# Indian Institute of Technology Guwahati (IIT-G) 2006 JAM Geophysics - Question Paper

JAM 2006 Geophysics

Full ques. Paper in attachment

GEOPHYSICS TEST PAPER

IMPORTANT NOTE FOR CANDIDATES

Select any Two Sections. Attempt ALL objective a nd subjective questions of the same Two Sections. Questions 1- 45 (objective questions) carry three marks each and questions 46 -66 (subjective questions) carry fifteen marks each.

Write the answers to the objective questions in the Answer Table for Objective Questions provided on page 17 only)

1. Plutonic equivalent of Trachyte is

(A) diorite

(B) gabbro

(C) granite

(D) syenite

2. The river meanders at the mature stage with gentle gradient. The formation of pointbar will be on:

(A) outer zone of the bend

(B) inner zone of the bend

(C) straight channel segment

(D) steep bank of the channel.

3. Match the features in Group 1 with the agents responsible for these features from Group 2

Group 1 Group 2 | ||||||||||||||||

| ||||||||||||||||

Choose the correct answer from the following: |

(A) P-4, Q-3, R-1, S-2

(b) P-2, Q-1, R-3, S-4

(c) P-3, Q-1, R-4, S-2

(D) P-1, Q-2, R-4, S-3

4. The area bounded by two fault planes dipping away from each other with hanging walls going downward is called as:

(A) dome

(B) grabben

(C) horst

(D) klippe

Group 1 |
Group 2 | |

P. |
axial plane is horizontal 1. |
Isoclinal fold |

Q. |
hinges are sharp and angular 2. |
Parallel fold |

R. |
limbs are parallel 3. |
Recumbant fold |

S. |
thickness of bed remains constant 4. |
Cheveron fold |

Choose the correct answer from the following: | ||

(A) |
P-2, Q-4, R-2, S-1 | |

(B) |
P-1, Q-3, R-2, S-4 | |

(C) |
P-4, Q-2, R-1, S-3 | |

(D) |
P-3, Q-4, R-1, S-2 |

6. Which of the following rock indicates initiation of metamorphism

(A) phyllite

(b) schist

(C) shale

(D) slate

7. Barrovian metamorphism of pelitic rocks is characterized by the first appearance of index minerals in a particular sequence. Which one of the following is the correct sequence.

(A) chlorite-garnet-biotite-kyanite-staurolite-sillimanite

(B) garnet-biotite-chlorite-staurolite-sillimanite-kyanite

(C) chlorite-biotite-garnet-staurolite-kyanite-sillimanite

(D) biotite-chlorite-garnet-kyanite-staurolite-sillimanite

8. A crystal has three crystallographic axes of 2 fold symmetry and mirror plane perpendicular to each of these crystallographic axes. The Herman-Manguin notation for crystal would be

(A) 2/m 2/m 2/m

(b) 2m

(C) 2mm

(D) 23

9. Indicate the correct order in terma of increasing Si : O ratio.

(A) phlogopite-beryl-plagioclase-epidote

(B) epidote-beryl-phlogopite-plagioclase

(C) beryl-phlogopite-plagioclase-epidote

(D) plagioclase-phlogopite-epidote-beryl

10. Sandstones and purple shales of Muree Series of Potwar region, equivalent to Dagshai and Kasauli beds of northwest Himalaya belongs to

(A) Upper Eocene

(B) Lower Eocene

(C) Middle Miocene

(D) Lower Miocene

11. A radiogenic isotope has half-life of 1 hour and we have 10000 atoms of that particular isotope in a particular system at a particular time. How much atoms of that isotope will be there after 6 hours?

(A) 78

(B) 156

(C) 313

(D) 625

12. Find the odd man out from the following

(A) stockwork

(B) ladder vein

(C) saddle reef

(D) banding

13. Sulfide chimneys are observed at

(A) vents of seafloor hotsprings around ridges

(B) inland hotspring vents in volcanic terrains

(C) sulfide mineral coatings on the chimneys of smelters

(D) mouths of explosive volcanoes

14. Within the mantle sudden density change produce seismic-wave discontinuities due to polymorphic transition or compositional change or a combination of both occur at a depth of

(A) 470 kms

(b) 570 kms

(c) 670 kms

(d) 760 kms

15. The estimated thickness of the moons lithosphere is about

(A) |
35 km |

(B) |
65 km |

(C) |
100 km |

(D) |
1000 km |

16. In case of an inelastic collision which one of the following is true

(A) Total energy is not conserved

(B) Momentum is not conserved

(C) Kinetic energy is conserved

(D) Kinetic energy is not conserved

17. The root mean square speed of an ideal gas, made up of molecules of molecular weight

0 0831 kg/mol, at temperature 300 K is (Take universal gas constant R = 8 31 J/mol K)

