Write the following concept

Question 12 Marks

Groundwater table

Answer

The upper surface of the water accumulated below the ground is called the ground water table.
Factors like seasons, porosity of rocks, amount of rainfall, etc. affect the level of water table.
The water table is closer to the ground during rainy seasons while it is deeper in the summers.?

Question 22 Marks

Work of groundwater and landforms

Answer

The rainwater seeps below the earth’s surface through porous rocks or the cracks in the rocks.
This water accumulates at the non-porous layer of the rock. This accumulated water is called groundwater.
The soluble minerals in the water get dissolved and flow with the groundwater. This is the erosional work of the groundwater.
When the groundwater evaporates or the volume of soluble minerals is more than the solubility of the groundwater, the deposition of dissolved materials starts.
Landforms like sinkholes, limestone caves, stalactites and stalagmites are formed.
Thus, the groundwater carries out the erosion, transportation and depositional work.

Question 32 Marks

Depositional work of sea waves

Answer

The eroded materials accumulate at the sea bed.
Because of tides, they keep on moving towards the coast and away from the coast.
They become fine because of attrition and hitting towards each other. Deposition of such materials occurs at the places where the effect of waves is less.
The landforms like beaches, sand bar, lagoons are formed due to depositional work.

Question 42 Marks

Erosional work of sea waves

Answer

When the waves break at the coast, they bring with them water, transported stones, pebbles, sand particles, etc.
This leads to the erosion of the coast. Because of the chemical and hydraulic action of the sea wave too, the erosion occurs.
The landforms like wave cut platforms, sea caves, sea arches, sea cliffs, etc. are formed because of the erosional work of the waves.

Question 52 Marks

Erosional and depositional work of wind

Answer

Erosional work of wind: Wind carries smallsand particles, small pebbles, etc. along with I it. These particles cause erosion along rockscoming in the way due to friction.
This leads to formation of mushroom rocks, deflation hollows, yardangs, etc.
Depositional work of winds: Sand particles that blow with the winds are of different shapes and sizes.
Those particles which are very fine are carried to larger distances while the larger ones get transported to shorter distances only.
These sand particles get deposited in deserts ; and semi-arid climates. As a result, specific landforms are formed.
Sand dunes, barchans, seifs, ripple marks, loess plains, etc. are formed by deposition by wind.

Question 62 Marks

Transportation and deposition by glaciers

Answer

The glaciers carry sediments with them. These sediments are called moraines.
Depending on the location of the deposits, moraines can be divided into 4 types: ground moraines, lateral moraines, medial moraines and terminal moraines.
The depositional work of glacier produces landforms like drumlins, eskers, etc.

Question 72 Marks

Erosion work by glaciers

Answer

Though the velocity of glaciers is less, the mass of the ice is more and hence the glacier erodes its own banks and its bed on a large scale.
The erosional work of glaciers produces landforms like cirques, aretes, horns, U-shaped valleys, hanging valleys and roche moutonnees (or sheepbacks).

Question 82 Marks

Transportation and deposition by rivers

Answer

A river flows down the slope from a hilly region.
At the foothills, the change in the slope causes deposition of coarse sediments.
As these are deposited in a triangular shape, they form an alluvial fan. As the steepness of the slope decreases and the transport capacity of the river reduces, it starts flowing slowly.
It bends (meanders) often in its way in an effort to cross even small obstacles.
By the time the river reaches the sea, its riverbed becomes very wide and its speed becomes very slow.
The sediments of the river get deposited in its bed and on its banks. The factors that determine the deposition of sediments are thelength of the rivers, volume of water, amountof sediments, and the slope of the river and the earth’s surface.
Thus, landforms like flood levees, flood plains,deltas are formed because of deposition of sediments.

Question 92 Marks

Erosional work of rivers

Answer

The rivers originate at a much higher altitude from the sea level.
Here, the river flows at a great speed and therefore, its power to erode is great.
The riverbed and the river banks get eroded because of the speedy flow of the river, sand particles, pebbles. Also, various tributaries join the main river.
All these lead to the formation of gorges (canyons), V-shaped valleys and waterfalls.

Social Studies Write the following concept