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## Important Physics Topics For JEE Mains

Subhas, a tutor from NIT Durgapur who cleared JEE Mains in 2014 tells you which physics topics are important for JEE Mains.

If you are looking to understand how to prioritize your physics study for JEE, you can use the topics listed here for reference.

(You can chat with tutors like Subhas directly on the HashLearn app. Download it here)

1) Kinematics in One Dimension: Problems involving two trains starting at certain points (same or different) with different velocities and whether they will catch up with each other or not, Motion of Balls vertically up and down (with and without initial velocities), etc.

2) Kinematics in Two Dimensions: Projectile Motion – Equation of trajectory of projectile, Radius of Curvature at the highest point, Motion of Projectile along an Inclined Plane, Effect of External Acceleration provided to Projectile in addition to Acceleration due to gravity.

3) Relative Motion: Trains travelling in same or opposite directions and time required to cross each other; Motion of a Boat along a stream and path followed for least time; Rain-fall at an angle and its relative direction with respect to the person moving along, a> straight path, b> inclined plane.

4) Newton’s Laws of Motion: Differential Equation governing motion of body, Identifying the nature of differential equation (linear or non-linear), Pulley-Block problems, Constraint Relations for multiple pulleys connected simultaneously.

5) Motion of Rigid Bodies: Finding the centre of mass of body, Position of a boat before and after – a> A man stands on a boat towed close to the harbor, b> the man jumps off the boat.

6) Rotational Motion (Very Important): Finding the Mass Inertia of a body (remember that there is an equivalent Area Moment of Inertia, but it’s not required for JEE), Shifting of the Centre of Mass when certain mass is added to or removed from the body and the new Moment of Inertia, Parallel and Perpendicular Axes Theorem (with derivations) and remembering Standard Moments of Inertia about various axes (axis passing through the centre of mass, passing through an edge about X,Y or Z axis, axis making an angle ‘?’ with the X, Y or Z axis specially for a laminar plate).

7) Rolling of Ball on a plane, Concepts of Forward and Backward Slip, Motion of Ball along an Inclined Plane in presence of Friction and Rolling, Comparison of bodies of different geometries rolling along inclined planes, Concept of INSTANTENEOUS CENTRE OF ROTATION for finding linear velocity on any point of a sphere rolling on a floor, Ladder sliding along two perpendicular walls, Equation of the trajectory of centroid of the sliding ladder.

Condition for Toppling of a body, Minimum height of an obstruction required to topple the body.

Motion of blocks on different sides of pulleys with friction.

8) Gravitation: Newton’s Law of Gravitation, Changes in nature of the force if it were a n-th power law instead of second-power law, Concept of acceleration due to gravity and its changes with height and depth from the surface of earth (Remember exact formulae for the change in value of ‘g’ when going above the surface of earth – Do not expand by Binomial Theorem initially, if h/R comes out to be of the order of 10^(-3), only then expand using Binomial Theorem), Gravitational Potential and Field densities for various bodies, Knowledge of Elementary Relativistic Theory (just formulae for Relativistic Mass Increase and Time Dilation).

9) Simple Harmonic Motion: Basic Equation for SHM, Why are Sine and Cosine functions only applicable for describing SHM equations (not tan, cot, etc.), Spring-Mass Systems (free oscillations, damped oscillations and forced oscillations), SHM of a mass or an Electric Charge around a Ring, SHM of a liquid in an U-Tube (Vertical or Inclined), SHM of a ball rolling on a hemisphere, SHM of a beam with springs fitted at different positions.

10) Waves and Oscillations: Basic Equation of Wave Motion in analytic and differential forms, Motion along a String, Concept of Nodes and Antinodes, Concept of Fundamental Frequency and Higher Order Harmonics, Wave Propagation along a String fixed at both ends and finding the wavelength or frequency, Wave Propagation along an Organ Pipe (closed at one end or open at both ends) and finding the wavelength or frequency of wave.

11) Variation in Speed of Sound with temperature and Medium Conditions, Concepts of Mach Number.

Doppler Effect – Motion of a Sound-Emitting Source in a straight line with finite velocity, and frequency of reflected sound wave a> when the body moves in same or opposite directions as the source, b> the medium(like wind) is stationary or moves with certain velocity.

12) Thermodynamics: Definition of System, Difference between Open, Closed and Isolated Systems, Why is a System needed at all, Alternative Concept of Control Volume (generally not asked in JEE, but you should know these concepts. The problems involving Variable Mass like Sand falling on a Conveyor Belt and Rocket launched into space where the mass is a function of time can be easily solved using the concepts of Control Volume), Internal Energy and the factors on which it depends , Enthalpy and its governing factors, Situations where Enthalpy change needs to be taken into account and where Internal Energy change needs to be, Knowledge of various Thermodynamic Processes (Isothermal, Adiabatic, Isobaric, Isochoric and Polytropic), Work done in each standard thermodynamic process, Representation of cycles on a graph, Slope of each curve (analytic formulae and representation on graphs), Impact of higher slope of Adiabatic Curve than Isothermal Curve, Carnot Cycle and the concept of Maximum Possible Heat Transfer, Concept of Entropy and its importance in Second Law of Thermodynamics, Clausius Inequality, Work done is maximum in reversible path explanation using concepts of entropy, Enthalpy change in chemical reactions, Gibbs’-Helmholtz Relationship, Joule-Thompson Effect, Significance of isenthalpic lines on p-T graph for ideal gases and real gases, Third Law of Thermodynamics and impossibility to verify Third Law, Work done in Polytropic Process, Concepts of Specific Heat Capacities at Constant Volume and Constant Pressure, Finding equivalent Mass and Specific Heat Capacity of a gas mixture which is constituted of n-components (with the number of moles and their individual Specific Heat Capacities as given data).

13) Kinetic Theory of Gases: Average Energy of Gases at particular temperature at particular volume (With derivations), Assumptions of Kinetic Theory, Concepts of Average Velocity, Root Mean Square Velocity, etc. along with their inter-relationships, Effect of temperature on acoustic velocity in a given medium, Ideal Gas Equation, Derivation of Universal Gas Constant and its variation with respect to a medium, Boltzmann’s Constant and its importance, Concept of Real Gases, Equation for Real Gases, Virial Equations, Graphs of real gases – particularly Nitrogen, Oxygen and Carbon dioxide and their deviation from ideal behavior , Concepts of Critical Temperature, Critical Pressure and Critical Volume, Dependence of Critical Parameters on the Real Gas Constants – ‘a’ and ‘b’.