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Q101. The reflection coefficient at the interface between two layers of resistivities 9 ohm-m and 1 ohm-m respectively is (magnitude):
The reflection coefficient magnitude is |(P2 - P1)/(P2 + P1)| = |(1 - 9)/(1 + 9)| = |-8/10| = 0.8.
Q102. A coarse-grained igneous rock consists of 55% olivine, 25% augite and 20% enstatite. According to the IUGS classification, the rock is
The rock is ultramafic (>90% mafic minerals). With >40% olivine, it's a peridotite. Containing both clinopyroxene (augite) and orthopyroxene (enstatite) in significant amounts places it in the Lherzolite field.
Q103. Factors governing the inclination of the slip face of ripples:
The slip face (lee side) maintains the Angle of Repose, which is determined by the internal friction angle of the sediment grains.
Q104. In a region, given the palaeomagnetic inclination (I), the palaeolatitude (lambda) can be calculated using the formula:
The standard dipole equation relating inclination (I) to latitude (lambda) is tan(I) = 2 * tan(lambda).
Q105. Which marine environment is indicated by the benthic foraminifera Quinqueloculina, Ammonia, and Elphidium?
These genera are characteristic of shallow, high-energy Shelf or coastal lagoon environments. They do not inhabit deep ocean (Abyssal/Hadal) zones.
Q106. Why do Li, Be, and B have low cosmic abundance?
These light elements are consumed by nuclear fusion reactions (proton capture) in stellar interiors, a process called astration.
Q107. The acceleration due to gravity (g) and universal gravitational constant (G) are related by the expression (Me = mass of earth, Re = radius):
This is derived from Newton's Law of Universal Gravitation, where the force of gravity F = GMm/r^2 equates to weight F = mg.
Q108. The increase in the length of a day on the earth at a rate of 2.4 milliseconds/100 years is due to:
Tidal friction caused by the gravitational interaction between the Earth and Moon dissipates energy, gradually slowing Earth's rotation.
Q109. In which electromagnetic method is the rate of change of secondary field recorded?
Time-domain EM (TDEM) measures the decay of the secondary magnetic field (dB/dt) after the primary transmitter is switched off.
Q110. For horizontal flow in a saturated aquifer, the product of hydraulic conductivity (K) and thickness (b) is equal to:
Transmissivity (T) is defined as the rate at which water flows through a vertical strip of the aquifer: T = K * b.