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Q141. During the northern hemispheric winter, the -16°C isotherm reaches its lowest latitude over:
Continental interiors like Siberia experience the most extreme winter cooling due to their distance from the moderating effects of the ocean.
Q142. Conditional instability is said to occur when the atmospheric lapse rate is:
Conditional instability occurs when the Environmental Lapse Rate is steeper than the Saturated (wet) Adiabatic lapse rate, but less steep than the Dry Adiabatic lapse rate.
Q143. Shortening in the Earth's crust is accommodated by:
Compressional stress (shortening) causes folding and reverse faulting. Normal faults accommodate extension.
Q144. Composite volcanoes are mainly made up of alternate bands of:
Composite volcanoes (stratovolcanoes) are characterized by steep profiles built from alternating layers of effusive lava flows and explosive pyroclastic materials (ash, pumice, and cinders).
Q145. The optically active substance that undermines the remote estimation of chlorophyll most is:
Coloured Dissolved Organic Matter (CDOM) strongly absorbs light in the blue wavelength region, which overlaps with the absorption spectrum of chlorophyll, confusing satellite sensors.
Q146. Compared to Delhi, Earth's normal gravity field at Colombo is:
Colombo is situated much closer to the equator than Delhi. Normal gravity decreases from the poles to the equator due to maximum centrifugal force and maximum equatorial radius at the equator.
Q147. Which of the following oceanic processes accounts for most of the Earth's sedimentary rocks containing phosphates?
Coastal upwelling brings cold, nutrient-dense (phosphate-rich) deep water to the surface. The resulting explosion in biological productivity and subsequent decay leads to massive phosphorite deposits on the seafloor.
Q148. The correct sequence of increasing coalification is:
Coalification increases with burial temperature and pressure, progressively transforming organic matter from Peat to Lignite, then to Bituminous coal, and finally to Anthracite.
Q149. The process of chemosynthesis differs from photosynthesis as it is:
Chemosynthesis utilizes chemical energy derived from the oxidation of inorganic compounds (like hydrogen sulfide) to produce organic matter, rather than using sunlight.
Q150. The mineral phases associated with biogenic, hydrogenic, and hydrothermal processes, respectively, are:
Carbonates are predominantly biogenic (shells/skeletons). Phosphorites are often hydrogenic (precipitating from seawater). Massive sulphides form through hydrothermal vent processes.