THE LESSON LIBRARY / PHYSICS
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Oscillations
7 free physics experiments and lesson notes for Oscillations, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationOverlap incident and reflected pulses
Where pulses overlap their displacements add algebraically. They then pass through with their original shapes in a linear medium. A pulse reflected at a fixed end inverts; a…
Explore lesson Physicsvirtual labPaper scale least count
Choose the scale span and number of equal divisions before reading an object. Smaller divisions improve resolution only when the marks can be distinguished.
Explore lesson PhysicssimulationParallel-plate capacitance
Increase area or permittivity to store more charge per volt. Increase gap to reduce capacitance. Connected and isolated cases obey different charge constraints.
Explore lesson Physicsvirtual labParallelogram force apparatus
Two measured string tensions add as vectors. A third string placed opposite the resultant balances the knot when its tension matches the resultant magnitude.
Explore lesson PhysicschapterParticles & Rotational Motion
10 free physics experiments and lesson notes for Particles & Rotational Motion, with model limits, worked examples and Tamil explanations.
Explore lesson Physicsvirtual labPendulum energy dissipation
Track successive maximum swings to see energy lost to damping. Energy falls with the square of amplitude; the light-damping period is approximated by the small-angle undamped…
Explore lesson Physicsvirtual labPendulum length and stopwatch
Time many cycles to reduce the effect of stopwatch resolution. Adjust bob mass to confirm the ideal period is independent of mass; use the length to the centre of the bob.
Explore lesson PhysicssimulationPhotoelectric collecting curves
A retarding collector removes low-energy electrons first, reaching zero current at the stopping potential. An accelerating collector collects the available electrons, producing…
Explore lesson PhysicssimulationPhotoelectric threshold
A photon must supply the work function before an electron can escape. Its remaining energy is the maximum kinetic energy. Greater intensity increases emission rate above…
Explore lesson PhysicssimulationPhotons build an interference pattern
Each photon creates a localized detection while many detections reveal an interference probability pattern. Wavelength determines the energy and momentum of each photon, not…
Explore lesson Physicstopic indexPhysics lesson notes and formula index
All 260 free physics lessons, formulas and model limits, with English and Tamil explanations, organised by Class 11, Class 12 and practical apparatus.
Explore lesson PhysicssectionPhysics simulations and virtual labs
260 free interactive Class 11 and 12 physics experiments and virtual practical labs, with English and Tamil explanations.
Explore lesson Physicsvirtual labPith-ball polarization and contact
A neutral ball is attracted by the nonuniform field through polarization. In the imposed contact state it receives the rod’s sign and repels. Increasing separation rapidly…
Explore lesson PhysicssimulationPlane mirror reflection
The reflected ray remains in the plane of incidence and makes the same angle with the normal. Backward extensions locate an upright virtual image as far behind the mirror as the…
Explore lesson PhysicssimulationPoint-charge field and field lines
A positive test charge defines field direction. Positive sources have outward radial fields; negative sources have inward fields. The graph records that signed radial direction.
Explore lesson PhysicssimulationPolarizers and Brewster angle
The first polarizer selects a transverse direction. The analyzer passes the squared projection along its axis. At Brewster incidence, reflected and refracted rays are…
Explore lesson Physicsvirtual labPost-office-box resistance balance
Choose ratio-arm plugs, adjust the standard box and watch galvanometer direction reverse through zero. A null means the bridge midpoint potentials agree. Use the chosen ratio to…
Explore lesson PhysicschapterPotential & Capacitance
8 free physics experiments and lesson notes for Potential & Capacitance, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationPotential of charges and dipoles
Potentials add as scalars while fields add as vectors. An opposite-charge pair has zero potential on its perpendicular bisector but generally a nonzero field there.
Explore lesson PhysicssimulationPower factor and reactive current
Voltage and current out of phase exchange energy with L and C. Their reactive components do not contribute net energy over a whole cycle; R consumes real power.
