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187 simulations · 28 chapters

Physics simulations

Lumi has 187 free interactive Physics simulations for NEET and JEE, on the NCERT syllabus: 94 in Class 11 (14 chapters) and 93 in Class 12 (14 chapters). Each one lets you move a slider, drag a point or change a value and watch the idea respond, and each sits inside a lesson with the notes.

Also: Chemistry (115), Biology (180), Maths (85) · Physics lessons

Units and Measurements · Class 11

6

Which digits does the calculator really know?In: Arithmetic with significant figures Percentage errors add when you multiplyIn: Uncertainty in calculated results Read a vernier callipers and a screw gaugeIn: Uncertainty in calculated results A power multiplies the errorIn: Uncertainty in calculated results Build a quantity from its dimensionsIn: Dimensions and dimensional formulae Find the pendulum's formula from dimensions aloneIn: Deducing relations by dimensions

Motion in a Straight Line · Class 11

7

Average speed is not the average of the speedsIn: Background: position, displacement and distance (prerequisite recap)Negative acceleration, faster car?In: Acceleration Position, velocity and the graphs that record themIn: Reading motion graphs Draw a v–t graph, read the motionIn: Reading motion graphs Thrown up, coming down: one acceleration all the wayIn: Free fall and vertical motion under gravity Distance in the nth secondIn: Free fall and vertical motion under gravity Stopping distance: thinking, then brakingIn: Stopping distance and reaction time

Motion in a Plane · Class 11

6

Resolve a vector: which part gets the cos?In: Resolving vectors into components Adding two displacements at an angleIn: Adding vectors analytically Crossing a riverIn: Adding vectors analytically Dropped or thrown: which lands first?In: Constant acceleration in a plane Throw the ball: speed and angleIn: Projectile motion Why constant speed still means accelerationIn: Uniform circular motion

Laws of Motion · Class 11

10

Same change in momentum, different forceIn: Newton's second law, momentum and impulse Explosion: equal momenta, unequal energiesIn: Conservation of momentum A weight on two stringsIn: Equilibrium of a particle Heavier or lighter in a lift?In: Common forces in mechanics Static friction adjusts itself, up to a limitIn: Friction What pushes the crate forward?In: Friction What keeps a car on a banked curveIn: Circular motion Who supplies the centripetal force?In: Circular motion Friction is not always μNIn: Solving problems in mechanics Connected bodies: one a, two free-body diagramsIn: Solving problems in mechanics

Work, Energy and Power · Class 11

8

Work: only the part of the force along the motion countsIn: Work Work is the area under F–xIn: Work done by a variable force Same ends, different pathsIn: Potential energy and conservative forces Where does the energy go on a rough patch?In: Conservation of mechanical energy Round a vertical circleIn: Conservation of mechanical energy A spring stores ½kx², the area under its F–x lineIn: Potential energy of a spring Power and speed: P = FvIn: Power Collisions: momentum always survives, kinetic energy may notIn: Collisions

System of Particles and Rotational Motion · Class 11

11

Rolling race down an inclineIn: Rigid bodies and their motion Velocities on a rolling wheelIn: Rigid bodies and their motion Find the centre of massIn: Centre of mass Exploding shellIn: Motion of the centre of mass The vector product in 3DIn: Vector product of two vectors Pushing a doorIn: Torque and angular momentum Ladder against a smooth wallIn: Equilibrium of a rigid body See-saw: balance the momentsIn: Principle of moments and centre of gravity Same body, different axisIn: Moment of inertia Spinning up a flywheelIn: Dynamics of rotation Spin chair: pull in, spin upIn: Angular momentum and its conservation

Gravitation · Class 11

7

Equal areas in equal timesIn: The law of areas Where the pulls cancelIn: Universal law of gravitation Build a planetIn: Acceleration due to gravity g inside and outside the earthIn: g above and below the surface Climbing out of a gravity wellIn: Escape speed Launch speed: fall, orbit or escapeIn: Earth satellites Satellite dashboardIn: Earth satellites

Mechanical Properties of Solids · Class 11

4

Stress-strain: load a wire until it breaksIn: Hooke's law and the stress-strain curve Stretch a wire: ΔL = FL/AYIn: Young's modulus Stretch, shear, squeezeIn: Bulk modulus and compressibility Beam sag: flat or on edge?In: Applications of elastic behaviour

