How is JEE Main syllabus different from JEE Advanced Syllabus? This question bothers every engineering aspirant who has to clear the hurdle of JEE Main and JEE Advanced for admissions to 23 IITs. Every year around 12 lakh aspirants appear for JEE Main, the first step to IIT admission and of the total test takers only 20% are able to qualify for JEE Advanced. This makes the IIT admission process more stringent as students brace themselves for All India Ranks.
Students whose only aim is to get admission in Indian Institutes of Technology (IITs) will have to crack JEE Advanced, so they need to prepare accordingly. Here we discuss the major difference between JEE Main and JEE Advanced which will be helpful in preparation–
Physics  Difference between JEE Main and JEE Advanced Syllabus
Topics included in physics section of JEE Main but not in JEE Advanced 
Topics included in Physics section of JEE Advanced but not in JEE Main

Electronic Devices: Semiconductors; semiconductor diode: IV characteristics in forward and reverse bias; diodes as a rectifier; IV characteristics of LED, photodiode, solar cell and diode; Zener diode as a voltage regulator. Junction transistor, transistor action, characteristics of a transistor, transistor as an amplifier (common emitter configuration) and Oscillator; Logic gates (OR, AND, NOT, NAND and NOR). Transistor as a switch Electromagnetic Waves: Electromagnetic waves; Characteristics of Electromagnetic Waves; Transverse nature of electromagnetic waves; Electromagnetic spectrum; Applications of Electromagnetic waves Communication Systems: Electromagnetic waves’ propagation; Amplitude and Frequency Modulation; Bandwidth of signals & transmission medium; Basic elements of a Communication System (Block Diagram only). 
Thermal Physics: Newton’s law of cooling; Blackbody radiation; Absorptive and Emissive powers; Kirchhoff’s law; Wien’s Displacement Law; Stefan’s Law.

Download complete syllabus and study Material for IIT JEE Main  here
Chemistry  Difference between JEE Main and JEE Advanced Syllabus
Topics included in Chemistry section of JEE Main but not in JEE Advanced 
Topics included in Chemistry section of JEE Advanced but not in JEE Main

Biomolecules: Vitamins Classification and functions; Nucleic acids – Chemical constitution of DNA and RNA Chemistry in Everyday Life Chemicals in medicines – Analgesics, tranquilizers, antiseptics, disinfectants, antimicrobials, antifertility drugs, antibiotics, antacids, antihistamines – their meaning and common examples. Chemicals in food Preservatives, artificial sweetening agents – common examples Cleansing agents Soaps and detergents, cleansing action

Electrochemistry: Equivalent Conductivity Nuclear Chemistry: Radioactivity; Properties of alpha, beta and gamma rays; Kinetics of radioactive decay (decay series excluded), carbon dating; Stability of nuclei with respect to protonneutron ratio; Brief discussion on fission and fusion reactions.

Download complete syllabus and study Material for IIT JEE Advanced  here
Mathematics  Difference between JEE Main and JEE Advanced Syllabus
Topics included in Mathematics section of JEE Main but not in JEE Advanced –
 Sets, Relations and Functions: Sets and their representation; Union, intersection and complement of sets and their algebraic properties; power set; relation, Types of relations, equivalence relations
 Statistics and Probability: Measures of Dispersion; calculation of mean, median. Mode of grouped and ungrouped data calculation of standard deviation, variance and mean deviation for grouped and ungrouped data
 Trigonometry: Heights and Distances
 Mathematical Reasoning: Statements, logical operations and, or, implies, implied by, if and only if, Understanding of tautology, contradiction, converse and contra positive
Important Topics in Mathematics for JEE Main 2018
Conclusion –
In order to crack JEE Advanced for admissions to IIT, students need to have thorough knowledge of the JEE Advanced syllabus. Where JEE Main question paper is based on class 11 and class 12 CBSE syllabus and students have option to appear for Paper 1 only. The JEE Advanced test takers have to study some extra topics as mentioned in the prescribed CBSE Syllabus and also, students cannot skip either of the JEE Advanced paper i.e. Paper 1 and Paper 2.
JEE Main qualified candidates get at least 45 days to prepare for JEE Advanced, so they are advised to go through the prescribed syllabus and prepare thoroughly. With consistent efforts, students will be able to make it to IITs as they get 3 chances for JEE Main and 2 chances for JEE Advanced.
JEE Main 2018: Role and Importance of mock test before the exam