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    Toughest Subject in IAT 2026 Paper: Physics, Chemistry or Biology? Expert Analysis

    Toughest Subject in IAT 2026 Paper: Physics, Chemistry or Biology? Expert Analysis

    Shivani PooniaUpdated on 08 Jun 2026, 12:15 PM IST

    The IISER Aptitude Test (IAT) is one of the most competitive science entrance exams in India. It tests candidates on four subjects: Physics, Chemistry, Mathematics and Biology. While all four carry equal weightage of 15 questions each (60 marks per subject, 240 total), they are far from equal in difficulty - on the basis of a student's perspective. Year after year, students walking out of IAT exam centres share one consistent observation: not all subjects feel the same.

    This Story also Contains

    1. IAT 2026 Toughest Subject
    2. IAT 2026 Subject-wise Difficulty Analysis
    3. Detailed Analysis of IISER Aptitude Test 2026
    4. Subject-wise Difficulty Ranking in IAT
    5. Previous Year IAT Subject-wise Difficulty Trend (2022–2025)
    6. IISER 2026 Result
    7. IISER 2026 Answer Key
    8. IISER 2026 Rank Vs Marks (Tentative)
    Toughest Subject in IAT 2026 Paper: Physics, Chemistry or Biology? Expert Analysis
    Toughest Subject in IAT 2026 Paper

    This article breaks down the difficulty level of each subject in the IAT 2026. It is based on student reactions, past paper trends and subject wise analysis. We have also given you previous years difficulty analysis from 2022 to 2025 to help you understand which section is the toughest and how to prepare for it.

    IAT 2026 Toughest Subject

    Physics was the toughest section in the IAT 2026 Paper because it was lengthy, time-consuming, and concept-based. Questions were based on multiple concepts, and solving a single numerical problem required various concepts and formulas. Questions came from topics like Mechanics, Modern Physics, Current Electricity, Electrostatics, and Thermodynamics.

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    IAT 2026 Subject-wise Difficulty Analysis

    The IAT 2026 exam was conducted on June 7, 2026. The subject-wise difficulty level along with IAT toughest subject for this year is updated below.

    Section

    Difficulty Level

    Analysis

    Overall

    Moderate to Difficult

    The overall paper difficulty level of the exam was Moderate to Difficult.

    Physics

    Difficult

    Physics was Moderate to Difficult. Physics was time-consuming and concept-based.

    Chemistry

    Moderate

    Chemistry was Moderate and Scoring. A mix of direct theoretical questions and application-based questions was asked.

    Mathematics

    Moderate to Difficult

    Mathematics was Difficult and Lengthy. Questions were lengthy and consisted of multiple calculation steps.

    Biology

    Easy to Moderate

    Biology was Easy to Moderate. Questions were direct and concept-based

    Detailed Analysis of IISER Aptitude Test 2026

    Overall Analysis

    • The overall paper difficulty level of the exam was Moderate to Difficult.

    • Biology and Chemistry were easy and based on fundamental concepts.

    • Mathematics and Physics were calculation-based and involved multiple concepts.

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    Download EBook

    Subject-Wise Analysis

    Biology

    • Biology was Easy to Moderate

    • Questions were direct and concept-based

    • Questions were aligned with NCERT.

    • Topics like Genetics, Human Physiology, Ecology, and Biotechnology were asked.

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    Chemistry

    • Chemistry was Moderate and Scoring

    • A mix of direct theoretical questions and application-based questions was asked.

    • Physical Chemistry was calculation-based, while Organic and Inorganic focused heavily on fundamental understanding.

    • Questions were asked from topics like Organic Reaction Mechanisms, Chemical Bonding, Coordination Compounds, and Electrochemistry.

    Physics

    • Physics was Moderate to Difficult

    • Physics was time-consuming and concept-based.

    • Questions were based on multiple concepts, and to solve a single numerical problem, various concepts and formulas were required.

    • Questions came from topics like Mechanics, Modern Physics, Current Electricity, Electrostatics, and Thermodynamics.

    Mathematics

    • Mathematics was Difficult and Lengthy

    • Questions were lengthy and consisted of multiple calculation steps.

    • Advanced application-based questions were also asked.

    • Questions were asked from topics like Calculus, Probability, Matrices & Determinants, and Coordinate Geometry.