Mechanical Properties of Fluids · Class 11

8

Pressure depends only on depthIn: Pascal's law and pressure with depth U-tube with two liquidsIn: Atmospheric and gauge pressure Hydraulic lift: a small push, a large forceIn: Hydraulic machines Venturi tube: speed up, pressure downIn: Bernoulli's principle Torricelli's jet: which hole squirts farthest?In: Bernoulli's principle Terminal velocity: when the forces balanceIn: Viscosity and Stokes' law Drops and bubbles: why the small one pushes harderIn: Angle of contact, drops and bubbles Capillary riseIn: Capillary rise

Thermal Properties of Matter · Class 11

7

Heat a plate with a holeIn: Thermal expansion A lake in winterIn: Anomalous expansion of water and thermal stress Ice in warm water: does it all melt?In: Calorimetry Heating curve: where the heat goesIn: Latent heat Two rods in series: finding the junction temperatureIn: Conduction Blackbody spectrumIn: Radiation and blackbody radiation Newton's law of coolingIn: Newton's law of cooling

Thermodynamics · Class 11

4

First law: where does the heat go?In: First law of thermodynamics Isothermal or adiabatic: same gas, two pathsIn: Adiabatic process A cycle on the P–V diagramIn: Isochoric, isobaric and cyclic processes Carnot engine: the ceiling on efficiencyIn: Carnot engine

Kinetic Theory · Class 11

5

Two flasks joined by a stopcockIn: Partial pressures and the size of a molecule Pressure from molecules hitting the wallsIn: Pressure of an ideal gas from molecular impacts rms speed: same energy, different speedsIn: Kinetic interpretation of temperature Degrees of freedom decide a gas's specific heatIn: Specific heats of gases Mean free path: follow one moleculeIn: Mean free path

Oscillations · Class 11

6

SHM as the shadow of a particle on a circleIn: SHM as the shadow of uniform circular motion Block on a spring: what sets the period?In: Force law for SHM: F = −kx Two springs, one blockIn: Force law for SHM: F = −kx Is it SHM? Plot a against xIn: Force law for SHM: F = −kx Energy in SHM: where K equals UIn: Energy in SHM Simple pendulum: length, g and small swingsIn: The simple pendulum

Waves · Class 11

5

Reading a travelling wave: y = a sin(kx − ωt)In: Displacement relation of a progressive wave Reflection at a fixed end and a free endIn: Reflection and standing waves A string fixed at both ends: which notes can it play?In: Harmonics of strings and pipes Organ pipes: which notes fit in the air column?In: Harmonics of strings and pipes Beats: tuning one string against anotherIn: Beats

Electric Charges and Fields · Class 12

7

Coulomb's law between two charged spheresIn: Coulomb's law Adding the forces from several chargesIn: Forces between multiple charges Field lines of two chargesIn: Electric field lines How fast a dipole's field falls offIn: Electric dipole Torque on a dipole in a uniform fieldIn: Dipole in a uniform external field Flux through a closed surfaceIn: Gauss's law Fields from Gauss's lawIn: Applications of Gauss's law

Electrostatic Potential and Capacitance · Class 12

7

A map of electric potentialIn: Equipotential surfaces Assembling charges, one at a timeIn: Potential energy of a system of charges Two conducting spheres joined by a wireIn: Electrostatics of conductors A parallel plate capacitor on a 100 V batteryIn: Effect of dielectric on capacitance A dielectric slab, battery on or offIn: Effect of dielectric on capacitance Capacitors in series and in parallelIn: Combination of capacitors Charge sharing and the lost energyIn: Energy stored in a capacitor

Current Electricity · Class 12

10

Stretch a wire and watch its resistanceIn: Electric currents in conductors and Ohm's law How fast do electrons really move in a wire?In: Electron drift and where resistivity comes from Resistivity as temperature changesIn: Resistivity of materials and its temperature dependence Two bulbs on the mainsIn: Electrical energy and power Why the terminal voltage is less than the emfIn: Cells, emf and internal resistance Two cells: in series, in parallel, and one reversedIn: Cells in series and in parallel How current divides between branchesIn: Kirchhoff's rules Walking round a loop with KirchhoffIn: Kirchhoff's rules Balance a Wheatstone bridgeIn: Wheatstone bridge Metre bridge: find the unknown resistanceIn: Wheatstone bridge

