Geo Physical Methods of Exploration-Quiz

PES103: Geophysical Exploration Methods

                                   Question Bank

1.      Age of Earth (in billion yrs)

    (a) 7

    (b) 9

    (c) 4.5

    (d) 11.0

                    

2.   Oceans constitute how much percentage of earth’s surface?

(a) 90%

                     (b) 30%

                     (c) 71%                                                                               

                     (d) 50%

3.   Gravitational Constant ‘G’ is equal to

         (a) 9.5*10^(-11) m3/kg^(-1) s^(-2)

         (b) 8.5*10^(-3) m3/kg^(-1) s^(-2)

         (c) 6.6*10^(-11) m3/kg^(-1) s^(-2) 

         (d) 6.67*10^(-2) m3/kg^(-1) s^(-2)

               

4. Crust-Mantle boundary is called

     (a) Gutenberg

     (b) Cornard

     (c) Moho

     (d) Newton

5. Average thickness of Lithosphere below Continents (km)

    

(a)    400

(b)   300 

(c)    250

(d)   550

6. The part containing Crust and upper mantle is called

(a)     Upper Crust               (b) Lower Crust 

(b)    Asthenosphere          (d) Lithosphere

                    7. Radius Of Earth is approx (kms)

               

                           (a) 8000    (b) 9000   (c) 1576   (d) 6378

                    8. Mid Oceanic ridges are oceanic features where

 

(a)    Continents Collide                                            

(b)   Continents Subside

(c)    New Magma comes out on to the ocean floor  

(d)   Oil Occurs

                    

                     9. Average thickness of Oceanic Crust

                      

(a)    1-2 kms  (b) 2-3 kms (c) 5-12 kms  (d) 25-50 kms

           10. Geophysical methods can be classified into two major categories as

                

(a)    Oil and Mineral prospecting methods

(b)   Detailed and Non-Detailed methods

(c)    Passive and Active Methods             

(d)   Less and More expensive methods

          11. A Pendulum measures

               

(a)     Gravity Constant                   (b) Relative gravity at a place

(c) Absolute gravity at a place    (d) Gravitational Constant

          12.Sediment Densities are

                (a) Lower than for Volcanic rocks    (b) Higher than for Volcanic rocks

                (c) Negligible                                    (d) Not Measurable

         13. Gravitational Constant ‘G’ is

        

             (a) Non-Measurable quantity

 (b) The force of attraction between two unit masses separated by a unit distance

             (c) Equal to ‘g’ at all places

             (d) Arbitrary Constant

       14. The major difference between Gravitational and Magnetic field is

(a)    Gravity is equal at all places

(b)   Gravity field is a scalar field and Magnetic field is a Vector field

(c)    Gravity can be measured at any place compared to magnetic

(d)   None of the above

       15. Geoid is

(a)    An imaginary line passing through earth

(b)   A reference used for gravity measurements

(c)    An equipotential surface over which the gravitational field is equal

(d)   None of the above  

       16. Gravity field is maximum at poles because

            

(a)    Polar ice Caps

(b)   High density

(c)    Excess mass

(d)   Due to flattening of earth and earth’s centrifugal force

       17. The Unit of gravity field in prospecting is

(a)    Gal

(b)   Gm/sec^2

(c)    Km/hr

(d)   Milligal

     18. Unit of magnetic field in prospecting

(a)        Magma

(b)       Gm/cm3 

(c)        Gamma

(d)       Oersted

    19. IGRF represents

(a)    International Geographic Reference Force

(b)   International Geomagnetic Reference Field

(c)    International Geomagnetic Resources Forum

(d)   None of the above

    20. The important mineral, which contributes to magnetic suspectabilities in rocks, is

(a)    Sphalarite

(b)   Sulphides

(c)    Magnetite

(d)   Manganese

    21. Polar radius of earth is

(a)    Lesser than equatorial radius

(b)   Higher than equatorial radius

(c)    Equal to the equatorial radius

(d)   None of the above

   22. The two important factors that influence density in shallow subsurface are

 

(a)    Chemical Composition and water constant

(b)   Width and Depth

(c)    Thickness and Dip

(d)   Porosity and Pore fluid content

   23. Earth’s normal Gravity

(a)    Increases with elevation

(b)   Decreases with elevation

(c)    Does not vary with elevation

(d)   None of the above

   24. Topographic and Bouger Corrections account for

        

(a)    Gravity field due to latitude changes

(b)   Gravity field due to tides

(c)    Gravity effect of the material between the Geoid and the ground surface

(d)   None of the above

  25. Gravimeter measures

(a)    Absolute gravity

(b)   Relative gravity

(c)    Gravitational constant

(d)   Geoid variations

  26. International Gravitational Formula gives

(a)    Variations of gravity with Latitude

(b)   Variations of gravity with Longitude

(c)    Variations of Geoid Level

(d)   None of the above

 27. The permanent magnetization acquired by a rock at the time of its origin is called

(a)    Original Magnetization

(b)   Induced Magnetization

(c)    Artificial Magnetization

(d)   Remanent Magnetization

 28. The Major contribution for earth’s magnetic field is

(a)    Of external origin

(b)   Due to Solar radiation

(c)    Diurnal variations

(d)   Circulation of convection currents within the inner core

 29. Magnetic Inclination at equator is

(a)    0°

(b)   90°

(c)    30°

(d)   45°

 30. The angle (D) between Magnetic Meridian and Geographic north can be

(a)   Always positive

(b)  Always negative

(c)   Always less than 30°

(d)  Positive or negative

 31. Magnetic Storms

(a)  Can be corrected using  mathematic formulae

(b) Cannot be corrected

(c)  Can be predicted and effect removed

(d) None of the above

 32. Stainless Steel is

(a)  A Source of very high magnetic anomaly

(b) A Source for remanent magnetization

(c)  Associated with a weak magnetic susceptibility

(d)  None of the above

 33. The Precessional frequency of proton in a magnetometer is

(a)    A measure of earth’s magnetic field at that place

(b)   Inversely proportional to the amplitude of the field

(c)    Represents the raise due to external sources

(d)   None of the above

 34. Magnetic and gravity interpretation methods can be broadly categorized as a

 

(a)    Ambiguous and Unique methods

(b)   Direct and Indirect methods

(c)    Relative and Unique methods

(d)   None of the above

 35. SP method measures

(a)    S and P waves

(b)   Natural self-potentials below the ground due to conducting ore bodies

(c)    Slope parameters in Seismic Surveys

(d)   None of the above

  36. Resistivity of a material is

(a)    Its ability to withstand external forces

(b)   A measure of its ability to oppose the flow of electrical current through its volume

(c)    Its resistance against induced magnetic field

(d)   None of the above

 37. SP anomalies are generally

(a)    Negative over ore bodies

(b)   Positive over ore bodies

(c)    Symmetric above ore bodies

(d)   Absent over the ore bodies

38. Electromagnetic Surveys give better results

(a)    If the top surface layer is more conductive

(b)   If the top surface layer is less conductive

(c)    If the top surface layer is highly magnetic

(d)   None of the above