1.
What is the Formation Factor, given the resistivity of the matrix as 100 ohm-m and the resistivity of water as 20 ohm-m?
Correct Answer
D. 5
Explanation
The Formation Factor is calculated by dividing the resistivity of the matrix by the resistivity of the water. In this case, the resistivity of the matrix is 100 ohm-m and the resistivity of the water is 20 ohm-m. Therefore, the Formation Factor is 100/20 = 5.
2.
In a 4-layer subsurface model, which combination of A-, H-, K-, and Q- type electrical resistivitysounding curves is NOT possible
Correct Answer
C. HQ
Explanation
In a 4-layer subsurface model, the combination of HQ type electrical resistivity sounding curves is not possible. This is because the H-type curve represents a high resistivity layer, while the Q-type curve represents a low resistivity layer. These two types of curves are contradictory and cannot exist together in the same model.
3.
For three-layered earth with resistivities ρ1, ρ2, and ρ3, and corresponding thicknesses h1, h2, and
h3 respectively, the quantity (h1/ρ1) + (h2/ρ2) + (h3/ρ3) stands for
Correct Answer
B. Longitudinal Conductance
Explanation
The quantity (h1/ρ1) + (h2/ρ2) + (h3/ρ3) represents the longitudinal conductance. This is because conductance is the reciprocal of resistance, and the given expression involves the sum of thicknesses divided by resistivities. Conductance is a measure of how easily electric current can flow through a material, and in this case, it represents the combined conductance of the three layers of the earth.
4.
The resistivity of conducting metallic sulfides vary from:
Correct Answer
C. 0.00001 to 0.1 ohm-m
Explanation
The resistivity of conducting metallic sulfides varies from 0.00001 to 0.1 ohm-m. This means that different metallic sulfides can have resistivities within this range. It suggests that metallic sulfides can have relatively low resistivity values, which indicates their ability to conduct electricity efficiently. The range provided also implies that there can be variations in the conductivity of different metallic sulfides, with some being more conductive than others.
5.
Resistivity Profiling and sounding are taken at __________ angle to the strike, respectively.
Correct Answer
A. 90 degree and 0 degree
Explanation
Resistivity profiling is taken at a 90-degree angle to the strike because it provides a cross-sectional view of the subsurface, perpendicular to the strike direction. This allows for a comprehensive understanding of the resistivity variations at different depths. On the other hand, resistivity sounding is taken at a 0-degree angle to the strike, which means it is parallel to the strike direction. This method provides information about the resistivity variations along a single line, helping to determine the lateral continuity of subsurface layers.
6.
The formation factor is related to :
Correct Answer
C. Porosity of Rock
Explanation
The formation factor is a measure of the ability of a rock formation to transmit electrical current. It is directly related to the porosity of the rock, which is the measure of the volume of voids or openings in the rock. A higher porosity indicates a higher formation factor, meaning that the rock has more voids and can allow for better electrical conductivity. Therefore, the formation factor is related to the porosity of the rock.
7.
The limiting depth of electrical sounding is :
Correct Answer
D. More than 10 km
Explanation
The limiting depth of electrical sounding refers to the maximum depth that can be accurately measured using this method. In this case, the correct answer is "more than 10 km," indicating that electrical sounding can accurately measure depths greater than 10 kilometers.
8.
The shape of a VES curve over a three-layer sequence comprising: moist soil (top), freshwater saturated coarse sand (middle), and Clay (bottom) is:
Correct Answer
C. K Type
Explanation
The correct answer is K Type. The K Type VES curve represents a three-layer sequence with moist soil on top, followed by freshwater saturated coarse sand in the middle, and clay at the bottom. In this type of curve, there is a sharp increase in resistivity from the moist soil to the freshwater saturated coarse sand, indicating a change in lithology. The resistivity then decreases significantly when reaching the clay layer due to its high conductivity. This pattern is characteristic of the K Type curve.
9.
The electrical conduction mechanism in Sedimentary rocks is usually :
Correct Answer
C. Electrolytic
Explanation
The electrical conduction mechanism in sedimentary rocks is usually electrolytic. This means that the rocks can conduct electricity through the movement of ions within their structure. This is different from electronic conduction, which involves the movement of electrons. Sedimentary rocks are composed of various minerals and can contain water or other fluids within their pore spaces. These fluids can act as electrolytes, allowing for the flow of ions and the conduction of electricity.
