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Q121. Which one of the following tectonic plates has the maximum average velocity?
The correct answer is Pacific. The Earth's crust is cracked into moving plates. The giant Pacific plate, surrounded by a violent 'Ring of Fire' (subduction zones), is famously the fastest-moving tectonic plate on Earth, racing along at roughly 7 to 10 centimeters every single year. The massive Eurasian, African, and North American continental plates are sluggish by comparison, mostly creeping along at just 1 to 2 centimeters a year.
Q122. A trench is found at a
The correct answer is convergent plate boundary. An oceanic 'trench' is a massive, deep topographic depression formed strictly at convergent plate boundaries, where one dense tectonic plate crashes into and subducts (dives) underneath another lighter plate. Divergent boundaries create raised mid-ocean ridges. Transform boundaries cause lateral sliding, and passive margins have no active plate collisions.
Q123. A volcanic rock consisting of alkali feldspar (70%), sodic plagioclase (10%) and nepheline (20%) is named as
The correct answer is Phonolite. Geologists classify rocks based on mineral percentages. Because this rock is mostly alkali feldspar (70%) and contains a very significant chunk of nepheline (a 'feldspathoid' mineral replacing quartz), the classification strictly designates it as a 'Phonolite'. A Trachyte is similar but lacks the high nepheline content, and Andesite and Tephrite have entirely different plagioclase-dominated chemistries.
Q124. Approximately 71% of the planetary mass in the solar system is concentrated in
The correct answer is Jupiter. Jupiter is truly a gas giant of unimaginable size. It is so massive that if you took every other planet, moon, and asteroid in the entire solar system and combined them together, Jupiter would still be vastly heavier than all of them combined. It dominates the solar system's planetary weight, holding over 70% of it by itself.
Q125. Atoll is a geomorphic feature formed by
The correct answer is coral reef accumulation. An 'atoll' is a beautiful, ring-shaped tropical island made entirely of coral reefs surrounding a central lagoon. It forms when a volcanic island slowly sinks into the ocean, and the corals keep growing upwards on top of themselves to stay in the sunlight, leaving a ring of coral rock. It has absolutely nothing to do with grinding ice (glaciers), wind, or river dirt (fluvial).
Q126. Choose the correct statement:
The correct answer is Coarse sands have high porosity and high permeability. Coarse beach sand is composed of large, chunky grains. This means it contains a huge amount of empty space between the grains to hold water (high porosity), and because the gaps are large, water flows through them incredibly fast and easily (high permeability). Clay is highly porous but practically impermeable, and weathered granite is far more porous than solid crystalline granite.
Q127. Evidence of Late Paleozoic glaciation is recorded in
The correct answer is Talchir Formation. About 300 million years ago, India was located near the South Pole and was covered in a massive ice sheet. The 'Talchir Formation' (the oldest layer of the Gondwana rocks) is geologically famous for preserving direct evidence of this deep freeze, containing massive glacial tillites and rocks dropped by melting icebergs (dropstones). The other formations came later when the climate had warmed into swamps and rivers.
Q128. Hardness of groundwater is determined by
The correct answer is concentrations of calcium and magnesium. When plumbers or geologists talk about 'hard water', they are not measuring physical rock hardness using the Mohs scale. Instead, water hardness is strictly a chemical measurement of how many dissolved mineral salts—specifically calcium and magnesium—are floating invisibly in the groundwater. Bernoulli and Darcy's laws deal with water physics and flow speed, not chemistry.
Q129. Identify the fold in the given figure, where T0 and Tα represent the axial plane thicknesses at the hinge and limb, respectively. (Image shows T0 = 5 cm and Tα = 5 cm)
The correct answer is Similar fold. According to Ramsay's mathematical fold classification, if you measure the thickness of a folded rock layer strictly along lines parallel to the axial plane, and that thickness stays exactly identical everywhere (T0 = Tα = 5 cm), it is officially categorized as a Class 2 'Similar fold'. A Parallel fold maintains its perpendicular thickness, not its axial planar thickness.
Q130. Identify the type of fault in the given figure. (Image shows the right-hand block sliding downwards along a slanted fault plane)
The correct answer is Normal fault. In the block diagram provided, the rock mass resting on top of the slanted fault plane (the hanging wall) has clearly slid downwards relative to the block underneath it (the footwall). This specific gravity-driven, downward-sliding motion caused by tectonic pulling (extension) is the exact textbook definition of a Normal fault.