8 class Interior of the earth geography question answers
Class 8 geography chapter 2 question answers pdf – Geography class 8 question answer pdf – Geography chapter 2 class 8 solution
Q 1. Tick the correct options in the box
(A)
There are two layers in the crust.
(i) Inner and outer crust
(ii) Continental and oceanic crust
(iii) Surface and oceanic crust
(iv) Mantle and Core
Ans:
(ii)Continental and oceanic crust
(B)
Which element is found in both mantle and crust ?
(i) Silica
(ii) Magnesium
(iii) Aluminium
(iv) Iron
Ans:
(i) Silica
(C)
Which of these minerals are found in the core of the earth?
(i) Iron-magnesium
(ii) Magnesium-nickel
(iii) Aluminium- Iron
(iv) Iron-nickel
Ans:
(iv) Iron-nickel
(D) The inner core is in which state?
(i) Gaseous
(ii) Solid state
(iii) Semi-solid state
Ans:
(ii) Solid state
(E) The outer core is made up of
(i) Iron
(ii) Gold
(iii) Hydrogen
(iv) Oxygen
Ans:
(i) Iron
(F) The layer of the earth on which welive.
(i) Mantle
(ii) Core
(iii) Crust
(iv) Continental crust
(G) Which seismic waves can travel through liquid medium?
(i) Primary waves
(ii) Secondary Waves
(iii) Surface waves
Geography chapter 2 class 8 question answer – Geography chapter 2 question answer Maharashtra board – Class 8 geography question answer solution
Q 2. Tell whether right or wrong. Correct the wrong statement
(A) The density of various materials is not the same in the interior of the earth.
Ans:
Right
(B) The core of the earth’s interior is made up of hard rock
Ans:
True
(C) Secondary waves cannot pass through outer core.
Ans:
Right
(D)
Continental crust is made up of silica and magnesium
Ans:
Wrong ( continental crust is made up of silica (si) and Aluminium (Al) .
Question answer of class 8 geography chapter 2 – Class 8 geography chapter 2 Interior of the earth question answers – Interior of the earth std 8 answers pdf
Q 3. Answer the following
(A) What are the two parts of the crust? What is the basis of classification?
Ans:
1)The crust is divided into two sub-layer continental crust and oceanic crust.
2)The continents are mainly composed of Silica (Silica is the compound of Silicon Elements) and Aluminum.
3)Oceanic crust is made up of silica and magnesium.
4)The
crust is classified on the basis of its thickness as well as the composition of
minerals.
(B) Why is the upper mantle called the asthenosphere?
Ans:
1)Mental is present below the crust of the earth.
2)The upper layer is more in liquid state and it is weaker zone that the molten rock materials i.e. magma find their way to the surface during volcanic eruptions.
3)Epicenters of deep seated eartquakes are also found here.
Therefore,
the upper mantle is called the asthenosphere.
(C) Magnetosphere of the earth is a result of rotation. Explain.
Ans:
1)The outer core of the earth’s interior is in a liquid state and the proportion of iron is more in this layer. The temperature of the liquid outer core is around 50000c.
2)Vertical currents originate in this liquid layer due to the difference between the temperatures of the outer and inner core.
3)The earth’s rotation gives them eddy (circular) motion. Hot liquid start flowing in upper direction and cooler liquid start flowing towards centre of the earth.
4)Electric current develop in these spiral eddies of liquid iron.
5)Thus magnetic field is generated. It is sometime called the geo-dynamo.
6)This magnetic field of the earth is functional even outside the earth’s surface for quite a distance. As a result, a cover develops around the earth because of the magnetic field.
7)The magnetic field thus developed around the earth, is called magnetosphere.
8)The earth’s atmosphere is protected from solar winds coming from the sun due to the magnetosphere.
9)Thus,
it can be said that magnetosphere of the earth is result of rotation.
Class 8 geography chapter 2 Interior of the earth question answers – Interior of the earth std 8 answers pdf – Interior of the earth question answers
Q 4. Draw neat diagrams, label them and explain.
(A) The interior of the earth
Ans:
1)The earth interior divided into the different layers.
2)The uppermost layer of the earth’s surface is in solid and is called the crust.
3)The crust is divided Into continental crust and oceanic crust.
4)The continents are mainly composed of Silica (Silica is the compound of Silicon Elements) and Aluminum and Oceanic crust is made up of silica and magnesium.
