Assam SCERT Class 7 Social Science Chapter 3 The Earth’s Surface and its changes Question Answer Solution
Assam Board Class 7 Social Science Chapter 3 The Earth’s Surface and its changes all Question’s easy Solution by expert teachers. Assam SCERT Class 7 Social Science (SST) Chapter 3 The Earth’s Surface and its changes Solution.
Board |
Assam SCERT |
Class |
7 |
Book |
Social Science (SST) |
Topic |
Question answer |
1.) Write answers to the Following (within 30 words)
(i) What do you mean by atmosphere?
Answer:
We live on earth. The blanket of air surrounding the surface of earth is called as “Atmosphere”.
We all depends on atmosphere. In atmosphere various mixture of gases are there.
(iii) Write about temporary wind.
Answer:
Due to change in temperature and pressure in atmosphere, there is change in wind. The wind that blows from higher pressure to lower pressure because of changes in temperature and pressure over time is called as “Temporary wind”.
(iv) What is sand dune?
Answer:
We see different structures in desert. When wind blows in desert, it transfer sand from 1 place to another. When velocity of wind decreases, the blown away sand gets deposited and forming a “Hill” like structure. These structures is called as “sand dune”.
(v) What is an Ox-bow lake?
Answer:
The zigzag river in plains is called as “Meandering”. Due to continuous erosion and deposition along the banks of meander, the ends of meander come close. After some time meander cut-off from river and form a cut-off river is called as “Ox-bow Lake”
2.) Tick (√) the correct answers
(i) Which of the following gases protects us from the harmful rays of the sun?
(a) Carbon dioxide
(b) Nitrogen
(c) Ozone
Answer:(c) Ozone
(ii) The deposit of glacier is called-
(a) Floodplain
(b) Mushroom rock
(c) Moraine
Answer:(c) Moraine
(iii) Which of the following is a Precipitation in the form of Water?
(a) Rain
(b) Cloud
(c) Ice
Answer:(a) Rain
(iv) The place where mushroom-shaped rocks are found is
(a) Desert
(b) River valleys
(c) Floodplains
Answer:(a) Desert
(v) The most important atmospheric layer for human
(a) Mesosphere
(b) Stratosphere
(c) Troposphere
Answer:(c) Troposphere
(vi) The place where Ox-bow lakes are found is –
(a) Polar region
(b) River valley
(c) Desert
Answer:(b) River valley
3.) Match the given items:
(a) Trade wind (a) Middle course of a river
(b) Glacier (b) Local wind
(c) Loo (c) Ozone layer
(d) Meandering course (d) River of ice
(e) Stratosphere (e) Regular wind
(f) Earthquake
Answer:
(a) Trade wind (e) Regular wind
(b) Glacier (d) River of ice
(c) Loo (b) Local wind
(d) Meandering course (a) Middle course of a river
(e) Stratosphere (c) Ozone layer
4.) Give reasons (within 50 words):
(i) Wet clothes do not dry up easily in damp weather.
Answer:
We know, our atmosphere is filled with water vapours is called as “Damp weather”. In damp weather, When air heat, it increases capacity of absorbing water vapours. But Wet clothes do not dry up easily in damp weather because air not heat quickly hence water vapours absorbing capacity not increases.
(iii) Some desert rocks are mushroom-shaped.
Answer:
In desert, wind can blow away fine dust particles for long distance but it cannot blow sand particles for long distance. Capability of blowing sand particles at certain height is high. Due to this we can see rocks with the shape of “mushrooms” in desert.
(iv) The two Polar Regions are colder than the equatorial region.
Answer:
The sun rays fall directly on equatorial region throughout year hence it always experiences extreme heat at the same time, in polar region sun rays fall slantingly hence the two Polar Regions are colder than the equatorial region.