    Subject-wise Difficulty Ranking in IAT

    Based on student reactions and IAT 2026 paper analysis here is how the four subjects rank in terms of difficulty:

    Rank

    Subject

    Difficulty Level

    Why

    1

    Physics

    Hard

    Application-based, multi-concept questions, unpredictable chapter coverage

    2

    Mathematics

    Moderate to Hard

    Calculus-heavy, requires problem-solving depth; varies year to year

    3

    Chemistry

    Moderate

    Mostly NCERT-based; Inorganic can be tricky

    4

    Biology

    Easy to Moderate

    Most scoring; largely NCERT-based, factual questions

    Previous Year IAT Subject-wise Difficulty Trend (2022–2025)

    You can check the IISER Previous Year Question Paper to analyze the difficulty level trends. A summary of the above has been given for you in this table:

    Year

    Physics

    Chemistry

    Mathematics

    Biology

    Overall IAT Difficulty

    2025

    Hard

    Moderate

    Moderate–Hard

    Moderate

    Moderate

    2024

    Moderate–Hard

    Easy–Moderate

    Moderate

    Moderate

    Moderate

    2023

    Moderate

    Moderate

    Moderate

    Easy–Moderate

    Moderate

    2022

    Moderate–Hard

    Moderate

    Moderate–Hard

    Easy

    Moderate–Hard

    IISER 2026 Result

    The IISER 2026 results will be announced by the Indian Institute of Science Education and Research on its official website. Students will be able to download their results using their application number and date of birth a few days after the exam gets over.

    IISER 2026 Answer Key

    The IISER 2026 official answer key has been released on the official website. You can use this to estimate your marks and results. After calculating your estimated result, you can also check the below information for getting an idea of tentative ranking.

    IISER 2026 Rank Vs Marks (Tentative)

    IISER 2026 rank vs marks details are given below. Please note that the below details are estimates and subjective to change.

    Marks (Out of 240)

    Expected Rank Range

    200+

    1 - 80

    180 - 199

    81 - 250

    160 - 179

    251 - 800

    140 - 159

    801 - 2,000

    120 - 139

    2,001 - 4,000

    100 - 119

    4,001 - 7,000

    80 - 99

    7,001 - 12,000

    60 - 79

    12,001 - 20,000

    Below 60

    20,000+

    Frequently Asked Questions (FAQs)

    Q: Which is the toughest subject in the IAT exam?
    A:

    Physics is consistently rated as the toughest subject in the IAT.

    Q: Is Biology easy in the IISER Aptitude Test?
    A:

    Yes, Biology is generally considered the easiest and most scoring section in IAT.

    Q: What is the overall difficulty level of IAT 2026?
    A:

    The overall difficulty level of the IAT 2026 was moderate to difficult.

    Q: Is IAT harder than JEE Mains?
    A:

    The IAT is not directly comparable to JEE Mains since it also tests biology. But overall JEE level is harder than IAT.

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    Questions related to IISER Aptitude Test

    On Question asked by student community

    Have a question related to IISER Aptitude Test ?

    Hi! To prepare for the IISER Aptitude Test, you need to understand the syllabus, exam pattern, and follow a proper preparation strategy. Click on the links below to learn more.

    Link: IISER Syllabus and Pattern
    IISER Preparation Tips

    You can find IISER Aptitude Test (IAT) previous year question papers and answer keys on educational websites like Careers 360. They provide with the official question papers as well as the answer key.

    Read more at

    https://engineering.careers360.com/articles/iiser-2025-question-paper-solutions

    Hello,

    If you have uploaded the old EWS certificate (2024–2025) instead of the new one (2025–2026), there is a chance that it may not be accepted, as the IISER notification clearly asks for the valid and updated EWS certificate for the year 2025–2026.

    Right now, if the correction window is

    Hello,

    If you have selected OBC-NCL category and uploaded a Central OBC-NCL certificate , then there is no issue .

    IISER accepts Central OBC-NCL certificate , as long as it is valid and issued by a competent authority. Just make sure the certificate is:

    • Issued within one year from the

    Hello aspirant,

    Applicants must take either the JEE Main or JEE Advanced exam in order to be considered for admission to the best engineering institutes in India. JEE Advanced and Main are administered by separate bodies. Because the JEE Advanced exam is more difficult than the JEE Main exam, candidates