(Download) UPSC: Geo-Scientist Main Papers-2021 (Geophysics Paper-II)


(Download) UPSC: Geo-Scientist Pre Papers-2021

(Geophysics Paper-II)


Exam Name : UPSC Geo-Scientist and Geologist Exam

Subject : UPSC Geo-Scientist and Geologist Exam Papers 2021 : Geophysics Paper- II

Year : 2021

Geophysics Paper - II

  • Time Allowed : Three Hours
  • Maximum Marks : 200

 

1. A particle with kinetic energy equal to on the surface of rotating earth will:

(a) Start rotating around the earth

(b) Escape from the earth

(c) Remain on the earth with maximum potential energy

(d) Reach the equator

2. A satellite is revolving round the earth at a height of 600 km. Considering the radius of the earth as 6400 km, the mass of the earth as 6 × 1024 kg and gravitational constant (G) as 6.67 × 10–11Nm2/kg2,the time period of the satellite will be:

(a) 4.8 × 103S

(b) 4.8 × 106S

(c) 5.8 × 103S

(d) 4.2 × 102S

3. The most studied and largest fraction of the meteorites recovered on the earth is:

(a) Achondrites

(b) Chondrites

(c) Iron

(d) Iron-stony

4. Which one of the following statements is true for planets revolving around the Sun?

(a) Areal velocity of different planets is different

(b) Areal velocity of a planet is not constant

(c) Only Earth has areal velocity

(d) Jupiter has the largest areal velocity

5. When the mass of a star becomes more than 1.4 times the solar mass, it would cease to be a:

(a) White dwarf

(b) Neutron star

(c) Black hole

(d) Pulsar 

6. Consider the following statements:
Statement-1: The earth’s gravity increases from equator to pole
Statement-2: The equatorial bulge places an excess mass at equator, which causes the decrease in gravity at the equator
Which one of the following is correct in respect of above statements?

(a) Both Statement-1 and Statement-2 are true and Statement-2 is the correct explanation of Statement-1

(b) Both Statement-1 and Statement-2 are true but Statement-2 is not the correct explanation of Statement-1

(c) Statement-1 is true but Statement-2 is false

(d) Statement-1 is false but Statement-2 is true

7. The geostationary orbit of a satellite around the earth is such that the satellite remains stationary with respect to the earth. It requires that the orbit must be:

a) Geosynchronous, elliptical with height from the surface of earth nearly 36,000 km

b) Geosynchronous, circular with height from the surface of earth nearly 36,000 km

c) Geosynchronous, circular and stays over the geographical poles of earth at a height of nearly 36,000 km

d) Geosynchronous, orthogonal above the south pole at a height of nearly 36,000 km

8. Major component of earth’s magnetic field comes from:

(a) Core

(b) Crust

(c) Mantle

(d) Ionosphere

9. Which one of the following properties always exists in presence of magnetic field?

(a) Ferromagnetism

(b) Paramagnetism

(c) Antiferromagnetism

(d) Diamagnetism

10. Which one of the following statements regarding earth’s magnetism is true?

(a) A freely suspended magnet will be vertical at the equator

(b) Magnetic meridian at a place is a line passing through the axis of a freely suspended magnet

(c) At poles, the angle of dip is 0° and horizontal component of earth’s magnetic field is also zero

(d) Lines joining the points of same declination on the earth surface are called isogonic lines

11. Consider the following statements regarding Magnetometer:
1. Proton Precession Magnetometer (PPM) is a total field magnetometer
2. PPM uses magnetizing solenoid
3. PPM can measure field components
4. Flux-gate Magnetometer measures components of the magnetic field along its axis
Which of the statements given above are correct?

