Question

At places, the groundwater is stored between layers of hard rock below the water table .this is known as __________.
A.a reservoir
B.an aquifer
C.a hard water
D.a well water

Answer 1

Hint:The question specifies that the water body is stored between two layers of hard rock now. Depending on the porosity of rocks groundwater can be confined or unconfined. Out of the options given, identify which option relates to the water body stored beneath the surface of the earth.

Complete answer:
-To get the solution of the above mentioned question we have to first understand what is groundwater and what factors are responsible for the existence of groundwater.
-Groundwater is the water present beneath Earth’s surface in soil pore spaces and in the fracture of rock formations.
-There are some factors which are responsible for existence of groundwater such as
 -Gravity, it pulls water and everything else towards the center of earth.underground water that has come mainly from the seepage of surface water and is held in previous rocks.
-The bottommost layer in the earth’s surface is called the bedrock. These rocks have not undergone any weathering as they are protected by the layer of rocks that are above them. The weathered away product of these rocks is what we see in the topsoil and the subsoil

-The underground layer of rocks which contains and transmits groundwater in a limited range is the place called an aquifer.
-Aquifers may or may not be closer to the surface of the earth. If they are, they are more likely to be used for water supply and irrigation purposes. They can be replenished during the monsoon season.
Hence the correct option is B an aquifer.

Note:
-Groundwater is a limited resource. Even though it can get replenished by the rains, the rate at which groundwater is being used is more than the rate at which water is being filled back again.
-Ground water is fit for direct drinking since, as it passes through multiple rocks, all the impurities get filtered out. Essential minerals from these rocks are dissolved into the water.
-Aquifers can be confined or unconfined depending on the type of their geomorphology.
-Confined aquifers are found deep below the surface, which means they are very high pressure and are overlain by impermeable rock .
-Unconfined aquifers are those which are closer to the surface and it is in contact with above surfaces, hence it is at atmospheric pressure.