Physics (Class 11) — Free Notes (CBSE & HBSE)
Free Class 11 Physics notes — Units and Measurements, Kinematics, Laws of Motion, Work Energy and Power, Rotational Motion, Gravitation, Properties of Solids and Fluids, Thermal Physics, Thermodynamics, Kinetic Theory, Oscillations and Waves — with derivations, solved numericals, MCQs and important questions for CBSE, HBSE, JEE and NEET. Free Class 11 Physics course on SikshaSarovar.
Free, chapter-wise Physics notes for Class 11 on Siksha Sarovar, aligned to NCERT and both CBSE and Haryana Board (HBSE). Covers 14 chapters with explanations, worked examples and board-pattern practice questions.
Chapters covered (14)
- Units and Measurements — Physics begins with measurement. This chapter builds the foundation for the whole syllabus by defining the International System of Units (SI), distinguishing fundamental from…
- Motion in a Straight Line — This chapter introduces kinematics — the description of motion without asking about its cause. Confining ourselves to one dimension, we define distance, displacement, speed,…
- Motion in a Plane — Extending kinematics to two dimensions, this chapter develops the mathematics of vectors — their addition, resolution and unit-vector form — and applies it to two important…
- Laws of Motion — This chapter builds the foundation of dynamics by introducing Newton's three laws of motion, inertia, linear momentum and impulse. It then applies these laws to real situations…
- Work, Energy and Power — This chapter develops the concepts of work done by constant and variable forces, kinetic energy and the work-energy theorem, potential energy and the conservation of mechanical…
- System of Particles and Rotational Motion — This chapter extends mechanics from point particles to extended rigid bodies. It covers the centre of mass and its motion, torque and angular momentum with their conservation…
- Gravitation — Gravitation explains how every mass in the universe attracts every other mass through a single inverse-square law. This chapter builds from Kepler's empirical planetary laws to…
- Mechanical Properties of Solids — Mechanical Properties of Solids studies how solids deform under applied forces and recover their shape. It defines elasticity and plasticity, then quantifies deformation through…
- Mechanical Properties of Fluids — Mechanical Properties of Fluids covers both fluids at rest and in motion. The hydrostatics part introduces pressure, Pascal's law and its applications (hydraulic lift and brakes),…
- Thermal Properties of Matter — This chapter studies how matter responds to heat: the distinction between temperature and heat, thermal expansion of solids/liquids/gases, specific and latent heat through…
- Thermodynamics — Thermodynamics studies energy transformations between heat and work in macroscopic systems. This chapter introduces thermal equilibrium and the zeroth law, internal energy, the…
- Kinetic Theory — Kinetic Theory explains the macroscopic behaviour of gases from the motion of their molecules. It develops the molecular nature of matter, the ideal gas equation, the derivation…
- Oscillations — Oscillations introduces periodic and oscillatory motion, with simple harmonic motion (SHM) as the central idea. This chapter develops the kinematics of SHM (displacement,…
- Waves — Waves studies the propagation of disturbances that carry energy without transporting matter. The chapter classifies waves as transverse or longitudinal, develops the basic wave…
Units and Measurements: Physical Quantities, SI Units and Derived Units
What is a Physical Quantity?
A physical quantity is any quantity that can be measured. Every measurement has two parts: a numerical value (magnitude) and a unit. We write a measured quantity as:
Physical quantity = numerical value x unit, i.e. Q = n u
If the unit u is made larger, the number n becomes smaller, so n u = constant. This is why 1 m of cloth and 100 cm of cloth describe the same length.
Fundamental vs Derived Units
- Fundamental (base) quantities are independent and cannot be expressed in terms of others.
- Derived quantities are obtained by combining base quantities (e.g. speed = length / time).
The Seven SI Base Units
The SI system (Systeme International d'Unites) is the internationally agreed system used throughout Physics.
| Base quantity | SI unit | Symbol |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Electric current | ampere | A |
| Temperature | kelvin | K |
| Amount of substance | mole | mol |
| Luminous intensity | candela | cd |
There are also two supplementary units: the radian (rad) for plane angle and the steradian (sr) for solid angle.
Some Derived Units
| Quantity | Relation | Derived unit |
|---|---|---|
| Area | length x length | m^2 |
| Speed | length / time | m s^-1 |
| Acceleration | speed / time | m s^-2 |
| Force | mass x acceleration | kg m s^-2 = newton (N) |
| Work / Energy | force x distance | kg m^2 s^-2 = joule (J) |
CBSE/HBSE trap: The unit of mass is the kilogram, not the gram. Many students lose marks writing the base unit of mass as 'g'.
Measuring Very Large and Very Small Lengths
- Parallax method is used to measure the distance of nearby stars and the size of astronomical bodies.
- Convenient large units: 1 astronomical unit (AU) = 1.496 x 10^11 m; 1 light year = 9.46 x 10^15 m; 1 parsec = 3.08 x 10^16 m.
- Convenient small units: 1 angstrom = 10^-10 m; 1 fermi = 10^-15 m.
Frequently asked questions
Are these Physics notes free?
Yes — all Physics notes on Siksha Sarovar are free to read, no account required.
Do the notes follow CBSE and HBSE?
Yes. Notes are NCERT-aligned and include both CBSE and Haryana Board (HBSE) exam guidance, important questions and MCQs.
Can I prepare for board exams here?
Yes — each chapter includes key concepts, formulas, important questions and practice MCQs for board exam revision.