Explore lesson PhysicschapterPractical apparatus
65 free physics experiments and lesson notes for Practical apparatus, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationPrecision ruler
A ruler can only distinguish its marked divisions. Its least count is the smallest interval it can read. A finer scale reduces rounding uncertainty, but does not automatically…
Explore lesson PhysicssimulationPrism deviation and dispersion
Two refractions turn the ray through a prism. Symmetric passage gives minimum deviation. Different refractive indices for different colours create dispersion, with a higher index…
Explore lesson Physicsvirtual labPrism minimum-deviation reading
Sweep incidence and identify the lowest deviation before using the prism-index formula. An angular zero error shifts the readings. An arbitrary deviation substituted for the…
Explore lesson PhysicssimulationProbe gravity inside and above Earth
Above Earth, gravity falls by the inverse-square law. Inside a uniform sphere only the mass enclosed by the probe radius contributes, so gravity decreases linearly to zero at the…
Explore lesson PhysicssimulationProject circular motion into SHM
A rotating point projects onto a diameter as simple harmonic motion. The projection slows at the endpoints and is fastest at the centre. Its acceleration always points toward the…
Explore lesson Physicsvirtual labProjectile range and protractor
Keep launch speed constant and sweep the protractor angle. Range peaks at 45° when launch and landing heights match. Complementary angles give equal ranges.
Explore lesson PhysicssimulationProjectile trajectory
Resolve the launch velocity into horizontal and vertical components. With no air resistance, horizontal velocity stays constant while vertical velocity decreases by g each…
Explore lesson PhysicssimulationPull rotating masses inward
With no external torque, angular momentum remains constant. Bringing mass closer to the rotation axis reduces inertia and increases angular speed. The pulling mechanism supplies…
Explore lesson PhysicschapterRay Optics & Optical Instruments
9 free physics experiments and lesson notes for Ray Optics & Optical Instruments, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationRC, LR and LC transients
Switch among capacitor charging, inductor current rise and ideal energy exchange in an LC circuit. RC and LR approach a steady state; ideal LC continues oscillating.
Explore lesson PhysicssimulationReactance, impedance and phasors
Inductor reactance grows with frequency; capacitor reactance falls. Their signed difference determines phase, and the resistor sets the in-phase component.
Explore lesson PhysicssimulationReference frames
Position and velocity need an observer. The roadside origin stays at x = 0. The bus origin moves at the bus velocity, so its coordinates subtract the bus displacement. Both…
Explore lesson PhysicssimulationRelative velocity
Relative position compares the car with the bus rather than with the road origin. Its rate of change is the car velocity minus the bus velocity. If this relative velocity is…
Explore lesson PhysicssimulationResistance combinations
Series elements carry the same current; parallel branches see the same voltage. The equivalent parallel resistance is below the smallest branch resistance.
Explore lesson PhysicssimulationResistivity and temperature
Length and cross-section control resistance independently of the material resistivity. The linear temperature relation is valid over a limited range.
Explore lesson PhysicssimulationResize a satellite orbit
Gravity supplies centripetal acceleration in a circular orbit. Higher orbits have lower speed but greater circumference, so the period grows. Their total orbital energy is less…
Explore lesson PhysicssimulationResolve a force
Rectangular components are the projections of a vector onto perpendicular axes. With θ measured from +x, the adjacent projection is F cos θ and the opposite projection is F sin…
Explore lesson Physicsvirtual labResonance-tube sound speed
Slide the water level to change the closed air column. Locate two resonance peaks; their separation removes the common open-end correction. Peak width is an illustrative…
Explore lesson PhysicssimulationRoll a ring, cylinder or sphere
Gravitational energy becomes both translational and rotational kinetic energy. Bodies with a smaller shape factor need less rotational energy per unit speed and accelerate…
Explore lesson PhysicssimulationRutherford alpha scattering
Most alpha particles pass with small deflection; near passes can turn through large angles. A compact positive nucleus explains rare backward scattering. Larger impact parameter…
Explore lesson Physicsvirtual labScrew gauge
A screw advances by its pitch in one full turn. Dividing that turn into many thimble marks gives a small least count. Include visible half-millimetre marks on the sleeve before…
Explore lesson PhysicssimulationSelf and mutual inductance
Inductance measures flux linkage per ampere. More turns increase self-inductance quadratically. Mutual inductance also depends on how well the two coils share flux.
Explore lesson PhysicschapterSemiconductor Electronics
7 free physics experiments and lesson notes for Semiconductor Electronics, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationSeparate two attracting masses
Every pair of masses attracts. The inverse-square relationship means doubling separation reduces the force to one quarter. Changing either mass scales the force linearly.
