Below is the syllabus of KVPY you can check
Physics- Units and Measurements, Vectors, and Calculus in Physics,Motion in a Straight line,Motion in a Plane,Laws of Motion,Work, Energy and Power,System of particles and Rotational Motion,Gravitation,Mechanical Properties of solids,Mechanical Properties of fluids,Thermal Properties of Matter,Thermodynamics,Kinetic Theory,Oscillations,Waves,Electric Charges and fields,Electrostatic Potential and Capacitance,Current Electricity,Moving charges and Magnetism,Magnetism and Matter,Electromagnetic Induction,Alternating Current,Electromagnetic Waves,Ray Optics and Optical Instruments,Wave Optics,Dual Nature Of Radiation and Matter,Modern Physics (Atoms, Nuclei),Semiconductor Devices
Chemistry- Some Basic Concepts of Chemistry,Structure of Atom,Classification of Elements and Periodicity in Properties,Chemical Bonding and Molecular Structures,States of Matter,Thermodynamics,Equilibrium: Chemical and Ionic,Redox Reaction,Hydrogen,The s-Block elements,The p-Block elements Group 13 & 14,Organic Chemistry, some Basic Principle and Techniques,Hydrocarbons,Solid State,Solution,Chemical Kinetics,Surface Chemistry,General Principles and isolation of elements,p - Block elements,d and f Block elements,Coordination Compounds,Halo-alkanes and Halo-arenes,Alcohols, Phenols and Ethers,Aldehydes, Ketones and Carboxylic acids,Amines,Biomolecules and Polymer
Mathematics- Sets, Relations and Functions & Logarithm,Trigonometry Phase 1,Trigonometry Phase 2,Inverse Trigonometric functions,Principle of Mathematical induction,Linear Inequalities,Linear Programming,Quadratic Equation,Sequence and Series,Binomial Theorem,Straight lines,Circles,Conic Sections,Complex Numbers,Permutations and Combinations,Probability,Statistics and Mathematical reasoning,Limits and ContinuityDifferentiability and differentiation,Applications of Derivatives,Indefinite Integration,Definite Integration,Matrices and Determinants,2-d and 3-d Geometry,Vector Algebra

There is no specific syllabus for KVPY exam as your 10th,11th, and 12th topics of NCERT are the only ways possible to crack it with flying colours. So it is advisable to complete your NCERT properly and for add on you can start giving online mock papers as this will be helpful for you to know the exam pattern and will also teach you how to manage time during exam moreover by doing this you will also get to know what all weak areas you still have where you need more practice.

Hope this helps!!!