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Q1. Incongruent dissolution of orthoclase in a humid climate weathering profile will result in the formation of:
When orthoclase feldspar weathers chemically via hydrolysis (incongruent dissolution), it typically breaks down into the clay mineral kaolinite, releasing dissolved silica (silicic acid) and potassium ions.
Q2. Which one of the following most completely explains the breakdown process of biotite during initial weathering?
Weathering of biotite involves the leaching of highly mobile Potassium (K) ions from the interlayers and the oxidation of Iron from Fe2+ to Fe3+.
Q3. Ocean temperature anomalies last longer than atmospheric temperature anomalies because ocean water:
Water has a much higher specific heat capacity than air, meaning it takes significantly more energy to change its temperature, and it retains that heat for much longer periods (thermal inertia).
Q4. In a square of 500 km side for an easterly current, which decreases in magnitude towards north at a rate of 10 m/s per 100 km, what is the mean vertical component of the relative vorticity (s^-1)?
Vorticity = dV/dx - dU/dy. Easterly means U is negative. Decreasing magnitude northwards means dU/dy is positive. Rate = 10 / 100,000 = 10^-4. Thus, vorticity = 0 - 10^-4 = -1 x 10^-4 s^-1.
Q5. In a certain alluvial basin of 200 km^2, 180 Mm^3 of groundwater was pumped in a year and the groundwater table dropped by about 5 m during the year. Assuming no replenishment, the specific yield of the aquifer is:
Volume of aquifer drained = Area * Drop = 200,000,000 m^2 * 5 m = 1,000 Mm^3. Specific yield = Volume pumped / Volume drained = 180 / 1000 = 0.18.
Q6. If the typical radius of a cloud droplet is 100 times less than that of a raindrop, how many cloud droplets make a raindrop?
Volume of a sphere is proportional to the cube of its radius (r^3). If the radius increases by a factor of 100, the volume increases by a factor of 100^3, which equals 1,000,000.
Q7. Which one of the following is NOT linked to ozone destruction in the stratosphere?
Volatile Organic Compounds (VOCs) and hydrocarbons are primary contributors to tropospheric (ground-level) smog and ozone *creation*, not stratospheric ozone destruction.
Q8. The difference between virtual temperature and actual temperature for a moist air parcel is likely to be maximum over:
Virtual temperature is the temperature dry air would need to have the same density as moist air. The difference is greatest where moisture is highest, which is over the warm, wet equatorial oceans.
Q9. The longitudinal and compressional wave velocities in a rock are 6.0 km/s and 4.0 km/s respectively. Its Poisson's ratio is:
Using the formula v = [ (Vp/Vs)^2 - 2 ] / [ 2((Vp/Vs)^2 - 1) ]. Vp/Vs = 1.5. So v = [ 2.25 - 2 ] / [ 2(2.25 - 1) ] = 0.25 / 2.5 = 0.1.
Q10. A 2.0 km thick, and isostatically uncompensated, elevated land mass of density 2.7 g/cc is associated with a 14.0 km root at the crust-mantle boundary, where the mantle is denser by 0.3 g/cc than the lower crust. What would be the thickness of the root, when the land mass is isostatically compensated?
Using Airy's isostasy model: Root Thickness (R) = Elevation (h) * (Crust Density / Density Contrast). R = 2.0 * (2.7 / 0.3) = 2.0 * 9 = 18.0 km.