The Union Public Service Commission abbreviated as UPSC, is responsible for recruiting and conducting examinations for several Central Government A group and B group of central services. The UPSC CGS exams are conducted for hiring various A & B group officers like Geologist, Geophysicist, Chemist and Junior Hydrologist across multiple government departments of India. The aspirants need to practice the UPSC Combined Geo Scientist Important Topics to clear the Prelims and Mains exam.

UPSC Combined Geo Scientist Important Topics PDF Download

• The UPSC CGS is a three-tier examination consisting of the Prelims, Mains and Personal Interview, and by cracking all the stages, a candidate can secure a job in various government departments. 
• The UPSC CGS Prelims exam is an online multiple-choice question and answer format. The UPSC CGS Mains exam is an offline subjective test with a descriptive question and answer format. 
• Go through all the probable UPSC CGS Important Questions that you need to prepare in order to clear the exam
• The Prelims has two papers the General Studies & topics of the relevant stream like Geology/Hydrology, Geophysics and Chemistry. The Mains incorporates three papers from the relevant streams of Geology and Hydrology, Geophysics and Chemistry.
• In the Prelims stage, there is a negative marking, while in Mains stage there is no negative marking
• Aspirants preparing for UPSC CGS exams need to follow and practice the important topics to get qualified

UPSC CGS Prelims Exam Pattern 2020

The UPSC CGS Prelims examinations consist of Paper I and Paper II with a separate time duration of two hours each. The Paper I have common topics for all candidates that is General Studies. For Paper II, candidates are requested to follow their respective subjects. The total time duration allotted is 4 hours, and the total marks are 400. This is a written online examination with multiple choice question and answer format. 

Number of Papers	Number of the Subjects	Maximum Marks	Time Duration
Paper I	General Studies	200	2 Hours
Paper-II	Geology/Hydrology/Geophysics/Chemistry	200	2 Hours
Total	400	4 Hours

UPSC Combined Geo Scientist Important Topics for General Studies

The UPSC CGS Prelims Important topics for General Studies mainly focus on the General Knowledge and Current Affairs topics and are discussed in detail below. 

• General Science.
• History of India and Indian National Movement.
• Current events of national and international importance.
• Indian Polity and Governance.
• Economic and Social Development.
• General issues on Environmental Ecology, Bio-diversity, and Climate Change.
• Indian and World Geography.

 UPSC CGS Prelims Important Topics for Geology/Hydrogeology

The UPSC CGS Prelims Important topics for Geology/Hydrology includes chapters like Physical Geology, Mineralogy, Palaeontology, and others. The topics are given below in detail. 

• Physical Geology.
• Economic Geology.
• Structural Geology.
• Mineralogy.
• Paleontology.
• Igneous Petrology.
• Metamorphic Petrology.
• Sedimentology.
• Stratigraphy.
• Hydrogeology.

 UPSC CGS Prelims Important Topics for Geophysics

The UPSC CGS Prelims Important topics for Geophysics include chapters like Solid Earth Geophysics, Electromagnetism, Mathematical Approaches, and others. The topics are given below in detail. 

• Solid Earth Geophysics.
• Geophysical Prospecting.
• Electromagnetism.
• Mathematical Methods in Geophysics.
• Remote Sensing and Thermodynamics.
• Nuclear Physics and Radiometry.

UPSC CGS Prelims Important Topics for Chemistry

The UPSC CGS Prelims Important topics for Chemistry include chapters like Chemical Periodicity, Chemical Bonding and Structures, and others. The topics are given below in detail.

• Chemical periodicity.
• Acids and bases.
• Electrochemistry.
• Stereochemistry.
• Solutions of non-electrolytes.
• Basic organic chemistry.
• Chemical bonding and structure.
• Types of organic reactions.
• Molecular Rearrangements.
• Kinetic theory and the gaseous state.
• The theoretical basis of quantitative inorganic analysis.
• Chemical thermodynamics and chemical equilibrium.

UPSC CGS Mains Exam Pattern

The UPSC CGS Mains examinations consist of Paper I, Paper-II and Paper III with a separate time duration of three hours each. The Paper I and Paper II have common topics for candidates of Geology and Hydrology. For Paper III, candidates of Geology and Hydrology are requested to follow their relevant discipline. Other candidates from Geophysics and Chemistry have distinct curriculum from their subjects for all the three papers. The total time duration allotted is 9 hours, and the total marks are 600. This is a written online examination with a descriptive question and answer format. The candidates are allowed to use the non-programmable calculator in the examination. 

Number of Papers	Name of the Subject	Maximum Marks	Time Duration
Paper I	Geology/Hydrology/Geophysics/Chemistry	200	3 Hours
Paper-II	Geology/Hydrology/Geophysics/Chemistry	200	3 Hours
Paper III	Geology/Hydrology/Geophysics/Chemistry	200	3 Hours
Total	600	-

UPSC CGS Mains Important Topics for Geology and Hydrology

The UPSC CGS Mains Important Topics for Geology and Hydrology includes basic concepts from Paper I around geomorphic theories about evolution, formation, and history of the earth. Other topics incorporate sedimentology, palaeontology, etc. Paper-II encompasses vital topics like Mineralogy and Metamorphic Petrology. Precious metals and elements are important topics that candidates must focus on Paper III from Geology. If aspirants are preparing for Hydrology then for Paper III vital chapters consist of Groundwater and Hydraulics. Candidates must be well aware of concepts of Water Table, Water Wells, Conservation and Purification Techniques to score well in this paper. 

