Materials and Their Applications

Rollers are typically made of wood, stone, or iron. Steel is generally not used for agricultural rollers due to cost and weight considerations compared to other materials.

Elasticity is defined by the ability of a material to return to its original shape after the deforming force is removed. Steel is more elastic than rubber because it requires a much greater force to produce the same amount of strain.

Graphite is a pure form of carbon, which is a chemical element. Silica, magnesia, and glass are compounds or mixtures.

Elasticity is the ability of a material to return to its original shape after a deforming force is removed. Among the choices, rubber is well known for its high elastic limit and ability to undergo significant reversible deformation.

Crown glass is commonly used for spectacle lenses because it has good optical clarity and is relatively durable.

Glass is primarily manufactured by melting a mixture of silica (sand), soda ash, and limestone. Among the choices, sand and silicate represent the primary components.

It contains up to 1.5% carbon. Increases the carbon content makes the iron harder, but more brittle thus it is used for cutting tools and masonry nails. Masonry nails are designed to be hammered into concrete blocks and if a worker miss hit a masonry nail, it tends to break into two bits because of its increased brittleness.

Rubber, wool, cotton, paper etc. cannot be used for making utensils as they do not have much of strength. Glass and plastic are the materials used for such purposes. 

Lustrous means shiny. Iron, copper and silver are metals and all metals have shiny surface. Diamond, glass and steel are also shiny. Wood and coal are the substances which appear dull and non lustrous. 

Out of wood, iron, stone and glass, only iron is a metal (element), whereas the rest are not. 

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This is correct. Glass is used to make windows of a pucca house.

This is the correct choice. Cement and wood will keep the roof and walls of a house safe when it rains. Wooden walls and sloping wooden roofs are made in hilly areas where it rains a lot. Cement is also a good choice.

This is correct a kutcha house is made of mud, bamboo, grass, thorny bushes, grass, plastic sheets, etc.

Carbon paper, wood and cardboard are opaque objects which cannot form images, whereas silvered glass refers to an object which is painted on one side, the other surface of which can act as a reflecting surface, thus acting as a mirror.