Moving Charges and Magnetism · Class 12

10

The force on a moving chargeIn: Magnetic field and the Lorentz force Floating a rod on the magnetic forceIn: Force on a current-carrying conductor An electron beam in a magnetic fieldIn: Motion in a magnetic field A charge spiralling along a magnetic fieldIn: Motion in a magnetic field Field at the centre of an arcIn: Field on the axis of a circular loop Inside and outside a thick wireIn: Ampere's circuital law The field inside a solenoidIn: The solenoid Two parallel currentsIn: Force between parallel currents Torque on a coil in a magnetic fieldIn: Torque on a current loop From galvanometer to ammeter and voltmeterIn: The moving coil galvanometer

Magnetism and Matter · Class 12

4

A bar magnet in a uniform fieldIn: Dipole in a uniform field Field on the axis and on the equatorIn: The electrostatic analog What a core does to a solenoidIn: Magnetisation and magnetic intensity Dia, para, ferro: a rod beside a poleIn: Diamagnetism

Electromagnetic Induction · Class 12

7

Three ways to change the fluxIn: Faraday's law of induction Lenz's law: push and pull a magnetIn: Lenz's law and conservation of energy A loop crossing a strip of fieldIn: Lenz's law and conservation of energy A rod sliding on railsIn: Motional emf Emf of a rotating rodIn: Rotating rods and wheels A coil's back emfIn: Self-inductance and magnetic energy A coil turning in a fieldIn: AC generator

Alternating Current · Class 12

7

Why 220 V mains peaks at 311 VIn: RMS values and average power Which leads: V or I?In: AC through an inductor Reactance of a coil and a capacitorIn: AC through a capacitor Adding the voltages in a series LCR circuitIn: Series LCR circuit and impedance Tuning a series LCR circuitIn: Resonance Power factor: where does the power go?In: Power factor An ideal transformerIn: Transformers

Electromagnetic Waves · Class 12

5

Displacement current in a charging capacitorIn: Displacement current A plane electromagnetic waveIn: Nature of electromagnetic waves Which way does the wave go?In: Nature of electromagnetic waves An em wave entering a mediumIn: Speed in vacuum and in media Walk the electromagnetic spectrumIn: The electromagnetic spectrum

Ray Optics and Optical Instruments · Class 12

9

Spherical mirror: where the image formsIn: The mirror equation and magnification Snell's law, the critical angle and total internal reflectionIn: Total internal reflection Thin lens: the same drag, a different formulaIn: Thin lenses: lens maker's formula and thin lens formula A lens in a liquidIn: Thin lenses: lens maker's formula and thin lens formula Two thin lensesIn: Power of a lens and combinations of thin lenses Prism: the angle of minimum deviationIn: Refraction through a prism Thin prism: deviation and coloursIn: Refraction through a prism Compound microscopeIn: Simple and compound microscope Astronomical telescopeIn: Telescope

Wave Optics · Class 12

6

Huygens wavelets at a boundaryIn: Refraction of a plane wave Coherent and incoherent additionIn: Coherent and incoherent addition Young's double-slit fringesIn: Young's double-slit experiment Young's fringes: colour and mediumIn: Young's double-slit experiment Diffraction at a single slitIn: Diffraction at a single slit Polaroids and Malus' lawIn: Malus' law and crossed polaroids

Dual Nature of Radiation and Matter · Class 12

5

Photocurrent and collector potentialIn: Saturation current and stopping potential Photons, not a spreading waveIn: Where the wave picture fails Einstein's photoelectric equationIn: Einstein's photoelectric equation A beam of photonsIn: The photon How long is a matter wave?In: How long is a matter wave?

Atoms · Class 12

6

Counting alpha-particles behind the foilIn: Alpha-particle scattering Alpha-particle scatteringIn: Alpha-particle trajectory Bohr orbits: how r, v and E scale with n and ZIn: Bohr's postulates Electrons into hydrogen: which lines light up?In: Energy levels Hydrogen's line spectrumIn: Line spectra of hydrogen De Broglie's wave round an orbitIn: De Broglie's explanation

Nuclei · Class 12

5

How big is a nucleus?In: Size of the nucleus Weighing a nucleus against its partsIn: Mass defect and binding energy Climbing the binding energy curveIn: Binding energy curve Radioactive decay on the N–Z chartIn: Radioactivity Half-life: random nuclei, a smooth lawIn: Radioactivity

Semiconductor Electronics: Materials, Devices and Simple Circuits · Class 12

5

Doping: electrons and holesIn: Carrier concentration and band levels How the depletion layer formsIn: Formation of a p-n junction p-n junction under biasIn: Diode under forward and reverse bias A one-way valve for currentIn: Diode V-I characteristics From ac to steady dcIn: Half-wave and full-wave rectifiers