TEST 01: GEOGRAPHY

Syllabus: Introduction, Solar system and Interiors of the earth. 

Q1. Which of the following are correctly matched?

a) The moon- The big Splat theory

b) Origin of universe- The Big Bang theory

c) Evolution of earth- The Nebula Hypothesis

d) All are correctly matched

Q2. Make correct pairs from the following two columns and mark the correct option.

1. Meteorology    A. Population Geography

2. Demography   B. Soil Geography

3. Sociology        C. Climatology

4. Pedology         D. Social Geography

(a) 1B, 2C, 3A, 4D          (c) 1D, 2B, 3C, 4A

(b) 1A, 2D, 3B, 4C          (d) 1C, 2A, 3D, 4B

Q3. Arrange the following in the order of shortest to longest duration on Geological Time Scale?

(a)Epoch-Period-Era-Eons

(b)Eons-Era-Period-Epoch

(c)Epoch-Eons-Period-Era

(d)Era-Period-Epoch-Eons

Q4. Consider the following statements regarding Nebular theory of Laplace?

1. The sun was surrounded by solar nebula containing mostly the hydrogen and silicon.

2. The collision of particle led to formation of a disk-shaped cloud and planets were formed through the process of accretion.

Choose the correct statements?

a) Only 1

b) Only 2

c) Both 1 and 2

d) None of the above

Q5. Choose the correct statements regarding inner planets?

a) Planets between the sun and the earth.

b) Planets between the sun and the belt of asteroids.

c) Planets in gaseous state.

d) Planets without satellite

Q6. Consider the following statements regarding the characteristics of Terrestrial Planets?

1. The terrestrial planets were formed in the close vicinity of the parent star where it was too warm for gases to condense to solid particles.

2. The terrestrial planets are larger than Jovian planets and their lower gravity could hold the escaping gases.

Choose the correct statement?

a) Only 1

b) Only 2

c) Both1 and 2

d) None of the above

Q7. Which of the following statements are incorrect regarding formation of stars?

a) A galaxy (large number of stars) starts to form by accumulation of helium gas.

b) The formation of stars is believed to have taken place some 5-6 million years ago.

c) The initial density difference in early universe is the core reason for star formation.

d) Both (a) and (b)

Q8. What are ‘planetesimals’ associated with theories of planet formations?

a) They are formed by cohesion of small rounded bodies of condensed gas cloud with the matter around the core.

b) They are a combined object formed around the comets and meteorites.

c) Large number of dwarf planets form one planetesimal.

d) None of the above

Q9. Which one of the following processes is related to the formation or modification of the present atmosphere?

a) Solar winds

b) Degassing

c) Photosynthesis

d) All of the above

Q10. Which of the following statements regarding our solar system are incorrect?

a) The distance between celestial bodies are measured by light years.

b) All the planets were formed in the same period sometime.

c) Our Solar system consists of nine planets.

d) All the statements are correct

Q11. Seismology helps us understand the origin and intensity of earth’s interior. Consider the following statements regarding Seismic waves?

1. All seismic waves are mechanical waves and require medium to propagate.

2. Their behavior change with the change in medium

Choose the correct option?

a) Only 1

b) Only 2

c) Both 1 and 2

d) None of the above

Q12. Which of the following seismic waves is correctly matched with its respective property?

1. Secondary Waves surface seismic waves that cause horizontal shifting of the Earth during an earthquake.

2. Love Waves can pass through all the mediums.

3. Rayleigh Waves a type of surface acoustic wave that travel on solids

Choose the correct answer?

a) Only 1

b) Only 2

c)  Only 3

d) All are correctly matched.

Q13. Consider the following statements regarding layered structure of earth:

1. Inner Core is the densest layer of earth’s interior.

2. Continental crust is less dense than the oceanic crust.

Choose the correct statements?

a) Only 1

b) Only 2

c) Both 1 and 2

d) None of the above

Q14. Consider the following statements regarding the gravitation force of the earth:

1. Gravitation force is not same at different latitudes on the surface.

2. Gravitational force is greater near the poles and less at the equator.

Choose the incorrect statements?

a) Only 1

b) Only 2

c) Both 1 and 2

d) None of the above

Q15. which of the following statements is correct regarding the composition of interior of the Earth?

a) Earth as a whole is composed of mainly iron (Fe) but the earth’s crust consists of mostly oxygen.

b) The temperature and pressure increase with the increasing distance from the surface towards the interior in deeper depths.

c) Continental crust is thicker than oceanic crust.

d) All of the above.

