Important Questions Test: Sorting Materials into Groups - UPSC MCQ

Those substances that have less density than water floats on water surface such as plastic ball and feather.

Lustre is the shine on a material’s surface, which can be seen when rubbed with sandpaper.

Diamond is the hardest known natural substance due to arrangement of molecule of it.

Sugar is soluble in water while mustard oil, sand and plastic is insoluble in water.

Chair, table and plough are made up of wood obtained from plants.

Oiled paper allows some light to pass through but not clearly, making it translucent.

A stone sinks in water because it is denser than water.

Petrol is lighter than water as it floats on water surface when mixed with water.

Metal is strong and can withstand heat, making it ideal for cooking vessels.

The object through which light passes easily are called as transparent object. Clean glass, glass and thin sheet of plastic are transparent while muddy water is translucent.

The substance through which light do not pass easily is called as opaque object. Brick, book etc are example of opaque objects.

Glass is commonly used to make a tumbler because it is solid, impermeable to liquids, and easy to clean, making it ideal for holding liquids.

The action of air, water on metal surface is called as corrosion. Due to corrosion metallic objects lose their lustre

The ability of a solute to get dissolved in a solvent is called as solubility.

Rusting occurs when iron is exposed to both air (which contains oxygen) and moisture. The presence of both oxygen and water allows for the formation of iron oxide, commonly known as rust, through a series of chemical reactions. The moisture provides the medium for oxygen to react with the iron surface, leading to the formation of rust.

The sorting of objects into groups with each group having its own characteristic properties is called classification of objects. All the objects having similar characteristics properties are placed in one group different groups. And the objects having different properties are placed in different groups.
1. The classification of objects into groups makes it easier to locate them and work with them.
2. If we know the properties of any one member of the group, we can get an idea of the properties of the other members of this group.

• Newspapers, books, copies, and diaries are primarily made from paper.
• Paper is produced by processing plant fibers, mainly from trees.
• This material is lightweight, flexible, and can be easily printed on.
• Unlike leather, wood, or plastic, paper is both biodegradable and recyclable.
• Thus, the correct answer is option 4: Paper.

Chalk powder does not dissolve in water and settles down.

Sandpaper feels rough to touch because of its coarse surface.

Grouping materials helps us understand and compare their properties more easily.