(a) 1, 2 and 4

(b) 1, 2 and 3

(c) 1, 3 and 4

(d) 2, 3 and 4

12. Geostrophic winds:

(a) Are real winds that blow parallel to the lines of equal temperature

(b) Exist between the horizontal components of the coriolis force and the vertical pressure gradient force

(c) Are hypothetical winds that blow parallel to the lines of equal pressure

(d) Represent to the actual winds at elevations lesser than 800 m

13. A solution u = cos (at) sin (????) satisfies the wave equation: . The value of constants (a, b and c) can be related as:

(a) ??2 = ??2 ??2

(b) ??2 ??2??2 = 1

(c) ??2 = ??2??2

(d) ??2 = ??2 ??2

14. Which one of the following statements regarding longitudinal waves is NOT CORRECT?

(a) These can travel through fluids

(b) These are compressional waves

(c) These are also known as primary waves

(d) Motion of the particles is perpendicular to the direction of wave propagation

15. The shear wave will be essentially elliptically polarized when:

(a) Both SH and SV motions have different frequencies

(b) Both SH and SV motions have varying phase difference

(c) Both SH and SV motions have same frequency and fixed phase difference

(d) Both SH and SV motions have same amplitude 

16.During convergent motion of the oceanic and continental plates, continental plate rides higher because:

(a) It is denser and thinner than the oceanic crust

(b) It is less dense and thicker than oceanic crust

(c) It is denser and thicker than oceanic crust

(d) It is less dense and thinner than oceanic crust

17. The P-wave velocities of more than 8 km/s beneath Moho discontinuity indicate the presence of:

(a) Granite and gabbro

(b) Granite and basalt

(c) Basalt, gabbro and granite

(d) Rocks rich in dense minerals like olivine, pyroxene and garnet

18. Which one of the following statements regarding velocity variations inside the earth is correct?

(a) Low velocity zone exists between 100–250 km depth

(b) Velocities decrease with depth

(c) Velocities decrease dramatically at 660 km depth

(d) P-wave velocities decrease at the boundary between liquid outer core and solid inner core

19. The continuous movement of tectonic plates result in earthquakes. The point inside the earth from which earth shock waves generate is called:

(a) Seismic focus

(b) Epicentre

(c) Richter centre

(d) Trigger centre

20. Which one of the following statements regarding tectonic earthquakes is correct?

(a) These are randomly distributed over the globe

(b) These are the abrupt release of strain within the earth

(c) They only occur on or near the plate boundaries and not within the lithospheric plates

(d) The result from the motion of underground magma

21. Which one of the following statements is correct with reference to the geosyncline?

(a) It is a linear part of the crust of earth that sagged widely through time

(b) It is a linear part of the crust of earth that sagged deeply through time

(c) It is not linked with the origin of mountains

(d) Generally, it is few kilometers long and hundreds of kilometers wide

22. Teleseismic events have an epicentral distance of:

(a) Greater than 200

(b) Less than 200

(c) Less than 50

(d) Less than 10

23. The energy released by an earthquake of magnitude 7 will be approximately equal to energy released by:

(a) 1000 earthquakes of magnitude 5

(b) 100 earthquakes of magnitude 5

(c) 500 earthquakes of magnitude 5

(d) 110 earthquakes of magnitude 5

24. If ?? = ???? + yj + zk, then, what is the divergence of (rn r)?

(a) (3 – n) rn

(b) (3 + n) r–n

(c) (3 + n) r2

(d) (3 + n) rn

25. Two constant forces F1 = (2i + 3j + 3k) Newton and F2 = (5i – 6j – 2k) Newton act together on an object during its displacement from the point (20i + 15j) meter to a point 8k meter. What is the amount of work done on the particle?

(a) – 28 Joule

(b) – 87 Joule

(c) – 46 Joule

(d) – 62 Joule

26. The possible eigen values of given matrix M are:

27 . Which one of the following correctly gives the value of determinant of a (4 × 4) diagonal matrix (1, 2, 4, –6)?

(a) 1

(b) 48

(c) – 48

(d) – 1

28. Which one of the following statements regarding gravitational forces is NOT true?

(a) It is always attractive

(b) It is a conservative force

(c) It depends on the medium between the particles

(d) It is a long range force

29. A satellite of mass m is in geosynchronous orbit around the earth of mass M and angular velocity ω. What is the radius of the geosynchronous orbit?

(a) √(GM/ω2)

(b) GM/ω2

(c) (GM/ω2)1/3

(d) (GM/ω2)1/4

30. If strength of strong force is 1, then what is the relative strength of electromagnetic force?

(a) 10–37

(b) 10–2

(c) 102

(d) 1037

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