Class 11 Physics Notes: Chapter-wise Formulas and Marks Guide

These class 11 physics notes give a quick, chapter-wise revision of the NCERT book. Class 11 builds the base for Class 12 physics, and it is also the base for NEET and JEE. The theory paper carries 70 marks, and practicals carry 30 marks. First, check the marks by unit. Then revise the formulas chapter by chapter, because most numericals come from a small set of them.

Class 11 Physics Notes: Marks Distribution

The paper groups the units into four blocks. This table helps you plan your time.

Units	Topics	Marks
I–III	Measurement, kinematics, laws of motion	23
IV–VI	Work and energy, rotation, gravitation	17
VII–IX	Bulk matter, thermodynamics, kinetic theory	20
X	Oscillations and waves	10

Please check the latest CBSE syllabus before you finalise your plan, because the board can revise the weightage. The Physical World chapter is short and is not evaluated, so spend your time on the other chapters.

Chapter 1: Units and Measurements

Measurement compares a quantity with a standard unit. For this, the SI system has seven base units, such as the metre, kilogram and second. Dimensions show how a quantity depends on mass, length and time, so they help you check formulas. For instance, the dimension of force is [M L T⁻²]. Significant figures show the precision of a measurement, and errors can be absolute, relative or percentage. For a product or quotient, the relative errors add up.

Chapter 2: Motion in a Straight Line

Motion in one dimension uses displacement, velocity and acceleration. For uniform acceleration, the three equations are v = u + at, s = ut + ½at² and v² = u² + 2as. Also, the slope of a position-time graph gives velocity, and the slope of a velocity-time graph gives acceleration. Because the area under a velocity-time graph gives displacement, you can solve many problems without any algebra.

Chapter 3: Motion in a Plane

Vectors have magnitude and direction. Therefore, you add them by the triangle or parallelogram law, and you can resolve them into components. In projectile motion, the horizontal velocity stays constant, while gravity acts on the vertical part. The time of flight is T = 2u sinθ / g, the range is R = u² sin2θ / g, and the maximum height is H = u² sin²θ / 2g. Finally, in uniform circular motion, the centripetal acceleration is v²/r.

Chapter 4: Laws of Motion

First, Newton’s first law defines inertia. Next, the second law gives F = ma, and then the third law says that every action has an equal and opposite reaction. Momentum is p = mv, and the force equals the rate of change of momentum. Friction opposes motion, so the limiting friction is f = μN. On a banked road or a circle, a free-body diagram shows every force clearly. Therefore, always draw one before you write equations.

Chapter 5: Work, Energy and Power

First, work is W = F d cosθ. Next, the work-energy theorem says that net work equals the change in kinetic energy, where K = ½mv². Likewise, potential energy near the ground is U = mgh, and a spring stores ½kx². When only conservative forces act, the total mechanical energy stays constant. Moreover, power is work divided by time, and P = F v. In collisions, momentum is always conserved, but kinetic energy is conserved only in elastic collisions.

Chapter 6: System of Particles and Rotational Motion

First, the centre of mass is the point where the whole mass can be treated as concentrated. Next, torque is τ = r × F, and angular momentum is L = r × p. Moment of inertia I plays the role of mass in rotation, so τ = Iα and K = ½Iω². For a disc, I = ½MR², while for a ring, I = MR². Without an external torque, angular momentum is conserved. The parallel-axis and perpendicular-axis theorems help you find I about new axes.

Chapter 7: Gravitation

First, Newton’s law of gravitation gives F = G m₁m₂ / r². The acceleration due to gravity on Earth is g = GM / R², and it decreases with height and depth. Also, Kepler’s three laws describe planetary motion. Meanwhile, the escape velocity is √(2gR), which is about 11.2 km/s for Earth, and the orbital velocity near the surface is √(gR). Gravitational potential energy is −GMm / r.

Chapter 8: Mechanical Properties of Solids

First, stress is force per unit area, and strain is the fractional change in size. Hooke’s law says that stress is proportional to strain within the elastic limit. The ratio gives Young’s modulus, the bulk modulus or the shear modulus, depending on the type of deformation. The stress-strain curve shows the elastic limit, the yield point and the breaking point. Additionally, the elastic energy stored per unit volume is ½ × stress × strain.

Chapter 9: Mechanical Properties of Fluids

First, pressure in a fluid is P = P₀ + ρgh, so it grows with depth. Then Pascal’s law explains the hydraulic lift. Likewise, Archimedes’ principle gives the buoyant force. In streamline flow, the equation of continuity states that Av is constant, and Bernoulli’s theorem links pressure, speed and height. Finally, viscosity resists flow, and surface tension explains drops and capillary rise.

Chapter 10: Thermal Properties of Matter

First, temperature measures how hot a body is, and heat is energy in transit. Next, the linear expansion is ΔL = αLΔT. Then specific heat gives Q = mcΔT, and latent heat gives Q = mL during a change of state. Furthermore, heat moves by conduction, convection and radiation. Newton’s law of cooling and Stefan’s law describe cooling by radiation.

Chapter 11: Thermodynamics

First, the zeroth law defines temperature, and then the first law says ΔU = Q − W. The second law explains why heat does not flow by itself from cold to hot. Moreover, for an ideal gas, the main processes are isothermal, adiabatic, isochoric and isobaric. Finally, the efficiency of a Carnot engine is 1 − T₂/T₁, and no engine can beat it between the same temperatures.

Chapter 12: Kinetic Theory

First, the ideal gas law is PV = nRT. Next, kinetic theory links pressure with the motion of molecules, and the average kinetic energy per molecule is (3/2)kT. Also, the rms speed is √(3RT/M). The law of equipartition gives each degree of freedom ½kT of energy. Therefore, the specific heat of a gas depends on its degrees of freedom.

Chapter 13: Oscillations

First, simple harmonic motion has the equation x = A cos(ωt + φ), and the acceleration is −ω²x. Next, the time period of a spring is T = 2π√(m/k), and for a simple pendulum, T = 2π√(L/g). In SHM, energy keeps shifting between kinetic and potential forms, so the total stays constant. Damped and forced oscillations lead to resonance.

Chapter 14: Waves

First, a wave carries energy without moving the medium. The speed is v = fλ. Transverse waves, such as those on a string, move particles at right angles to the direction of travel. In contrast, longitudinal waves, such as sound, move particles along it. The speed of a wave on a string is √(T/μ). Also, standing waves form nodes and antinodes, and beats occur when two close frequencies mix.

Practicals and Common Mistakes

Practicals carry 30 marks, as they include experiments, a record file, activities, a project and a viva. Regular lab work therefore adds safe marks.

• Students forget units in numericals, so they lose marks even when the value is right.
• Many skip the free-body diagram, which leads to wrong signs.
• Some mix up the formulas for work and power.
• Others use the equations of motion when the acceleration is not constant.

How to Revise Class 11 Physics Notes

Spend the first week on units, kinematics and laws of motion. Next, give a week each to energy, rotation and gravitation. After that, revise bulk matter, thermodynamics and waves. In the last week, solve sample papers. For the next class, see class 12 physics notes, and for an earlier foundation read motion class 9 notes. You can also browse the Class 11–12 Physics category, the Class 11–12 notes hub and electrochemistry class 12 notes.

Wrap-Up

Class 11 physics notes work best as a revision tool after you read each chapter once. Use the marks table to plan, practise diagrams and numericals, and revise formulas daily. Then continue with the Class 11–12 Physics category, or return to the The Note homepage.