Geology/Hydrology Paper I

• Stratigraphy.
• Paleontology.
• Sedimentology.
• Structural geology.
• Physical geology and remote sensing.

Geology/Hydrology Paper II

• Mineralogy.
• Igneous petrology.
• Metamorphic petrology.
• Geodynamics.
• Geochemistry and isotope geology.

Geology Paper III

• Economic geology.
• Mineral exploration.
• Fuel geology and Engineering geology.
• Environmental geology and Natural hazards.
• Indian mineral deposits and mineral economics.

Hydrology Paper III

• Groundwater exploration.
• Water wells and groundwater levels.
• Groundwater quality and management.
• Occurrence and distribution of groundwater.
• Groundwater movement and well hydraulics.

UPSC Combined Geo Scientist Important Topics for Geophysics

The UPSC CGS Mains Important Topics for Geophysics revolves around the physics related to the earth. The vital topics from Paper I include seismology and earth geophysics with mathematical calculations and different laws in physics. Paper-II includes important chapters like Magnetic Fields, Collisions, Nuclear Particles, etc. The final paper (Paper III) covers topics of ocean and radar systems. 

Geophysics Paper I (Part-A)

• Solid Earth Geophysics.
• Earthquake Seismology.
• Geophysical Inversion.
• Mathematical methods in Geophysics.

Geophysics Paper I (Part-B)

• Electrodynamics.
• Electromagnetic Theory.
• Mathematical Methods of Physics.
• Introductory Atmospheric and Space Physics.

Geophysics Paper-II (Part-A)

• Potential Field (Gravity and Magnetic) Methods.
• Electrical and Electromagnetic methods.
• Seismic Prospecting.
• Borehole Geophysics.

Geophysics Paper-II (Part-B)

• Classical Mechanics.
• Nuclear and Particle Physics.
• Thermodynamics and Statistical Physics.
• Atomic and Molecular Physics and Characterization of materials.

Geophysics Paper III (Part-A)

• Marine Geophysics.
• Radiometric and Airborne Geophysics.
• Geophysical Signal Processing.
• Remote Sensing and Geohydrology.

Geophysics Paper III (Part-B)

• Laser systems.
• Quantum Mechanics.
• Solid State Physics and Basic Electronics.
• Digital electronics, Radar systems, Satellite communications.

UPSC Combined Geo Scientist Important Topics for Chemistry

The UPSC CGS Mains Important Topics for Chemistry has three papers. In Paper I candidates must remember the periodic table by heart followed by other topics like Redox Titrations, Metal Clusters, Nuclear Models that carry significant marks. Paper-II Physical Chemistry is a more theory-oriented paper and deals with vital topics like Gas Laws, Catalysis Concepts and Electrochemistry. For Paper III candidates should focus on Reactions, Structural bonds, and Spectroscopy. 

Chemistry Paper I (Inorganic Chemistry)

• Inorganic solids.
• Acid-base titrations.
• Gravimetric Analysis.
• Nuclear chemistry.
• Redox Titrations.
• Complexometric titrations.
• Organometallic compounds.
• Chemistry of coordination compounds.
• Chemistry of d- and f-block elements.

Chemistry Paper II (Physical Chemistry)

• Solids.
• Electrochemistry.
• Quantum chemistry.
• Kinetic theory and the gaseous state.
• Chemical thermodynamics and chemical equilibrium.
• Chemical kinetics and catalysis.
• Basic principles and applications of spectroscopy.
• Photochemistry.

Chemistry Paper III (Part-A) (Analytical Chemistry)

• Errors in quantitative analysis.
• Spectroscopic methods of analysis.
• Thermal methods of analysis.
• Separation Methods.
• X-ray methods of Analysis.
• Inductively coupled plasma spectroscopy.
• Analysis of geological materials.

Chemistry Paper III (Part- B) (Organic chemistry)

• Addition reactions.
• Electrocyclic Reactions.
• Oxidation and Reduction.
• Reactions at the carbonyl group.
• Unstable, uncharged intermediates.
• Spectroscopic methods of analysis.

UPSC CGS Cut-Off Marks

• The UPSC CGS total cut-offs are established in all three stages of the examination the Prelims, Mains and Personal Interviews. 
• The Cut-Offs for the written examination are calculated on total marks of 700.
• The Cut-Offs for the final stage, including personal interviews, are calculated on total marks of 900.
• The cut-off patterns depend upon the level of difficulty, marking scheme and previous year’s cut-offs.
• The cut-offs are also influenced by the number of candidates appearing in the examination and the number of seats available. 
• 1/ 3 rd marks are deducted for each incorrect answer in the UPSC CGS Prelims.
• There is no marks deduction for a wrong answer in the UPSC CGS Mains. 
• The cut-offs marks are higher for general category candidates than reserved category candidates. 

The candidates preparing for the UPSC CGS should have a Master’s Degree in Geology, Physics, and Chemistry. Qualifying all the three stages, including Personal Interview, is essential to get a scientific job in Government Departments. If a candidate fails in any paper, then they are disqualified. Thus, aspirants should follow all the Important Topics provided subject-wise for the UPSC CGS exams.