the clothes catch fire.
Three fabrics which are safe to be worn while working near fire are:
- Cotton
- Linen
- Wool
Answer: Option A. ->
:
:
Definition: 1 Mark
Reason: 2 Marks
The process of removing the woollen fleece off a sheep is known as shearing.
Shearing does not hurt the sheep because this process is similar to shaving. Only the extra layer of hair that grows above the skin is removed and the skin as such is not hurt.
Answer: Option A. ->
:
:
Steps and Explanation: 3 Marks
Steps given below are followed to obtain wool from sheep or other wool-bearing animals:
Step 1: Shearing
The fleece (hair) of sheep is shaved off . In olden days this was done using a pair of metal blades. But nowadays machine is used to cut off the fleece. This is similar to the shaving of beard or hair. This process is called shearing. Shearing is done generally in summer so that sheep could get new hair by winter to get protection against cold.
Step 2: Scouring
Fleece, after shearing, is washed properly to remove dirt and grease. The washing of fleece after shearing is called scouring.
Step 3: Sorting
After scouring, fleece is sorted according to texture. This process is called sorting.
Step 4: Picking
After sorting, fluffy fibres called burr are picked out from hair. Burr is the fibre that gives wool.
Step 5: Dying
After sorting and picking out of burrs, these are dyed in desired colours.
Step 6: Spinning
The fibres are then straightened, combed and rolled into yarns.
Answer: Option A. ->
:
Definition: 1 Mark each
Explanation: 1 Mark
The rearing of silkworms for the production of raw silk or the breeding and raising of silkworms for the production of silk economically is known as sericulture.
Moriculture is defined as the science of mulberry cultivation for silk production because the silkworm feeds on mulberry leaves.
Yes, a silkworm is a larva and a larva is a caterpillar as well.
:
Definition: 1 Mark each
Explanation: 1 Mark
The rearing of silkworms for the production of raw silk or the breeding and raising of silkworms for the production of silk economically is known as sericulture.
Moriculture is defined as the science of mulberry cultivation for silk production because the silkworm feeds on mulberry leaves.
Yes, a silkworm is a larva and a larva is a caterpillar as well.
Answer: Option A. ->
:
:
Identification: 0.5 Mark each
Classification: 0.5 Mark each
Definition : 1 mark
Silk - It is a natural fibre obtained from cocoon of silkworm.
Jute - It is a natural fibre that is obtained from stem of jute plants.
Nylon - It is a synthetic fibre.
Polyester - It is a synthetic fibre.
Synthetic fibres are those fibres which are man-made and are obtained from various chemical processes.
Answer: Option A. ->
:
:
Each point: 1 Mark
The advantages of polythene are as follows:
1) Polythene is tough.
2) It is durable.
3) It is light in weight.
4) It is a poor conductor of heat and electricity.
5) It can be moulded in different shapes.
Answer: Option A. ->
Silk
:
A
Fibres which are obtained from plants and animals are known as natural fibres. Silk is obtained from silkworms which makes it a natural fibre.
However, polyester, rayon and nylon are man-made fibres and are hence, synthetic.
:
A
Fibres which are obtained from plants and animals are known as natural fibres. Silk is obtained from silkworms which makes it a natural fibre.
However, polyester, rayon and nylon are man-made fibres and are hence, synthetic.
Answer: Option C. ->
under hair
:
C
:
C
A sheep has two types of fibres that form its fleece, the coarse beard and the fine soft under hair which grows close to the skin. The soft under hair fibre is used to make wool.
Answer: Option A. ->
protein
:
A
:
A
Caterpillar secretes fibre made of protein which hardens on exposure to air and becomes silk fibre.
Answer: Option D. ->
fleece
:
D
Wool is an animal fibre obtained from animals like sheep, angora goat, yak, alpaca, etc. All these animals have a thick coat of hair on their body. This coat of hair is called fleece.
:
D
Wool is an animal fibre obtained from animals like sheep, angora goat, yak, alpaca, etc. All these animals have a thick coat of hair on their body. This coat of hair is called fleece.
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