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.

Materials are grouped together on the basis of similarities and differences in their properties. In everyday life, we often group materials for our convenience.

The material through which an object can be seen but not clearly is called translucent material. Hence, muslin cloth is a translucent material. Mirror and aluminum foil are opaque and glass tumbler is transparent material.

We can group or identified any materials with the help of density. Generally, density possess some characteristics. As density is the amount of mass per unit of volume. If an object is heavy and compact, it has a high density. So, a simple example is if you have ever tried to mix water and oil. Oil is less dense than water, so it floats on top. A boat also floats for the same reason. And iron or stone are denser than water. Hence, they sink in water.

Stones are generally opaque while glasses are transparent.

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.

Here, all the statements are correct. Hence, option [D] will be your answer.

Glucose is completely soluble in water because its particles are so small and spread uniformly in water that we cannot see them. But chalk powder, tea leaves and sawdust are insoluble in water and settle down at the bottom of the container.

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.

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.

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

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 property of substances by which they can be beaten into thin sheets is called malleability. Bricks, pots and many other things is made by soil as a form of wet clay. Wet clay has the property of malleability and bricks are burned in a kiln which makes them durable.

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.

Those substances through which things can be seen are called “transparent” substances. Example glass, water and air. Transparent material is used for making the front glass (windscreen) of a car.

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.