Class 6 Science Chapter 2 MCQ

Some materials are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity, called metals. Examples of metals are iron, copper, aluminum, calcium, magnesium, etc. Electrical conductivity in decreasing order as Silver, Copper, Aluminum, Tungsten. Silver is the best conductor of heat and electricity because it contains a higher number of movable atoms (free electrons). Copper is used widely because of low cost than silver and gold.

In solids, particles are tightly packed. In liquids the space of particles is larger than solids but smaller than gases. The space between particles is maximum in gases. Generally, they are loosely packed.

Water is known as Universal solvent. As it dissolves maximum materials. Ink, milk, honey mixes very well in water whereas oil do not mix with water. Hence, option [D] does not belong to the group.

Stones are generally opaque while glasses are transparent.

Liquids that mix very well with one another called “miscible” and liquids that do not mix with one another called “immiscible”.

Through magnifying glass and glass tumbler we can see the objects clearly so these materials are transparent.

Water is known as Universal solvent. As it dissolves maximum materials. But oil, chalk, sawdust and sand are not dissolved in water.

Shopkeepers usually prefer to keep biscuits, sweets and other eatables in transparent containers of glass or plastic, so that buyers can easily see these items. And container saves the product from attack of fugus, dust and foreign materials.

Wood, glass and leather materials cannot be used for making safety pin. Steel and plastic are commonly used for making a safety pin.

The appearance of the material deals with the look, texture and feel. In addition to lustre, colour, shape, quality and states (solid, liquid, gaseous, plasma) defines the property of appearance of the material. Hence, option [D] will be your answer.

In solids, particles are tightly packed. In liquids the space of particles is larger than solids but smaller than gases. The space between particles is maximum in gases. Generally, they are loosely packed. Hence, intermolecular force attraction found strongest in solids, weaker in liquids and weakest in gases.

Substances through which things can be seen are called “transparent” substances. Example glass, water and air. Substances through which things can be seen but not clearly are called “translucent” substances. Example oiled paper, muslin cloth.

Materials through which things cannot be seen are called “opaque” substances. Example wood, metals etc. Our palm and most of body parts are opaque. But when it (flesh, skin, cartilages, nerves) kept in powerful light source, it behaves like “translucent”. But still, the X-ray light source is not able to cross the bone of our body.

Gold, silver and diamond have shiny appearance are said to have luster. Wood has dull appearance, so wood is not lustrous.

In everyday life, we often group materials for our convenience. But we usually store things in a manner that similar materials make a separate group and such an arrangement helps us to locate them easily. Hence, at home, we usually store things in such a manner that objects are easily separated in a group.

An iron nail kept in soft drink would lost its shine and appear dull become soft drink contains carbonic acid which reacts with iron nail, so it gives dull appearance. Iron nail has no reaction with mustard oil, coconut oil and kerosene, so does not lose its shine, when kept in these solutions.

Aluminum, iron and copper are the metals while Sulphur is non-metal.

Among of these, here graphite (non-metal) is a good conductor of heat.

Tawa, spade and pressure cooker are all hard materials i.e. cannot be easily compressed, cut, bent (molded) or scratched but eraser can be easily cut, bent or scratched. So, the odd one is eraser.

The materials which allow heat to pass through them easily are “conductors” of heat. For examples, aluminum, iron and copper. The materials which do not allow heat to pass through them easily are poor conductors of heat such as plastic and wood. Poor conductors are known as “insulators”.

We know that some materials are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity, called metal. Iron is very hard and strong metal and it is found everywhere and relatively cheaper than any other metals. Therefore, we use an iron metal or rod in window as well as door lock.

Density of oil is less than that of water that’s why oil floats in the water. Density of oil is about 90% of water density. So the specific gravity of oil is almost 0.9. Density of water = 1 kg / litre. So, density of oil = 0.9 kg /litre It means, 0.9 kg oil = 1 litre oil. 1 kg oil = (1/0.9) litre = 1.1 litre. Hence, 1 kg of oil occupies more space compared to 1 kg of water.

Water is a conductor of electricity. Pure water is actually a good insulator. Tap water can be a good conductor due to calcium, magnesium, and carbonate ions, or other substances. Any impurities, like salts, in the water enable it to conduct electricity. Pure water does not conduct electricity. This is because pure water do not contain any salts or components.

A hydrometer is an instrument used to measure the specific gravity or relative density of liquids, i.e. the ratio of the density of the liquid to the density of water. A barometer is a scientific instrument that is used to measure air pressure or atmospheric pressure in a certain environment. A hygrometer is an instrument used to measure the amount of humidity and water vapour in the atmosphere, in soil, or in confined spaces. An ammeter (from Ampere Meter) is a measuring instrument used to measure the current in a circuit.

Materials are grouped for our convenience and to make it convenient to study their properties. Materials are also grouped according to their uses. So, only statement [C] is not true.