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Q41. Calculate the degree(s) of freedom of the assemblage Opx + Cpx + Plag + Hbl + Qtz + Fluid in the 6-component system CaO-FeO-MgO-Al2O3-SiO2-H2O.
Phase Rule: F = C - P + 2. Components (C)=6. Phases (P)=6. F = 6 - 6 + 2 = 2.
Q42. Water content = 10%, Porosity = 25%, Specific Gravity = 2.5. Volume of water to add to 100 m3 of soil for full saturation (in m3)?
Porosity 25% means 25m3 voids per 100m3. Dry density = 2.5 * (1-0.25) = 1.875 g/cc. Mass dry = 187.5 tons. Current water (w=10%) = 18.75 tons = 18.75 m3. Pore volume = 25 m3. Water needed to fill pores = 25 - 18.75 = 6.25 m3.
Q43. On a photo-scale of 1:40,000, a square shaped open cast coal mine of 1 sq. km area would have an image area of (in sq. cm):
Scale ratio is 1/40,000. Area scale is (1/40,000)^2. 1 sq km = 10^10 sq cm. Image Area = 10^10 / 16*10^8 = 6.25 sq cm.
Q44. The following gamma ray (GR) log data are recorded: GR log = 30 API, Max GR = 45 API, Min GR = 20 API. What is the fraction of shale?
Shale fraction (Vsh) is calculated as (GR_log - GR_min) / (GR_max - GR_min). Calculation: (30 - 20) / (45 - 20) = 10 / 25 = 0.4.
Q45. It takes approximately how many seconds for sunlight to reach the Earth?
Sunlight takes about 8 minutes and 20 seconds to travel the distance from the Sun to the Earth.
Q46. The number of hydrous minerals in the Moh's scale of hardness is:
The Mohs scale contains two hydrous minerals: Gypsum (CaSO4ยท2H2O) and Talc (Mg3Si4O10(OH)2).
Q47. In Mohs' scale of hardness, how many minerals are of silicate composition?
The silicate minerals on Mohs scale are: Talc (1), Orthoclase (6), Quartz (7), and Topaz (8). The others are sulfates, carbonates, oxides, etc.
Q48. Core sample: 4cm dia, 35.81cm height, 1000g wet wt. Dry wt 866.25g. Average bulk density (g/cm3):
Total Volume = 450 cm3. Bulk Density = Total Mass / Total Vol = 1000 / 450 = 2.22 g/cm3.
Q49. A confined sandy aquifer has a thickness of 10 m and transmissivity of 0.75 sq. m/day. Its hydraulic conductivity is (m/day):
Transmissivity (T) = Hydraulic Conductivity (K) * Thickness (b). 0.75 = K * 10. K = 0.075 m/day.
Q50. A confined aquifer has thickness 10m and transmissivity 0.75 m2/day. Hydraulic conductivity is:
Transmissivity (T) = K * b. K = T / b = 0.75 / 10 = 0.075 m/day.