Complete Guide to CDS science questions previous year trends 2027

Analyzing CDS science questions previous year trends reveals that Physics, Chemistry, and Biology contribute a steady 30 questions carrying 30 marks in the General Knowledge paper. Physics dominates with conceptual numericals, Biology focuses on human physiology, and Chemistry tests applied concepts, making a structured PYQ analysis essential for clearing the UPSC cutoff.

What is the Exam?

The Combined Defence Services (CDS) Examination is conducted biannually by the Union Public Service Commission (UPSC) for recruitment to the Indian Military Academy (IMA), Indian Naval Academy (INA), Air Force Academy (AFA), and Officers Training Academy (OTA). As expert exam strategists at Exam Bhai, we recognize that clearing the CDS written examination requires a meticulous understanding of not just the core subjects, but the shifting trends of questions asked by the commission.

Science is a scoring pillar in the General Knowledge paper for IMA, INA, and AFA aspirants. Over the last several recruitment cycles, the nature of science questions has evolved from rote memorization of factual data to applied, statement-based questions that test conceptual clarity. Understanding how these trends have shifted enables candidates to tailor their preparation efficiently, ensuring high accuracy and better time management during the exam.

Key Highlights 2026

To keep our aspirants ahead of the curve, here are the vital parameters governing the examination framework:

• Conducting Body: Union Public Service Commission (UPSC)
• Frequency: Conducted twice a year (CDS I and CDS II)
• Stages of Selection: Written Examination followed by the Services Selection Board (SSB) Interview
• Paper for Science: General Knowledge (Paper II for IMA, INA, AFA)
• Total Science Questions: Generally 30 questions out of 120 in the GK paper
• Marking Scheme: 1/3rd negative marking for incorrect answers
• Medium of Exam: Bilingual (English and Hindi)

Syllabus 2026

The UPSC does not prescribe a rigidly narrow syllabus for the General Knowledge paper, but analyzing past trends allows us at Exam Bhai to categorize the science curriculum into three distinct segments. Here is the detailed breakdown:

Exam Pattern

The CDS written examination pattern differs slightly depending on whether you are opting for the Naval, Military, Air Force academies or the Officers Training Academy. Below is the structural layout for IMA, INA, and AFA candidates:

For OTA candidates, Mathematics is excluded, making the maximum marks 200 across 4 hours. Within the 100-mark General Knowledge paper, science holds a 30-mark weightage. To test your grasp on these topics under actual exam conditions, you can practice free mock tests for CDS 2027 on Exam Bhai to analyze your speed and accuracy.

Eligibility Criteria

Before diving deep into preparation, candidates must ensure they meet the strict eligibility parameters set by the commission. According to official data hosted on upsc.gov.in, the criteria include:

• Nationality: Must be an Indian citizen, a subject of Bhutan, Nepal, or a Tibetan refugee who came over to India before January 1, 1962.
• Educational Qualification:
  • For IMA and OTA: Graduation degree from a recognized university.
  • For INA: Degree in Engineering from a recognized university/institution.
  • For AFA: Graduation with Physics and Mathematics at 10+2 level or a Bachelor of Engineering degree.
• Age Limit: Varies by academy, typically ranging between 20 to 24 years at the time of commencement of the course.
• Marital Status: Unmarried candidates only for certain academies.

Application Process

The application process for CDS is completely online through the official UPSC portal. As part of our guidance at Exam Bhai, we recommend following these core steps:

1. One-Time Registration (OTR): Register your profile on the official UPSC OTR portal.
2. Form Filling: Log in using your credentials, select the CDS examination notification, and fill out personal and educational details.
3. Preference Selection: Provide your order of preference for IMA, INA, AFA, and OTA.
4. Fee Payment: Pay the requisite application fee (exempted for female candidates and SC/ST categories).
5. Center Selection and Final Submission: Choose your examination center carefully and submit the application, downloading a copy for future reference.

Preparation Strategy

Mastering science questions requires a mix of conceptual clarity and regular testing. Based on previous year trends, UPSC frequently frames questions testing applied daily life science rather than pure rote definitions. Here is our strategic roadmap at Exam Bhai:

• NCERT Foundation: Read NCERT textbooks from Class 6 to Class 10 thoroughly. These form the undisputed backbone of UPSC science questions.
• Topic-Wise PYQ Analysis: Dissect the last 5 years of question papers. Note how Biology questions pivot heavily toward human systems and diseases, while Physics favors conceptual numericals on optics and electricity.
• Active Revision: Maintain short, crisp notes for chemical formulas, scientific units, and biological terms.
• Simulated Practice: Build exam temperament by timing your section attempts. You can practice previous year trends sectional quizzes for CDS 2027 on Exam Bhai to isolate weak spots.
• Regular Assessments: Benchmark your progress continuously. We strongly advise candidates to access full-length structured practice sets for CDS 2027 on Exam Bhai to replicate the real exam environment.

Cut-Off Trends

Analyzing historical cut-off trends provides critical perspective on target scores. According to official historical reports and notifications published on upsc.gov.in, the sectional cut-off for the General Knowledge paper consistently hovers around 20% (i.e., 20 marks out of 100), provided candidates clear the overall aggregate cut-off for their respective academy.

• IMA Cut-Off Range (Historical Average): 130 - 145 marks out of 340
• INA Cut-Off Range (Historical Average): 120 - 135 marks out of 340
• AFA Cut-Off Range (Historical Average): 140 - 155 marks out of 340
• OTA Cut-Off Range (Historical Average): 95 - 110 marks out of 200

Because the GK paper often acts as a bottleneck for engineering and non-engineering aspirants alike, securing 18 to 22 marks out of the 30 science questions can comfortably safeguard your sectional clearance and boost your total aggregate score.

Frequently Asked Questions

Q1: How many science questions are usually asked in the CDS General Knowledge paper?
A: Typically, UPSC asks around 30 questions from General Science out of the total 120 questions in the GK paper, distributed fairly evenly across Physics, Chemistry, and Biology.

Q2: Are NCERT books enough to clear the science portion in CDS 2027?
A: Yes, NCERT textbooks from Class 6 to Class 10 provide an exceptionally strong foundation. However, candidates must supplement them by practicing previous year questions to understand the applied, statement-based framing style of UPSC.

Q3: Is there any negative marking for science questions in CDS?
A: Yes, there is a penalty of 1/3rd (0.33) of the total marks assigned to that question for every incorrect answer marked in the objective paper.

Q4: Which branch of science carries the maximum weightage in CDS exams?
A: Historically, Biology and Physics tend to share the highest weightage, often accounting for 11 to 12 questions each, while Chemistry comprises the remaining 6 to 8 questions.

Q5: Can arts or commerce graduates attempt CDS science questions successfully?
A: Absolutely. Since the science syllabus is restricted up to the Class 10 level, non-science background students can easily master the core concepts with dedicated NCERT reading and consistent question practice.

Q6: Where can I find reliable solved previous year papers for CDS science?
A: You can explore comprehensive, curated question banks and mock environments directly through dedicated platforms like Exam Bhai to practice historical trends effectively.