Materials and Their Applications

So, it is water which is transparent in nature whereas iron, table and cloth are all examples of opaque materials.

Plastics are bad conductors of heat. So, they are used for the said purpose.

Glass is primarily made from sand (silica) and silicates (option C). The main ingredient in glass production is silicon dioxide (SiO2) found in sand, combined with various silicate compounds. Option A is incorrect because quartz is a form of silica itself, not combined with mica. Option B is incorrect because salt is not a standard glass ingredient.

Pyrex glass, also known as borosilicate glass, is highly heat-resistant due to its boron oxide content. This property makes it ideal for laboratory equipment and kitchenware. Other glass types like hard glass, flint glass, and bottle glass lack this specialized heat resistance.

The cement industry requires limestone (calcium carbonate) and clay (silica and alumina sources) as the two primary raw materials. These are heated in a kiln to form clinker, which is then ground with gypsum to produce cement. Individual materials alone (A or C) are insufficient, and gypsum (option B) is added later, not as a primary raw material.

Flint glass has a higher refractive index compared to crown glass, making it ideal for prisms and lenses where greater light bending is required. It contains lead oxide, which increases its refractive power and dispersion properties.

Yes,  it is correct.

Oiled paper is a translucent medium, i.e.  it allows the light to partially pass through it. This is the correct option.

Igloos are traditional shelters built by Inuit people using blocks of compressed snow and ice. The insulating properties of snow help trap air and maintain warmth inside, making ice the correct material choice.

Steel is the most elastic material among the options. Elasticity is defined as the ability to return to original shape after deformation. While rubber stretches more easily, steel has a higher elastic modulus and can undergo larger stress while still returning to its original shape. Wet clay deforms plastically (permanently), and plastic shows viscoelastic behavior with hysteresis.

This is an analogy question. Vitro is a prefix relating to glass (as in 'vitroceramic'). Similarly, Ligno is a prefix relating to wood (from 'lignin', the organic polymer in wood). Just as vitro-glass combinations involve glass, ligno-wood combinations involve wood.

This is the correct option because both gold and aluminium are lustrous metals.

This is the correct answer. All these objects are opaque as you cannot see through these objects.