(A) |
100 |
m/s |

(B) |
200 |
m/s |

(C) |
300 |
m/s |

(D) |
400 |
m/s |

engines A and B are the same. If the ratio of the respective efficiencies,

to 2 then the ratio of the hot reservoir temperatures

is equal

n

is

(A) 0 25

(B) 0 5

(C) 1 0

(D) 2 0

19. Which one of the following phenomenon cannot be described by the particle nature of electromagnetic radiations.

(A) Blackbody radiations

(B) Compton scattering

(C) Photoelectric effect

(D) X-ray diffraction

20. If a semiconductor is doped with donor atoms then the impurity levels created in the semiconductor are close to the

(A) bottom of the conduction band

(B) top of the valence band

(C) bottom of the valence band

(D) top of the conduction band

21. Binding energy per nucleon for the nuclei ^{4}He, ^{56}Fe, ^{197}Au and ^{235}U are given by B_{1;} B_{2}, B_{3} and B_{4}, respectively. These binding energies satisfy the order

(A) B1< B2 < B3 < B4

(B) B1> B2 > B3 > B4

(C) B_{2} < B_{3} < B_{4}< B_{1}

(D) B_{2} > B_{3} > B_{4}> B_{1}

22. When a thin transparent sheet is introduced along the path of one of the slits in Youngs double slit experiment, then the fringe width

(A) decreases

(B) increases

(C) does not change

(D) does not change but intensity becomes half

23. An infinite wire, lying along the z -axis, carries a current I in the positive z direction denoted by k. The magnetic field at a point d i is M0^{1}

(B)

J

2nd

M0^{1} j 2nd

V0^{1} j 2nd

M0^{1} j 2nd

The radius of curvature of curved surface of a plano-convex thin lens of glass (refractive index n = 1 5) of focal length 0 4 m is

24.

(A) 0 1 m

(B) 0 2 m

(C) 0 4 m

(D) 0 8 m

The engine of a train, emitting the sound of frequency v_{0} approaches an observer with constant speed. If the observer measures the frequencies as v_{1} when it is approaching and v_{2} while it is going away, the relation between the frequencies is given by

25.

^{(A) V}1 = ^{V}2 = ^{V}0

(B)

^{V}1 > ^{V}0 > ^{V}2

(C)

^{V}1 < ^{V}0 < ^{V}2 ^{V}1 = ^{V}2 * ^{V}0

(D)

In a dielectric sphere the polarization P is given by P = kr^{3}r . The corresponding bound volume charge density is equal to

26.

(A) - 20 k

(B) -10 k

(C) 10k

(D) 20k

An ideal fluid is flowing through a tube of cylindrical cross section with smoothly varying radius. The velocity of fluid particles at the point where tubes cross sectional area is 1x 10^{-4} m^{2} is given by 0.01 m/s. The velocity at a point where cross sectional area is

27.

2 x 10^{-4} m^{2} is given by

(A) 0 0025 m/s

(B) 0 005 m/s

(C) 0 02 m/s

(D) 0 04 m/s

28. The solution of Maxwells equation for electric field in free space is given by E = E_{0}sin(t - x / c), where E_{0} is a constant, a> is the angular frequency and c is the speed of light. The corresponding solution for the magnetic field B is

(A) B = cE_{0}sin(t - x / c)

_{E}

(B) B =-sin(t - x / c)

c

E

(C) B =2-sina(t - x / c)

c

_{E}

(D) B = 0sin(t - x / c)

c

The frequency of electron in n = 1 Bohr orbit is given by frequency of electron in the n -th orbit for n >1 is

/ revolutions/s. The

29.

(A)

(B)

^{/}1^{/ }n

/j/ n^{2}

(C) fj n3

^{(D) nf1}

A signal of 1 mV is input to an amplifier circuit consisting of a transistor in common-emitter mode. What is the voltage gain if the collector current changes by 1 mA and the load resistance is equal to 1 kQ?

30.

(A) 10

(B)

10^{2}

10^{3}

(C)

(D)

10^{4}

31. Let a_{n}, a_{n} > 0 be a convergent series. Now, consider the following statements:

n>1

P: The series is always convergent.

^{1} 2 n

Q: The series

is always divergent.

n

}

Then,

(A) both P and Q are true

(B) P is true and Q is false

(C) both P and Q are false

(D) P is false and Q is true

+| x - | , if x is rational

^{f}(x) =

if x is irrational.

2

Then,

(A) f is continuous and differentiable only at x=

(B) f is continuous only at x = 2 but not differentiable at x

(C) f is neither continuous nor differentiable at x =

(D) f is continuous and differentiable for every x = [0,1]

dz

where C = {z : | z - i

^{1 is}

^{(z} -^{i) (z} +^{i)}

33. The value of the integral j)

(A)

(B)

(C)

(D)

1

n

n . i 2

ni

1 x y

34. The integral US f (x, y, z) dzdydx is equal to

0 0 0

i x x

(A)

(B)

(C)

(D)