Explore lesson PhysicssimulationSeries and parallel capacitors
Series capacitors share charge and split voltage inversely with capacitance. Parallel capacitors share voltage and their charges add.
Explore lesson PhysicssimulationSeries and parallel cells
Series cells raise EMF but also add internal resistance. Identical parallel cells retain one-cell EMF while reducing internal resistance. Compare small and large loads.
Explore lesson PhysicssimulationSeries LCR resonance
Near resonance, inductive and capacitive reactances cancel. Resistance limits the current and controls peak width; small resistance makes a sharper resonance.
Explore lesson PhysicssimulationSet the temperature limits of an engine
A heat engine must reject some heat to the cold reservoir. The reversible Carnot efficiency depends only on absolute reservoir temperatures. Increasing their temperature…
Explore lesson PhysicssimulationShift a blackbody spectrum
Hotter bodies emit much more power and peak at shorter wavelengths. Stefan law controls total power through T⁴; Wien law locates the spectral peak through 1/T. The curve uses…
Explore lesson PhysicssimulationShift the rotation axis
Moving an axis parallel to the central axis adds Md² to inertia. For a thin planar body, the perpendicular-axis theorem adds two orthogonal in-plane inertias. These theorems…
Explore lesson PhysicssimulationSI unit builder
A physical quantity combines a number and a unit. SI has seven base units: metre, kilogram, second, ampere, kelvin, mole and candela. Derived units combine them: a newton is kg m…
Explore lesson PhysicssimulationSignificant figures
Leading zeros locate the decimal point; they are not significant. Zeros between significant digits count, as do trailing zeros explicitly written after a decimal point. An…
Explore lesson PhysicssimulationSingle-slit diffraction
Different parts of one aperture interfere. A narrow aperture spreads light more widely. The central maximum lies between the first minima and is twice the approximate width of…
Explore lesson Physicsvirtual labSliding and rolling friction
Tilt a surface until gravity exceeds the stated drag threshold. The rolling option models effective rolling resistance rather than detailed rotational inertia.
Explore lesson Physicsvirtual labSlit diffraction screen probe
Sweep the intensity probe and find the first minima on either side. Their separation measures central-maximum width. Repeat after changing slit opening while keeping wavelength…
Explore lesson PhysicssimulationSlope & signed area
Differentiating a position graph gives velocity; differentiating velocity gives acceleration. Integrating the signed velocity area gives displacement, while integrating…
Explore lesson Physicsvirtual labSolid and liquid calorimetry
Choose a solid sample or hot water and mix with cooler water. Include the calorimeter heat capacity so heat balance predicts the correct final temperature.
Explore lesson Physicsvirtual labSonometer length and tension
Move sonometer bridges to set vibrating length and change the tension load. Match a tuning-fork frequency to the string resonance; frequency varies inversely with length and as…
Explore lesson PhysicssimulationSpherical mirror images
A concave mirror can give a real inverted image or a virtual upright image depending on object position. A convex mirror gives a reduced virtual image. The focal-position limit…
Explore lesson Physicsvirtual labSpherometer curvature
The three legs define an equilateral triangle and the central screw measures sagitta h. Correct the flat-plate zero before finding a spherical surface radius.
Explore lesson PhysicssimulationSpring and potential energy
A spring stores energy as work is done against its restoring force. Because the force increases with deformation, spring energy is ½kx², not kx². Released on a frictionless…
Explore lesson Physicsvirtual labSpring load–extension apparatus
Add loads and plot extension against force. A straight line through the corrected origin is the Hooke-law range. No-load inference is intentionally undefined and indicated as zero.