5)The crust is the thinnest of all the layers when compared to the mantle and core. The thickness of the earth is varies. Continental crust is thicker than the oceanic crust.
6)Mantle is lies below the crust of the earth. Mantle is divided into two layers upper and lower mantle.
7)The upper mantle is liquid state. It is extremely hot. In this layer find the magma.
8)The core start from around the depth of about 2900km from the earth’s surface. The part of the earth’s interior extending from the mantle upto the centre of the earth is the core.
9)This
layer is divided into outer core and inner core. The core of the earth’s is
responsible for the magnetic field, which protects form the high energy
particles of solar wind.
(B) Magnetic pole and equator
Ans:
1)The magnetosphere is the region of space surrounding earth where dominant magnetic field is the magnetic field of the earth, rather than the magnetic field of interplanetary space.
2)North-pole and south-pole are the two magnetic poles of the earth are different from geographical poles as shown in the above figure.
3)Equator
is an imaginary line along the middle of the earth at an equal distance from
the north-pole and south-pole.
Class 8 geography question answer solution – Question answer of class 8 geography chapter 2 – Class 8 geography chapter 2 Interior of the earth question answers
Q 5. Give geographical reasons:
(A) There is variety in the interior of the earth.
Ans:
There is variety in the interior of the earth due to the following reasons-
1)The continents crust are mainly composed of silica(Silica is the compound of Silicon Elements) and Aluminum. The density of continental crust is 2.65 to 2.90 gm/cm3.
2)The oceanic crust is made up of silica and magnesium. It was earlier called Sima. The density of this layer is 2.9 gm/cm3 to 3.3 gm/cm3.
3)Oceanic crust layer is approximately 7 to 10 km thick while the continental crust is approximately 30 km.
4)There is discontinuity between crust and mantle too. This discontinuity was deduced by a scientist called Mohorovicic.
5)There
is discontinuity between mantle and core too. The density of lower mantle is
about 5.7 gm/cm3. The density of outer core is 9.8 gm/cm3.
(B) There is correlation between the density of metals and their location in the interior of the earth.
Ans:
1)The inner core is in a solid state and consists of major elements like iron(Fe) and Nickel (Ni)
2)These metals are heavy. Hence, the density of the core is around 13.3 gm/cm3 which is more compared to the density of the mantle and the crust.
3)Moreover, metals like silica, aluminium and magnesium have lower density than nickel and iron. Hence, lighter metals are found close to the surface of the earth while heavier metals are found deep in the interior of the earth.
4)Thus,
there is a correlation between the density of metals and their location in the
interior of the earth.
(C) Mantle is the centre of earthquake and volcanic eruptions.
Ans:
1)Mental lies below the crust. Mantle can divide into two layers upper and lower mantle. The upper layer is more in liquid state, it aslo knon as asthenosphere.
2)In the upper layer magma chambers are found. It is through these chambers that magma comes out on the earth’s surface during volcanic eruptions.
3)The internal energy released due to endogenetic movements occurring in this layer is responsible for mountain-building, rifts, volcanic eruptions, earthquakes, etc.
4)Epicenters of deep seated earthquakes are usually found in this layer.
5)Therefore,
mantle is the centre of earthquake and volcanic eruptions.
(D) The thickness of the crust below the continents is less as compared to oceans.
Ans:
1)The thickness of the crust below the continents is from 16 to 45 km. 40 km under the mountain ranges and less than 10 km under the oceans.
2)The continents are mainly composed of silica(Silica is the compound of Silicon Elements) and Aluminum. The density of continental crust is 2.65 to 2.90 gm/cm3.
3)The oceanic crust is made up of silica and magnesium. It was earlier called Sima. The density of this layer is 2.9 gm/cm3 to 3.3 gm/cm3.
4)Oceanic crust layer is approximately 7 to 10 km thick while the continental crust is approximately 30 km.
5)Thus,
the thickness of the crust below the continents is less as compared to oceans.
(E) Earth is protected because of the Magnetosphere
Ans:
1)The magnetic field developed around the earth, is called magnetosphere.
2)The solar winds, containing charged particles, which come out of the higher part of the sun’s atmosphere are free from the gravitational force of the sun because of the extreme energy in them. Their velocity is more than the sound wave. It is approximately between 250km/sec to 750km/sec and can erode the earth’s atmoshphere.
3)However, the earth’s atmosphere is protected from the solar winds because of the magnetosphere.
**********
