Tag: components of earth

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Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Which of the following statement is false?

  1. the P-wave shadow zone is larger than the S-wave shadow zone.

  2. P waves travel more slowly in the outer core than in the lower mantle

  3. Liquids do not transmit S waves

  4. Seismic waves follow curved paths through the interior of the Earth
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All seismic waves do not cause earth quake. Certain magnitude is necessary to cause an earthquake.

Region on earth’s surface where earth quake can be barely detected after an occurrence of a seismic wave is called shadow region.

In the given options all are correct but the statement ‘P-wave shadow zone is larger than the S-wave shadow zone’ is false and vice versa is true.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The physical evidence that the core is composed mostly of iron is ________________.

  1. the known mass of Earth requires material of high density at the core.

  2. volcanoes erupt material from the core to the surface.

  3. scientists have sampled the core and determined its composition.

  4. all of these.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Outer core: It is located beneath mantle. The outer core is composed of the melted metals like nickel and iron.

Inner core: It is composed of an iron–nickel alloy and some light elements.

Thus core is mostly constituted by iron. This fact can be known by the measurement of densities of various layers of earth. At the core there is a higher density and this density could only be possible by higher amounts of iron present in the core.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

When sesimic waves pass across the boundary between two different materials, ___________ .

  1. the waves change in velocity

  2. the waves refract

  3. the waves reflect

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Seismic wave is a wave of energy caused due to sudden break or explosion of a rock in the earth’s interior.

When seismic wave passes from one material to the other material it either reflects, refracts or changes it velocity.

This phenomenon of seismic reflection or refraction enables geologists to study the interior of earth because reflection and refraction differs with the type of material.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

What drives plate tectonics?

  1. Thermal convection

  2. Solar energy

  3. thermal conduction

  4. Erosion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tectonic plates are those that are present beneath the earth surface and have been moving throughout the earth’s history.

What drives tectonic plates is not known clearly but one theory is that the convection drives heated up plates to move towards the surface and after they reach the ceiling they are deflected sideways. 

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

Where is the Earth's magnetic field generated?

  1. In the outer core

  2. In the inner core

  3. In the crust

  4. In the mantle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Earth’s magnetic field exerts from earth’s interior to the outer surface.

Inner core is mostly made of iron and temperature is about 5,700°C, at this temperature iron is as hot as surface of sun, but crushing pressure caused by gravity prevents it from becoming liquid and hence cannot produce magnetic field.

But the outer core has a 2,000 km thick layer of iron, nickel, and small quantities of other metals. As the pressure is lower in outer core when compared to the inner core metals exists in fluid state. 

Differences in temperature, pressure and composition within the outer core cause convection currents in the molten metal and earths spin result in whirling movements of the liquid metal resulting in generation of electric currents and there by producing magnetic field.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world 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
Reveal answer Fill a bubble to check yourself
A Correct answer
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

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

The earth is made up of several __________ .

  1. concentric layears

  2. compositional layers

  3. structural layers

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

What region of the Earth takes up the greatest volume?

  1. the inner core

  2. the crust

  3. the mantle

  4. the outer core
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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

Multiple choice components of earth geography inside our earth the earth's structure structure of the earth our world earth and structure

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.