Explore lesson PhysicssimulationStick, slide and roll
Static friction matches the applied push up to a maximum μsN. It does not always equal that maximum. Above the threshold, a block starts sliding and resistance becomes μkN.…
Explore lesson PhysicssimulationStore energy in a wire and beam
The force rises from zero as a wire extends or a beam bends, so stored work is half final force times deflection. Beam geometry enters through its cross-section second moment…
Explore lesson PhysicssimulationStretch a two-sided liquid film
Creating more liquid surface requires energy. A soap film has two faces, so its force and energy contain a factor of two. Contact angle controls the sign of the wetting term and…
Explore lesson PhysicssimulationStretch within the elastic range
Stress is force per area; strain is extension divided by original length. Within the linear elastic region the stress-strain slope is Young modulus. Releasing the load recovers…
Explore lesson PhysicssimulationStrike a hinged rod
During a brief collision the hinge can exert an impulse, so linear momentum of particle plus rod need not be conserved. Its moment about the hinge is zero, allowing angular…
Explore lesson PhysicssimulationSubmerge a floating object
Buoyancy equals the weight of displaced liquid. At equilibrium a floating object displaces its own weight, rather than its whole volume. Objects denser than the liquid cannot…
Explore lesson PhysicssimulationSuperposition and charged ring
Point-charge vectors add component by component. A uniformly charged ring is the continuous limit: transverse components cancel on its axis. Select both sources to compare.
Explore lesson PhysicssimulationTangent & inward acceleration
Velocity includes direction. On a circle its magnitude stays constant but its direction continually changes. The velocity is tangent to the circle, while acceleration points…
Explore lesson Physicsvirtual labTangent-galvanometer alignment
Align the coil plane with the magnetic meridian, then infer horizontal Earth field from the deflection. Deliberate misalignment demonstrates why the perpendicular-field condition…
Explore lesson PhysicssimulationTest the escape-energy threshold
Escape occurs when the launch kinetic energy cancels or exceeds the negative gravitational potential energy. The escape speed depends on the central body and launch radius but…
Explore lesson PhysicschapterThermal Properties of Matter
10 free physics experiments and lesson notes for Thermal Properties of Matter, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicschapterThermodynamics
8 free physics experiments and lesson notes for Thermodynamics, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationTIR and fibre guidance
Total internal reflection needs both a higher starting index and incidence beyond the critical angle. Repeated reflections can guide light through an ideal optical fibre.
Explore lesson PhysicssimulationTrace a pressure-volume cycle
Internal energy returns to its starting value over a cycle, but net work can be nonzero. The signed area inside a PV loop measures that work. A clockwise loop produces positive…
Explore lesson PhysicssimulationTrace an equal-area orbit
An ellipse has the Sun at a focus. The planet moves faster near the Sun and slower farther away, sweeping equal areas in equal times. Increasing the semi-major axis increases the…
Explore lesson PhysicssimulationTrace buoyancy-driven circulation
Heating from below makes lower fluid less dense, creating buoyancy. Viscosity and thermal diffusion oppose the instability. The circulation appears only when the Rayleigh number…
Explore lesson PhysicssimulationTrack cooling toward ambient
Newton cooling makes the rate proportional to the current temperature difference. Cooling is fastest initially and slows as the body approaches ambient. If initially colder, the…
Explore lesson PhysicssimulationTrack energy balance
Without friction, gravitational potential turns into kinetic energy and their sum stays constant. With friction, mechanical energy decreases but the energy balance includes…
Explore lesson PhysicssimulationTrack energy through one oscillation
At turning points the oscillator stores all energy as spring potential energy. At equilibrium it has maximum kinetic energy. Their sum stays constant even though each part…
Explore lesson Physicsvirtual labTransformer turns and RMS meters
Compare voltage ratio with counted turns. A voltage step-up increases secondary voltage but decreases primary-to-secondary current ratio for conserved power. A load is needed to…
Explore lesson PhysicssimulationTransformer turns ratio
A transformer uses changing shared flux. Raising voltage reduces available current for a given transmitted power. Efficiency accounts for a lumped input-power loss.
Explore lesson PhysicssimulationTransverse electromagnetic wave
E and B oscillate in perpendicular directions, both transverse to propagation. Their peaks occur together in a vacuum plane wave. Change time to shift the field pattern.