Q16. Consider the various sources of information about the interior of the earth:

1. Seismic Activity

2. Volcanoes

3. Gravitational force

4. Earth magnetism

5. Meteors

6. Surface Rocks or Mined Rocks

Which one of the above sources are indirect source of information about the Interior of the Earth?

a) 1,3,4 and 5

b) 1, 2,3 and 5

c)  6 only

d) All of the above

Q17. Which of the following statement is the most appropriate reason of earthquake waves developing a shadow zone?

a) Composition of material in the shadow zone is impermeable.

b) The body waves (p and s waves) follow the Snell’s law when they pass from one medium to another and hence deflect from the path.

c) Secondary waves do not pass through liquid medium (outer core).

d) Both (b) and (c).

Q18. Which of the following are correctly matched?

1. Lithosphere – the crust and the uppermost part of the mantle.

2. Shadow zone – the upper portion of the mantle.

3. Asthenosphere – NIFE layer

Choose the correct answer:

a) Only 1

b) Only 2

c) Both 1 and 3

d) All are correctly matched.

Q19. Seismic activity is one of the most important sources of information about the interior of the earth. Choose the correct statement(s) regarding the nature of p and s waves:

a) Both P and S can only travel in solid and gas mediums.

b) P waves speed is highest in solid medium.

c) S wave shadow zone form the boundary of outer core as it is in liquid state.

d) Both (b) and (c)

Q20. Magnetic materials in the crustal portion provide information about the distribution of materials in the interior of earth. Which of the following statements is true regarding the earth’s magnetic field?

a) Earth has a dipole magnetic field that deflects solar wind.

b) Flow in the liquid iron outer core creates a magnetic field.

c) Solar wind contains electromagnetic particles that are deflected by earth’s field. These particles distort the shape of earth’s magnetic field in space.

d) All of the above.

Answers:

1. D

• A large number of hypotheses were put forth by different philosophers and scientists regarding the origin of the earth. One of the earlier and popular arguments was by German philosopher Immanuel Kant. Mathematician Laplace revised it in 1796. It is known as Nebular Hypothesis. However, scientists in later period took up the
• problems of origin of universe rather than that of just the earth or the planets. The most popular argument regarding the origin of the universe is the Big Bang Theory. It is also called expanding universe hypothesis.
• It is generally believed that the formation of moon, as a satellite of the earth, is an outcome of ‘giant impact’ or what is described as “the big splat”.

2. D

3.A

4. B

• Nebular Hypothesis considered that the planets were formed out of a cloud of material associated with a youthful sun, which was slowly rotating. Later in 1950, Otto Schmidt in Russia and Carl Weizascar in Germany somewhat revised the ‘nebular hypothesis’, though differing in details.
• They considered that the sun was surrounded by solar nebula containing mostly the hydrogen and helium along with what may be termed as dust.
• The friction and collision of particles led to formation of a disk-shaped cloud and the planets were formed through the process of accretion.

5. B

• Our solar system consists of the sun (the star), 8 planets, 63 moons, millions of smaller bodies like asteroids and comets and huge quantity of dust-grains and gases. Out of the eight planets, Mercury, Venus, Earth and Mars are called as the inner planets as they lie between the sun and the belt of asteroids the other four planets are called the outer planets.
• Alternatively, the first four are called Terrestrial, meaning earth-like as they are made up of rock and metals, and have relatively high densities. The rest four are called Jovian or Gas Giant planets. Jovian means Jupiter-like.