10.
Which electrode configuration has the maximum depth of investigation for homogeneous earth ????
Correct Answer
B. Two electrode
Explanation
The two-electrode configuration has the maximum depth of investigation for homogeneous earth. This is because in this configuration, one electrode is used to inject current into the ground, while the other electrode is used to measure the potential difference. This setup allows for a deeper penetration of the electric field into the earth, resulting in a greater depth of investigation. In contrast, the three-electrode configuration and the Wenner and Schlumberger configurations involve multiple electrodes, which can limit the depth of investigation.
11.
Which 4-electrode configuration is best suited to Archaeological Investigations ???
Correct Answer
A. Pole Pole
Explanation
The Pole Pole 4-electrode configuration is best suited for Archaeological Investigations. This configuration involves placing two current electrodes close together and two potential electrodes further apart. This setup allows for a deeper penetration into the ground, making it ideal for detecting buried archaeological features or structures. Additionally, the Pole Pole configuration provides good resolution and can accurately map the subsurface, helping archaeologists locate and identify potential archaeological sites.
12.
The Principle of Reciprocity is applicable for both homogeneous and non-homogeneous earth.
Correct Answer
A. True
Explanation
The Principle of Reciprocity states that the response of a system to a source depends only on the relative position of the source and the receiver. This principle is applicable to both homogeneous and non-homogeneous earth because it focuses on the relative positions and does not consider the specific characteristics of the medium. Therefore, whether the earth is homogeneous (uniform composition) or non-homogeneous (varying composition), the Principle of Reciprocity can still be applied to analyze the response of the system.
13.
The resistivity of acidic igneous rocks is less than the resistivity of basic igneous rocks.
Correct Answer
B. False
Explanation
The resistivity of acidic igneous rocks is not necessarily less than the resistivity of basic igneous rocks. The resistivity of a rock depends on various factors such as its composition, porosity, and moisture content. While it is true that some acidic igneous rocks may have lower resistivity due to their higher water content, it is not a general rule. Similarly, some basic igneous rocks may have lower resistivity depending on their specific characteristics. Therefore, it is incorrect to say that the resistivity of acidic igneous rocks is always less than that of basic igneous rocks.
14.
The resistivity along a bedding plane is less than the resistivity across it.
Correct Answer
A. True
Explanation
The resistivity along a bedding plane is less than the resistivity across it because the bedding plane typically consists of loosely packed sediments or fractures that allow for easier flow of electrical current. This results in a lower resistance along the bedding plane compared to the resistance across it, where the current has to traverse through a greater distance of rock or material with higher resistivity.
15.
Which electrode configuration acquires maximum vertical resolution?
Correct Answer
D. Wenner
Explanation
The Wenner electrode configuration acquires maximum vertical resolution because it has the largest electrode spacing compared to the other options. This larger spacing allows for better depth penetration and the ability to detect subtle changes in the subsurface. The Schlumberger configuration has the smallest spacing, resulting in lower vertical resolution. The Pole Dipole and Half Wenner configurations have intermediate spacing and therefore lower vertical resolution compared to the Wenner configuration.
16.
The value of coefficient of anisotropy lies between generally:
Correct Answer
A. 1 to 2
Explanation
The coefficient of anisotropy measures the degree of anisotropy or the extent to which a material's properties vary with direction. A value between 1 to 2 suggests that the material is moderately anisotropic, meaning that its properties vary significantly with direction but not to an extreme extent. This range indicates that the material has some level of directionality in its properties, but it is not highly directional or isotropic (uniform in all directions).
17.
The electrical Resistivity Method is generally used :
Correct Answer
B. In engineering and groundwater investigations
Explanation
The electrical Resistivity Method is commonly used in engineering and groundwater investigations. This method involves measuring the electrical resistivity of subsurface materials to determine their composition and properties. It helps in identifying the presence of underground structures, such as faults or fractures, which can be crucial in engineering projects. Additionally, the resistivity method is used to locate groundwater resources and assess their quality and quantity. By analyzing the resistivity data, geologists and engineers can make informed decisions about the feasibility and design of construction projects and effectively manage groundwater resources.
18.
The order of resistivity of clay is :
Correct Answer
B. 100 ohm-m
Explanation
It generally has the range 1-100 ohm-m