Natural Resources - 2 - Free MCQ Practice Test with solutions, UPSC General

When the air is sucked out of the glass, the water will enter into the glass and thus, the level of water in the tub will go down.

Fossil fuels are the most important sources of energy for human beings. Coal and petroleum are kinds of sedimentary rock fossil fuels formed from the remains of plants and animals that lived million of years ago.

Air is a mixture of gases. About 78% is nitrogen, 21% is oxygen and the remaining 1% is mainly argon and carbon dioxide. Air also contains varying amounts of water vapour, dust particles and smoke.

The relationship in the box pairs a sedimentary rock (sandstone) and an igneous rock (pumice) together. Similarly, conglomerate is a sedimentary rock and obsidian is an igneous rock.

Clayey soil holds large amounts of water. On drying, this water escapes and cracks develop. These cracks break plant roots making clayey soil not suitable for plant growth.

Rate of dissolution of solute increases with increase in temperature and quantity of solvent. Beaker 4 has both, more amount of water and higher temperature which help in fast dissolution of salt in water.

When you will remove your hand, you will find that the card stays in place and the water does not flow out. This is because air exerts pressure on the card from below to keep the card in place. Here, the pressure exerted by air upwards is more than the pressure exerted by water downwards.

Water expands (increase in volume) upon freezing. This is due to the fact that upon freezing, water molecules crystallize  into an open hexagonal lattice form in which molecules enclose more space among themselves than in the liquid state. Thus, in the given case, volume of water increased when the water froze, forcing the stopper out of the bottle and forming the column of ice.

Due to the cooling effect of ice water, the air in the U-tube contracts, due to which the red ink X and Y move downwards.

At point Q, there occurs a gradual decrease in temperature of water, which could have been possible due to addition of ice cubes into the beaker of water.