6. A

• The first four planets are called Terrestrial, meaning earth-like as they are made up of rock and metals, and have relatively high densities. The rest four are called Jovian or Gas Giant planets. Jovian means Jupiter-like. Most of them are much larger than the terrestrial planets and have thick atmosphere, mostly of helium and hydrogen.
• (i) The terrestrial planets were formed in the close vicinity of the parent star where it was too warm for gases to condense to solid particles. Jovian planets were formed at quite a distant location.
• (ii) The solar wind was most intense nearer the sun; so, it blew off lots of gas and dust from the terrestrial planets. The solar winds were not all that intense to cause similar removal of gases from the Jovian planets.
• (iii) The terrestrial planets are smaller and their lower gravity could not hold the escaping gases.

7. D

• The distribution of matter and energy was not even in the early universe. These initial density differences gave rise to differences in gravitational forces and it caused the matter to get drawn together. These formed the bases for development of galaxies. A galaxy contains a large number of stars.
• Galaxies spread over vast distances that are measured in thousands of light-years. A galaxy starts to form by accumulation of hydrogen gas in the form of a very large cloud called nebula.
• Eventually, growing nebula develops localized clumps of gas. These clumps continue to grow into even denser gaseous bodies, giving rise to formation of stars. The formation of stars is believed to have taken place some 5-6 billion years ago.

8. A

• Development of planets:
• (i) The stars are localized lumps of gas within a nebula. The gravitational force within the lumps leads to the formation of a core to the gas cloud and a huge rotating disc of gas and dust develops around the gas core.
• (ii) In the next stage, the gas cloud starts getting condensed and the matter around the core develops into small rounded objects. These small-rounded objects by the process of cohesion develop into what is called planetesimals. Larger bodies start forming by collision, and gravitational attraction causes the material to stick together. Planetesimals are a large number of smaller bodies.
• (iii) In the final stage, these large number of small planetesimals accrete to form a fewer large bodies in the form of planets.

9. D

• The present composition of earth’s atmosphere is chiefly contributed by nitrogen and oxygen. The first stage is marked by the loss of primordial atmosphere. In the second stage, the hot interior of the earth contributed to the evolution of the atmosphere. Finally, the composition of the atmosphere was modified by the living world through the process of photosynthesis.
• The early atmosphere, with hydrogen and helium, is supposed to have been stripped off as a result of the solar winds. During the cooling of the earth, gases and water vapour were released from the interior solid earth. The process through which the gases were outpoured from the interior is called degassing. Continuous volcanic eruptions contributed water vapour and gases to the atmosphere.

10.C

• Our Solar system consists of eight planets. The nebula from which our Solar system is supposed to have been formed started its collapse and core formation some time 5-5.6 billion years ago and the planets were formed about 4.6 billion years ago.
• Our solar system consists of the sun (the star), 8 planets, 63 moons, millions of smaller bodies like asteroids and comets and huge quantity of dust-grains and gases. All the planets were formed in the same period sometime about 4.6 billion years ago.
• Till recently (August 2006), Pluto was also considered a planet. However, in a meeting of the International Astronomical Union, a decision was taken that Pluto like other celestial objects discovered in recent past may be called ‘dwarf planet’.

11.C

• Seismic waves are waves of energy that travel through the Earth’s layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy.
• Seismic wave fields are recorded by a seismometer, hydrophone (in water), or accelerometer.
• The propagation velocity of the waves depends on density and elasticity of the medium. Velocity tends to increase with depth and ranges from approximately 2 to 8 km/s in the Earth’s crust, up to 13 km/s in the deep mantle. The refraction or reflection of seismic waves is used for research into the structure of the Earth’s interior, and man-made vibrations are often generated to investigate shallow, subsurface structures.

12.C

• Secondary waves (S-waves) are shear waves that are transverse in nature. S-waves can travel only through solids, as fluids (liquids and gases) do not support shear stresses. S-waves are slower than P-waves, and speeds are typically around 60% of that of P-waves in any given material.
• Love waves are surface seismic waves that cause horizontal shifting of the Earth during an earthquake. They form a distinct class, different from other types of seismic waves, such as P-waves and S-waves (both body waves), or Rayleigh waves (another type of surface wave). Love waves travel with a lower velocity than P- or S- waves, but faster than Rayleigh waves.
• Rayleigh waves are part of the seismic waves that are produced on the Earth by earthquakes. They are a type of surface acoustic wave that travel on solids. They can be produced in materials in many ways, such as by a localized impact or by piezo-electric transduction, and are frequently used in non-destructive testing for detecting defects.

