Tag: earth and structure

Questions Related to earth and structure

The boundary between the mantle and the core lies at a depth of approximately ________ .

  1. 3000 kilometers

  2. 300 kilometers

  3. 1000 kilometres

  4. 5000 kilometers


Correct Option: A
Explanation:

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

The boundary between the mantle and the core lies at a depth of approximately 2891 km or 3000km.

The core–mantle boundary of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core

The earth is made up of several __________ .

  1. concentric layears

  2. compositional layers

  3. structural layers

  4. none of these


Correct Option: A
Explanation:

The earth is made up of three layers, one inside the other like an onion. They are the crust, the mental and the core. The topmost layer, that is, the crust is solid, the thinnest and the lighter. The average density is 2.75 to 2.90. The thickness is 8 to 100 km. Below this top layer is the layer of basalt rock which is heavier than the topmost layer, i.e, the mental. The average thickness is 100 2900 km and the density varies from 3.1 to 5.00. The innermost layer is the core. The core contains 1/3 of the entire mass of the world. The average density is 5.1 to 13.00.

What region of the Earth takes up the greatest volume?

  1. the inner core

  2. the crust

  3. the mantle

  4. the outer core


Correct Option: C
Explanation:

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

Widest of all the layers of earth is Mantle which is 1800 thick. It is composed mostly of silicate rocks rich in magnesium and iron.

Which one of the following lists most accurately describes oceanic crust?

  1. granitic - density of 3.0 $g/cm^3$

  2. basaltic - density of 3.0 $g/cm^3$

  3. basaltic - density of 2.6 $g/cm^3$

  4. quartz arenites - density of 2.6 g/cm3


Correct Option: B
Explanation:

Basalt is dark coloured igneous rock mainly composed of pyroxene mineral. It most commonly forms as an extrusive rock, such as a lava.The oceanic crust consists of a volcanic lava rock called basalt. Oceanic crust is the thin crust underlying the oceans.

Basalt density present is equal to 3.0 g /cm'3

Fold mountains are the result of large-scale earth movements caused by:

  1. heat in earth's crust

  2. stresses in the earth's crust

  3. movement in the earth's crust

  4. none of these


Correct Option: B
Explanation:

The crust of the earth is made up of different strata of rocks. As a result of movement inside the earth, these rock strata at times are forced up and down and thus fold mountain are created. So fold mountain are the result of large-scale earth movement caused by stresses in the earth's crust.

The oceanic crust consists mainly of _________.

  1. basaltic rocks

  2. granitic rocks

  3. gabbroic rocks

  4. ultramafic rocks


Correct Option: A
Explanation:

The oceanic crust consists of a volcanic lava rock called basalt. Oceanic crust is the thin crust underlying the oceans. Basalt is dark coloured igneous rock mainly composed of pyroxene mineral. It most commonly forms as an extrusive rock, such as a lava.

Basalt density present is equal to 3.0 g cm'3

The lithosphere includes:

  1. asthenosphere and mesosphere

  2. crust and uppermost, rigid mantle

  3. outer core and lower mantle

  4. outer core and inner core


Correct Option: B
Explanation:

Earth mainly consists of four layers namely crust, mantle, outer core and inner core.

Lithosphere is the rigid outer layer of the earth which includes crust and uppermost mantle.

Crust: This is about 8 km thick inside and is highly explored. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic lava rock called basalt.

Mantle: It is composed mostly of silicate rocks rich in magnesium and iron.

SIAL and SIMA are the divisions of __________.

  1. lithosphere

  2. hydrosphere

  3. biosphere

  4. none of these


Correct Option: A
Explanation:

The topmost layer of the earth is solid, the thinnest and the lightest and is known as lithosphere. The lithosphere has two layer- the outer part and the inner part. The outer part which is immediately below the newer sedimentary formation, i.e, crust. The outer layer of lithosphere mainly found under the continent and inner layer it mostly found partly under oceans. The inner layer again has three layers, i.e, SIAL which is made of silica and aluminum. The average thickness is 8 to 100 km. The layer next to it is SIMA makeup of silica and magnesium and an average thickness of this layer is 100 to 2900 km. The innermost layer is NIFE madeup of nickel and ferrous and the density is 5.1 to 13.

The hard and resistant materials forming the earth's crust are called _____________.

  1. Rocks

  2. Metals

  3. Minerals

  4. Lava


Correct Option: A
Explanation:
  • The hard resistant materials forming the earth's crust are called the rocks. Hence option A is correct
  • In different types of rocks, different metals and minerals are found.
  • Lava is the molten material that gets ejected out of a volcano.

The crust of the Earth, by and large, is ___________.

  1. rocky

  2. plain

  3. wrinkled

  4. None of these


Correct Option: C
Explanation:
  • The earth's crust is the outermost layer of the earth which has cooled down while the inner layers are still burning. When things cool after burning they get wrinkled up hence the earth's crust is largely wrinkled.
  • It is plain, plateau and mountainous at different places and rocky as well. The most appropriate answer is option C ie wrinkled.