41. What is the key purpose of performing 2D resistivity imaging? A. Mapping vegetation B. Mapping weather conditions C. Mapping subsurface structure D. Locating wells Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C Solution: 2D resistivity imaging creates cross-sectional images showing variations in resistivity with depth and lateral distance.
42. Magnetic anomalies are best observed in areas with: A. High moisture B. Dense vegetation C. Ferromagnetic minerals D. Thick topsoil Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C Solution: Magnetic anomalies occur due to the presence of ferromagnetic materials like iron-rich rocks or ores.
43. What does Vertical Seismic Profiling (VSP) involve? A. Seismic measurements at the surface B. Seismic signals recorded in boreholes C. Recording wave reflections at faults D. Cross-hole tomography Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B Solution: VSP involves placing receivers down a borehole while the source is on the surface to get high-resolution seismic data near the borehole.
44. What is the main objective of electrical resistivity tomography (ERT)? A. Soil classification B. Groundwater sampling C. Subsurface resistivity mapping D. Temperature measurement Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C Solution: ERT is a geophysical imaging method that creates 2D or 3D models of the resistivity distribution underground.
45. The Bouguer correction in gravity surveys accounts for: A. Magnetic anomalies B. Instrument drift C. Elevation and terrain variations D. Electrical noise Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C Solution: The Bouguer correction adjusts gravity data for elevation and terrain effects to isolate true density anomalies.
46. Which geophysical method is used to measure variations in electrical potential due to subsurface features? A. Self-potential B. GPR C. Gravity D. Seismic Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A Solution: Self-potential (SP) measures natural electric potentials in the ground.It�s useful in identifying ore bodies, groundwater flow, and geothermal zones.
47. The travel time of seismic waves is primarily used to determine: A. Rock porosity B. Subsurface lithology C. Electrical conductivity D. Magnetic anomalies Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B Solution: Seismic travel time helps in mapping subsurface lithology by identifying boundaries based on changes in wave velocity.
48. What is the typical unit of magnetic field strength used in geophysical exploration? A. Newton B. Gauss C. Tesla D. Ampere Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B Solution: Magnetic field strength is usually expressed in Gauss or nanoTesla (nT), especially in exploration work.
49. The resolution of Ground Penetrating Radar depends on: A. Antenna frequency B. Soil density C. Temperature D. Magnetic field Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A Solution: GPR resolution improves with higher antenna frequency, though it reduces penetration depth.
50. What is the depth of investigation in resistivity methods most influenced by? A. Surface vegetation B. Electrode spacing C. Rock hardness D. Survey time Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B Solution: The electrode spacing directly influences how deep the resistivity current penetrates the subsurface.
