India · National Testing Agency for CSIR · phd · unverified source
Computer-based, 3 hours, Parts A (general aptitude), B and C (subject), with negative marking.
Route to a CSIR JRF for PhD work in climate and atmospheric science. Life Sciences (ecology units) is the other CSIR NET paper used by ecologists. Built from general knowledge.
Official source: https://csirnet.nta.ac.in/
Original questions written to this exam's published syllabus and pattern. Not past papers.
1. A reaction has an equilibrium constant K = 1000 at 25 °C. Using ΔG° = −RT ln K (R = 8.314 J mol⁻¹ K⁻¹), what is ΔG°?
B. -17.1 kJ/mol
ΔG° = −8.314 × 298.15 × ln 1000 = -17.1 kJ/mol. +17.1 has the wrong sign; −7.4 uses log₁₀ instead of ln; −17123 forgets to convert J to kJ.
Environmental Chemistry · Chemical equilibrium, thermodynamics and reaction kinetics
2. The oldest known terrestrial minerals, about 4.4 billion years old, are zircons from:
C. Jack Hills, Western Australia
They suggest early crust and perhaps water. The Deccan Traps, Grand Canyon rocks and Everest summit rocks are far younger.
Earth Systems & Environmental Geoscience · Origin and evolution of the earth and its spheres
3. What is the average environmental lapse rate in the troposphere?
C. About 6.5 °C per km
The standard atmosphere uses 6.5 °C per km. 9.8 °C per km is the dry adiabatic lapse rate of a rising unsaturated parcel, not the average environmental profile.
Atmospheric Science & Agrometeorology · Layers of the atmosphere and their characteristics
4. Match the Milankovitch cycle with its approximate dominant period: obliquity (axial tilt) varies with a period of
C. 41,000 years
Obliquity, the tilt between about 22.1° and 24.5°, cycles with a period of about 41,000 years. Precession has periods of about 19,000–23,000 years; eccentricity has periods near 100,000 and 400,000 years.
Climate System Science · The climate system and its components
5. In a zero-dimensional energy-balance model, C dT/dt = F − λT. Take a 100 m ocean mixed layer (density 1025 kg m⁻³, specific heat 3990 J kg⁻¹ K⁻¹) and λ = 1.2 W m⁻² K⁻¹. What is the response time τ = C/λ in years (1 year = 3.156 × 10⁷ s)?
C. 10.8 years
C = 1025 × 3990 × 100 = 4.090e+08 J m⁻² K⁻¹; τ = C/λ = 3.408e+08 s ÷ 3.156 × 10⁷ = 10.8 years. 5.4 years uses a 50 m layer; 3945 converts seconds to days, not years; 15.6 multiplies by λ instead of dividing.
Climate Models, Scenarios & Downscaling · Model hierarchy: energy-balance, GCM, ESM and regional models
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