Lesson7 Geography
(EXTERNAL FORCES-RESPONSIBLE FOR CHANGES)
A.Choose the correct option of the following
Question 1.By which
process the materials of broken rocks assemble at its original place
(a) Weathering
(b) Transportation
(c) Erosion
(d) Deposition
Answer:
(a) Weathering
Question 2.Where among
the following winds perform its work?
(a) In deserts
(b) In Mountains
(c) In coastal areas
(d) In plains
Answer:
(a) In deserts
Question 3.Which is
vital factor that makes soil fer-tile?
(a) The original rock materials
(b) Humus
(c) Climate
(d) Man
Answer:
(b) Humus
B.Fill in the blanks:
1.When the rock breaks into pieces without chemical reaction is Biological
weathering
2.The process of flattening of unleavened surface is called Surface Balancing
3.With the deposition Oxbow
lake is formed.
4.On the Orissa
coast in India Chilka Lake is an
example of lagoon-lake.
Question 1.Which are the three works of river?
Answer:Erosion, Transportation & Deposition are three works of river.
Question 2.Which
are three stages of river?
Answer:There are three stages of river, young, matured and old age.
Question 3.What
is estuary?
Answer:Some of the rivers become wider at their meeting point with sea and sweep
away into deep sea.
Question 4.What
is geyser?
Answer:The underground hot water is thrown up in the form of fountain is called
geyser.
Question 5.How is the Yardage formed?
Answer:Yardage is formed by wind erosion.
Question 6.What
is Lagoon?
Answer:The sea water enclosed between the coast and sand bar is known as
lagoon.
D.Short Answer Type Questions
Question 1.Write the factors
that help soil formation?
Answer:The weathering and erosion process of rocks from the soil. The helping
agents in soil formation are parent rocks, surface shape, climate &
vegetation.
Question 2.What is
weathering? Write the names of different types of weathering?
Answer:Weathering is the iocal process in which graduation and split of rocks
occur at their original place. The types are physical, chemical and biological
weathering.
Question 3.Differentiate
between slow and rapid wasting?
Answer:The process of surface sliding by weathering is slow wasting and the
process of filling up the holes is high wasting.
Question 4.How the V – shaped
valley is formed?
Answer:The V – shaped valley is formed when river reaches its base level and
widens its banks. V – Shaped Valley
Question 1.Discuss the surface Balancing?
Answer:The widening and flattening of the surface is called surface Balancing.
Rivers, glaciers, wind, underground water and sea waves are the key agents of
leveling. The Surface Balancing can be classified in to two categories.
1. Slow wasting
2. Rapid wasting.
1. Slow wasting:
The rapid erosion cycle shifts the rocks from its original place by rubbing,
cut-ting & peeling to decrease the high elevated areas.
2. Rapid wasting:
The process of deposition of weathered materials in low-lying regions or holes
is called aggravation and the weathered materials fill up the holes whose
height kept on growing is called Rapid wasting.
Question 2.What is soil erosion? Write its cause and ways to
conserve soil?
Answer:The natural forces or human activities which help in removing the layer
of soil is called soil erosion. The causes of soil erosion are as follows:
- When the cover of vegetation is
removed the upper layer of soil gets loose.
- Heavy rains and powerful wind
remove the Soil content and layer.
- Overgrazing by domestic
animals.
- Cutting trees and clearing
forest cover.
- Excess use of fertilize &
pesticide.
The measures to
conserve soil are:
- To protect forest. Trees
tighten the soil material.
- Tree plantation in river
valleys, barren land and mountain slopes.
- Soil rehab of the land which
becomes uneven due to water can be leveled to stop erosion.
- Controlled grazing.
- Flood control measures by
building stop dams.
- Crop rotation by planting crops
alter – neatly.
