Rajasthan Board Class 10 Science Chapter 15 Solution Structure of the Earth RBSE Class 10 Science Solution for Chapter 15
Objective type questions
1.) What is not the name of the earth-
a) Bhoomi
b) Gaiy
c) Bhanu
d) Tera
Ans-c) bhanu
2.) At present how much part of the earth surface is covered with water-
a) 70%
b) 30%
c) 50%
d) Uncertain
Ans-a) 70%
3.) The most abdunt element found in earth-
a) Silicon
b) Gold
c) Oxygen
d) Iron
Ans-d) iron
4) Where was the largest of harappan civilization was found-
a) Dwarka
b) Dhoulavera
c) Surut
d) Karnawati
Ans- b) dhoulavera
5.) What is reasons for the occurrence of tides-
a) Sun
b) Moon
c) Both
d) Sun and moon being in a straight line
Ans- d) sun and moon being in a straight line.
Very short type questions.
6.) What is the reasons for sun being in the state of Uttarayan-dakshinayan?
Ans-earth revolves around the sun in one year, earth dies not stand straight on its axis but it is 23.5 degree inclined. that is the reasons for sun being in the state of Uttarayan- dakshinayan.
7.) What is the unit of measuring an Earthquake ?
Ans- Richter scale.
8.) What is the reasons for tsunami?
Ans-mostly tsunami are caused by large earthquakes on the sea floor and waves of high energy rise in the sea.
9.) Which types of winds arise due to the decreasing air pressure in the center?
Ans- cyclones
Short type questions
10.) What will be the condition of a place after an earthquake of the magnitude of 7 on richer scale had hit?
Ans-earthquake is one of the effects of internal tectonic forces. Earth quake manes the shaking of earth surface. Any activity inside the earth cause shaking. The intensity of the earth quake sometimes less that the earthquake is not even felt. The earthquake above the 6 are considered as destructive and above this are disastrous. The destructive earth quake of greater magnitude come only on the destructive edges.
11.) What are oceanic currents?
Ans-oceanic currents can also called a river flowing in the sea. In this the water fows continuously in a certain direction. In some oceanic currents warm water folws while in some the clod water. The reason for the flow of the folw of the oceanic current is not due to the slope but because of the difference in the inter temperature density. These currents affets the operation of the ships and the life of sea organism.
12.) What are the advantages of weathering forces in agriculture?
Ans-the forces of weathering has to be very useful from the point of agriculture. Soil is very important for agriculture and it is formed by the forces of weathering. Their role in the construction of plains for agriculture is important. Many types of chemicals come out of the rocks due to weathering.
13.) Write down four causes which helps in weathering?
Ans-plant and animal life, atmosphere and water are the major causes of weathering. It breaks down and loosens the surface minerals of rock so they can be transported away by agents of erosion such as water. Chemical, agricultural are the causes which helps in weathering.
14.) How the moon was born?
Ans-4.40 million years ago moon was formed by the collusion of an object of the size of Mars with earth. Moon is earth’s only natural satellite. By its produces marine tides helps the earth bend properly on its axis slows down the rotation of the earth.
Essay type questions
15.) Explain the internal structure of the earth. Also draw a well labeled diagram?
Ans- earth was formed about 4.5 billions years ago. Earth’s age is about one third of the age of the universe. Initially the earth was very hot. Todays we know that the earth’s structure is in the form of layers like onions peels. The distance from the surface to the center of the earth is estimated to be around 3900km so far it is has not bees been possible to make a hole deeper than 15km into the earth. The earth is made up[ of the three layers the upper layer of the earth is a solid layer called crust. It can also be considered as the skin layer of the earth. Its thickness is not inform at all the places. Earth surface is divided into two parts the hydrosphere and lithosphere. Most of the part of lithosphere is formed is formed from soil. The part of the hydrosphere, the lithiosphere and the atmosphere where life exist is called as the biosphere. The earth is considered as 70% water and 30% land.
The second layer of the earth is called as mantle. This is the thickest layer. It is normally made up of hot molten rocks. The amount of iron and magnesium in these silicate rocks is more as compared to the earth crust. In these part the mantle keeps moving up and down. The earth’s central part is called core. Being the deepest part, it is the hootest part of the earth. The core of the earth is divided into two parts. The internal core is belived to be solid and is purely formed of iron. Prer core has molten iron and nickel prominently present in it. Core density is much higher than that of the crust. Earth’s chemical structure is similar to that of the meteorites. So the earth can also be called a large meteorite.
16.) What do you mean by the earths internal tectonic powers ? Describe any two?
Ans-several types of the forces work continuously to change the surface of the earth these powers are called the tectonic powers. Tectonic powers are of two types a) internal tectonic powers and b) external tectonic powers
Internal tectonic powers- these forces work by staying inside the earth and can not be seen form outside. Their origin is due to the spreading of the rocks by molten, below the surface of the earth and also due to the shifting of the magma. Following are the internal tectonic forces types-
1.) volcano- volcano is the strangest event of the internal tectonic forces. The earth shakes due to the activity happening inside the earth and by breaking the curst the smoke , ash , vapours and gases being to flow out. Volcano name is named after volcanic islands. Volcano is related to earths womb. Due to the pressure lave rises in the form of tube and erupts and spreads all over. Some volcanoes are continuously active while some become active after a gap. Volcano are found in every part of the world, but generally they are found along a chain of mountains. Hot water springs are also formed due to volcanoes.
2.) Earthquake- it is one of the effects of internal tectonic forces. Earthquake means the shaking of earth surface. Any activity inside the earth cause shaking. The point from where the vibrations initiate is called the epicenter. Waves spread in all direction from the centre. The effect of earth quake depends on its intensity. The intensity of earthquake at any place depends on the intensity of the shaking of the earth’s womb and its distance from the epicenter. The earthquake under the water of sea is called seaquake. Earthquakes with a magnitude of 4weak, upto 5.5 are strong. Earthquake above 6 are considered as destructive and above this are disastrous. The causes for the origin of the earthquakes is the disturbance in the equilibrium in the internal structure of the earth
17.) What erosion? Explain the importance of the two types of erosion powers on human life?
Ans- the forces are move from its place are called erosional forces. Two important types of erosion powers on human life are as follows_
Erosion forces- air water and snow are three such substance found on the earth which flow from one place to another in large quantities. There is force in their drift. The large structures which come in their way breaks and flow away. Air, water and ice also do erosional work. There work does not end but they transport these substances collected from the place of erosion to far distances.