13.C

• The Crust is the outermost solid part of the earth. It is brittle in nature. The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental crust. The oceanic crust is basalt and the mean density of material in oceanic crust is 2.7 g/cm3.
• The outer core is in liquid state while the inner core is in solid state. At the centre of the earth at 6,300 km, the density value is around 13g/cm3. The core is made up of very heavy material mostly constituted by nickel and iron. It is sometimes referred to as the nife layer.

14.D

• Gravity anomalies give us information about the distribution of mass of the material in the crust of the earth. The gravity values differ according to the mass of material.
• The uneven distribution of mass of material within the earth influences this value. The reading of the gravity at different places differs from the expected values. Such a difference is called gravity anomaly.
• The gravitation force is not the same at different latitudes on the surface. It is greater near the poles and less at the equator. This is because of the distance from the centre at the equator being greater than that at the poles.

15.D

• Earth’s elemental composition reflects mostly heavier elements not blown away by solar wind during formation of the solar system. Most abundant elements are  Fe, O, Si, Mg and most common minerals consist of silica (SiO2 ) mixed in varying proportions with other elements such as Fe, Mg, Al, Ca, K, Na.
• The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental crust. The mean thickness of oceanic crust is 5 km whereas that of the continental is around 30 km. The continental crust is thicker in the areas of major mountain systems.

16.A

• The most easily available solid earth material is surface rock or the rocks we get from mining areas. Volcanic eruption forms another source of obtaining direct information. As and when the molten material (magma) is thrown onto the surface of the earth, during volcanic eruption it becomes available for laboratory analysis.
• Analysis of properties of matter indirectly provides information about the interior. Another source of information is the meteors that at times reach the earth. The material and the structure observed in the meteors are similar to that of the earth. They are solid bodies developed out of materials same as, or similar to, our planet. The other indirect sources include gravitation, magnetic field, and seismic activity.

17.D

• The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The changes in seismic velocity between different layers causes refraction owing to Snell’s law, like light bending as it passes through a prism.
• Secondary waves (S-waves) are shear waves that are transverse in nature. S-waves can travel only through solids, as fluids (liquids and gases) do not support shear stresses .S wave shadow zone form the boundary of outer core as it is in liquid state.

18.A

• The portion of the interior beyond the crust is called the mantle. The upper portion of the mantle is called asthenosphere. The word astheno means weak. It is the main source of magma that finds its way to the surface during volcanic eruptions. It has a density higher than the crusts.
• The crust and the uppermost part of the mantle are called lithosphere. Its thickness ranges from 10-200 km. Earthquake waves get recorded in seismographs located at far off locations. However, there exist some specific areas where the waves are not reported. Such a zone is called the ‘shadow zone’.

19.D

• Primary waves (P-waves) are compressional waves that are longitudinal in nature. P waves are pressure waves that travel faster than other waves through the earth to arrive at seismograph .These waves can travel through any type of material, including fluids, and can travel at nearly twice the speed of S waves.
• Secondary waves (S-waves) are shear waves that are transverse in nature. S-waves can travel only through solids, as fluids (liquids and gases) do not support shear stresses. S-waves are slower than P-waves, and speeds are typically around 60% of that of P-waves in any given material.

20.D

• Earth’s magnetic field extends from the interior to out into space, where it meets the solar wind, a stream of charged particles emanating from the Sun. The field of a magnetic dipole currently tilted at an angle of about 10 degrees with respect to Earth’s rotational axis.
• Earth’s magnetic field changes over time because it is generated by a geodynamo (in Earth’s case, the motion of molten iron alloys in its outer core).While the North and South magnetic poles are usually located near the geographic poles, they can wander widely over geological time scales.
• However, at irregular intervals, the Earth’s field reverses and the North and South Magnetic Poles relatively abruptly switch places. These reversals of the geomagnetic poles leave a record in rocks that are of value to paleomagnetists in calculating geomagnetic field’s .Such information in turn is helpful in studying the motions of continents and ocean floors.