Explore lesson Physicsvirtual labTravelling-microscope slab readings
Focus successively on the lower mark, upper surface and apparent lower mark. Differences remove the arbitrary reference reading. Resolution and focus error influence the…
Explore lesson PhysicssimulationTune a small-angle pendulum
At small angles the pendulum has a restoring acceleration proportional to angular displacement. A longer string increases period, while greater gravity decreases it. The ideal…
Explore lesson PhysicssimulationTwist a torsional pendulum
Angular SHM occurs when torque is proportional and opposite to angular displacement. A larger rotational inertia gives a longer period; a stronger torsion constant gives a…
Explore lesson PhysicssimulationTwo routes, different losses
Gravity is conservative: its work depends only on the initial and final heights. The two routes have identical gravity work even when one climbs higher. A resisting force does…
Explore lesson PhysicssimulationUncertainty laboratory
Separate the best estimate from its uncertainty. For sums and differences, absolute worst-case bounds add. Products, quotients and powers often use first-order relative error…
Explore lesson PhysicssimulationUniform vs changing motion
Cart A covers equal displacements in equal time intervals because its velocity is constant. Cart B has a changing velocity when its acceleration is nonzero. Their position graphs…
Explore lesson PhysicssimulationUnit conversion
Changing a unit changes the numerical value, not the physical quantity. Convert through the common base unit. Area scales with the square of a length factor; volume scales with…
Explore lesson PhysicschapterUnits & Measurements
7 free physics experiments and lesson notes for Units & Measurements, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationVector & unit vector
A scalar has magnitude only. A vector also has a direction. Temperature is a scalar; displacement is a vector. Rotating a vector can preserve its magnitude while changing its…
Explore lesson Physicsvirtual labVernier caliper
A vernier compares two scales with slightly different divisions. Ten vernier divisions span nine millimetres, so adjacent divisions differ by 0.1 mm. The coinciding line…
Explore lesson PhysicssimulationWatch sideways contraction
An ordinary stretched wire contracts sideways. Poisson ratio compares this negative lateral strain with the positive longitudinal strain. At small strain, the volume change is…
Explore lesson PhysicschapterWave Optics
5 free physics experiments and lesson notes for Wave Optics, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicschapterWaves
8 free physics experiments and lesson notes for Waves, with model limits, worked examples and Tamil explanations.
Explore lesson Physicsvirtual labWax freezing plateau
Follow cooling through a state change. Heat continues leaving during freezing while temperature remains near the model freezing point, because latent heat is released.
Explore lesson PhysicssimulationWheatstone and metre bridge
Find zero detector voltage in the bridge. A uniform metre wire turns a resistance ratio into a length ratio. Ratio arms in a post-office box use the same null principle.
Explore lesson PhysicssimulationWire force and parallel currents
An external B acts on a current-carrying wire. Two long parallel wires also exert forces on one another: agreeing current directions attract; opposite directions repel.
Explore lesson Physicsvirtual labWire probe potential gradient
Move the probe along the same wire and compare potential drop with distance. Uniform resistance per length gives a straight-line voltage gradient. The rheostat changes current…
Explore lesson Physicsvirtual labWire resistivity VI graph
Read voltage and current at several low-current settings and obtain resistance from the VI slope. Diameter measured with a screw gauge determines area; correct the ammeter zero.
Explore lesson PhysicssimulationWork under a force curve
Only the component parallel to displacement contributes to work. A constant force gives a rectangular area. A linearly varying force adds a triangular contribution. Area below…
Explore lesson PhysicschapterWork, Energy & Power
8 free physics experiments and lesson notes for Work, Energy & Power, with model limits, worked examples and Tamil explanations.
Explore lesson PhysicssimulationX-ray continuum and target lines
The maximum electron energy sets the short-wavelength cutoff. Target atomic number sets characteristic transitions. Raising tube voltage moves the cutoff without shifting a given…
Explore lesson PhysicssimulationYoung double-slit fringes
Path difference changes across the screen. Constructive and destructive interference repeat at equal spatial intervals in the small-angle limit. Wavelength and screen distance…
Explore lesson Physicsvirtual labYoung modulus wire apparatus
Use a long thin wire to make elastic extension measurable. Diameter enters as a square, so its measurement strongly affects the inferred modulus.
Explore lesson PhysicssimulationZener load regulation
The series resistor limits available current. A light load allows excess current through the Zener and clamps output. A heavy load can consume all available current, making the…
Explore lesson Physicsvirtual labZener reverse-breakdown meters
Raise the reverse source through breakdown while monitoring both meters. The diode voltage clamps approximately while resistor voltage and current increase. Compare two resistor…
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