Test: Water - UPSC MCQ

As solids are measured in kilograms, in the same way liquids are measured in litres. For example, 1 litre of water or 3 litres of milk.

The phenomenon of remaining on the surface of a liquid without sinking is called floatation.

As boat floats, in the same way a rock sinks.

Ducks, crocodiles and seals are all amphibious and can live on both land and water whereas fishes are odd one out who live only in aquatic environment.

Stagnant water is more prevalent in the rainy season as the water from the rains gets collected in the pits and potholes and does not get drained thus remaining at one place and becoming a breeding ground for insects.

Springs is the odd one out as it is a groundwater source of water whereas rivers, lakes and reservoirs are all surface-water sources of water.

Aquatic plants are also known as hydrophytes. 'Hydro' means water and 'phytes' means plants.

Mosquitoes and other insects breed profusely in stagnant water that is not flowing. Mosquitoes lay their larvae in them which grow to form the infected malaria causing mosquitoes.

A is the correct option.In earlier times, water was not as easily available as it is available today.

The water kept in an earthen pot remain cool even in summer because earthen pot has many small holes. Water seeps out through them and evaporates from the surface of the pot. The energy needed for evaporation is taken from the water kept in the earthen pot. As a result, water kept in earthen pot become cool.

To determine the correct answer, we need to understand the different sources of water extraction. Here are the details:
1. Groundwater sources:
- Groundwater refers to water that is stored underground in aquifers, which are layers of permeable rock or soil.
- It is extracted from wells that are drilled into the ground to reach the water table.
- Groundwater is a common and reliable source of water for domestic, agricultural, and industrial use.
2. Surface water sources:
- Surface water refers to water that is found on the Earth's surface, such as rivers, lakes, and reservoirs.
- It is extracted directly from these sources through various methods like pumping or diversion.
- Surface water is commonly used for public water supply, irrigation, and recreational activities.
3. Non-conventional sources:
- Non-conventional sources of water extraction include methods like rainwater harvesting, desalination, and wastewater treatment.
- Rainwater harvesting involves collecting rainwater and storing it for later use.
- Desalination is the process of removing salt and other impurities from seawater to make it suitable for drinking and irrigation.
- Wastewater treatment involves treating and purifying wastewater to remove contaminants before reuse.
4. None of these:
- This option indicates that none of the above options are correct for water extraction.
Based on the given choices and the details provided, the correct answer is:
A: Groundwater sources

The correct option is Option B. 
Surface water includes the lakes, reservoirs (human-made lakes), ponds, streams (of all sizes, from large rivers to small creeks), canals (human-made lakes and streams), and freshwater wetlands. The definition of freshwater is water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.

A waterwheel is a machine that converts the energy of free-flowing water into useful forms of power.

 Water is called a universal solvent.

Expansion and Contraction on Heating and Cooling
Introduction:
Expansion and contraction are physical phenomena that occur in various substances when they are heated or cooled. Let's examine which of the following substances show expansion on heating and contraction on cooling.
Explanation:
The substances that show expansion on heating and contraction on cooling are:
1. Liquids:
- Liquids expand on heating and contract on cooling.
- When a liquid is heated, its molecules gain energy and move faster, causing the liquid to expand.
- Conversely, when a liquid is cooled, its molecules lose energy and move slower, leading to contraction.
- Examples of liquids that exhibit this behavior include water, alcohol, and oil.
2. Gases:
- Gases also expand on heating and contract on cooling.
- When a gas is heated, its molecules gain energy and move faster, causing the gas to expand and occupy a larger volume.
- On the other hand, cooling a gas reduces the kinetic energy of its molecules, causing them to move slower and leading to contraction.
- Examples of gases that demonstrate this behavior include air, oxygen, and carbon dioxide.
3. Solids:
- Solids also undergo expansion on heating and contraction on cooling, but to a lesser extent compared to liquids and gases.
- When a solid is heated, its molecules vibrate more vigorously, causing the solid to expand slightly.
- Similarly, cooling a solid reduces the molecular vibration, resulting in contraction.
- Examples of solids that show this behavior include metals, such as iron and aluminum.
4. All of these:
- In summary, all three states of matter (liquids, gases, and solids) exhibit expansion on heating and contraction on cooling to varying degrees.
- Therefore, the correct answer is option D: All of these.
Conclusion:
Expansion on heating and contraction on cooling are observed in liquids, gases, and solids. These phenomena occur due to changes in molecular movement and energy levels. Understanding these properties is crucial in various scientific and engineering applications.

Petrol, wax and kerosene are not soluble in water. Juices are soluble in water.

Malaria is a mosquito-borne infectious disease affecting humans and other animals caused by Plasmodium species. Symptoms include headache, fever, shivering, joint pain (arthritis), vomiting, hemolytic anaemia, jaundice, haemoglobin in the urine, retinal damage, and convulsions. The disease is most commonly transmitted by an infected female Anopheles mosquito.

Animals that are capable of living on both land as well as water are called amphibians.

Earthenware pots keep the water cool so that thirsty travelers can have cold water.

Water spinach, Indian lotus, water caltrop are all aquatic plants which are used by humans as a food source.