# NEET IIT Lab Physics

> Free interactive physics learning for students: 260 labs, 28 Class 11 and Class 12 chapters, 65 practical activities, English and Tamil explanations. Original KalviYogi / 369 Tesla / Edunivra credits are preserved. Teaching content and exam scope await teacher review.

- [Physics simulations](https://neetiitlab.com/physics/)
- [All topic notes](https://neetiitlab.com/physics/topics/)

- [SI unit builder](https://neetiitlab.com/physics/experiments/si/): 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 s⁻². A named derived unit is not an eighth base unit. A unit system chooses its standards: SI mechanics uses metre, kilogram and second; CGS uses centimetre, gram and second. Measurement lets us compare a quantity with a shared standard.
- [Unit conversion](https://neetiitlab.com/physics/experiments/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 its cube. This laboratory includes exact prefix and time conversion factors, not temperature offsets.
- [Precision ruler](https://neetiitlab.com/physics/experiments/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 remove calibration or reading errors.
- [Significant figures](https://neetiitlab.com/physics/experiments/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 integer such as 1200 is ambiguous without a precision statement; scientific notation removes that ambiguity.
- [Uncertainty laboratory](https://neetiitlab.com/physics/experiments/uncertainty/): 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 rules when errors are small. This lab also calculates exact intervals so the approximation is visible.
- [Dimensional balance](https://neetiitlab.com/physics/experiments/dimensions/): Every physical equation must have matching dimensions on both sides. Force has dimensions M L T⁻². Multiplying mass by acceleration produces the same dimensions; multiplying mass by velocity does not. Dimensions describe the quantity type and do not depend on the selected unit.
- [Dimensional applications](https://neetiitlab.com/physics/experiments/applications/): Assume a pendulum period depends only on length l and gravity g through T = C lᵃ gᵇ. Matching time dimensions gives a = 1/2 and b = −1/2. It cannot determine C. The ideal small-angle pendulum has C = 2π; that result comes from its dynamics.
- [Reference frames](https://neetiitlab.com/physics/experiments/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 descriptions refer to the same walker at the same time.
- [Distance & displacement](https://neetiitlab.com/physics/experiments/distance/): Position states where the walker is relative to an origin. Displacement is final position minus starting position. Distance adds the lengths of all travelled parts. Reversing direction can cancel displacement while distance continues to increase.
- [Average & instantaneous](https://neetiitlab.com/physics/experiments/velocity/): The secant joining two positions gives average velocity over that interval. The tangent at the current time gives instantaneous velocity. Speed is the magnitude of instantaneous velocity, while average speed uses the full distance travelled. A varying acceleration makes the distinction between a secant and tangent visible.
- [Uniform vs changing motion](https://neetiitlab.com/physics/experiments/race/): 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 can cross even when their slopes differ.
- [Constant acceleration](https://neetiitlab.com/physics/experiments/acceleration/): Acceleration is the rate of change of velocity. When velocity and acceleration have opposite signs, speed decreases until velocity reaches zero. Continued acceleration then starts motion in the opposite direction. The displacement equations use signed displacement.
- [Slope & signed area](https://neetiitlab.com/physics/experiments/calculus/): Differentiating a position graph gives velocity; differentiating velocity gives acceleration. Integrating the signed velocity area gives displacement, while integrating acceleration gives the change in velocity. Initial position and initial velocity supply the constants needed to reconstruct the journey.
- [Relative velocity](https://neetiitlab.com/physics/experiments/relative/): 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 positive, the car closes an initial gap behind the bus. Changing the observer leaves their relative position unchanged.
- [Vector & unit vector](https://neetiitlab.com/physics/experiments/vectors/): 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 components. The unit vectors î and ĵ select the positive coordinate directions.
- [Head-to-tail vectors](https://neetiitlab.com/physics/experiments/vector-addition/): Move the tail of the second arrow to the head of the first. The resultant joins the original tail to the final head. Subtracting B means adding −B. A negative scale factor reverses direction; its absolute value scales length. Equal vectors have equal components, regardless of where they are drawn.
- [Resolve a force](https://neetiitlab.com/physics/experiments/components/): 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 θ. The force equals the vector sum of those components. Rotating through a quadrant changes component signs.
- [Dot & cross products](https://neetiitlab.com/physics/experiments/products/): The dot product is a scalar measuring alignment: positive for acute angles, zero at 90°, negative for obtuse angles. The cross product is a vector perpendicular to both inputs. Its z-component is signed in this plane. The right-hand rule gives its direction, and reversing the order reverses that direction.
- [Independent x & y motion](https://neetiitlab.com/physics/experiments/plane-motion/): Uniform motion in a plane has constant horizontal and vertical velocity components. Each coordinate evolves as a separate straight-line equation, but both use the same elapsed time. Combining the coordinates gives a straight path. Changing one component changes the path direction and speed.
- [Projectile trajectory](https://neetiitlab.com/physics/experiments/projectile/): Resolve the launch velocity into horizontal and vertical components. With no air resistance, horizontal velocity stays constant while vertical velocity decreases by g each second. At the apex the vertical velocity is zero; horizontal velocity usually remains. The ball follows a parabola until ground contact.
- [Tangent & inward acceleration](https://neetiitlab.com/physics/experiments/circular-motion/): 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 inward. The two are perpendicular. Doubling speed quadruples the centripetal acceleration at the same radius.
- [Inertia trolleys](https://neetiitlab.com/physics/experiments/inertia-trolleys/): Mass measures resistance to a change in velocity. A net force accelerates a trolley; the same force produces less acceleration on a larger mass. Remove the push and both continue at their own constant velocities. Zero net force permits rest or uniform motion.
- [Impulse and contact time](https://neetiitlab.com/physics/experiments/impulse-area/): Momentum is mv. Newton’s second law links force to its rate of change; integrating force over time gives impulse. Both the short and long triangular force pulses remove the same incoming momentum. The broader pulse needs a lower peak but produces a longer stopping distance.
- [Action and reaction](https://neetiitlab.com/physics/experiments/third-law-skaters/): Each skater exerts a force on the other. The two forces are equal and opposite at the same instant, but act on different bodies. They therefore cannot cancel in the force equation for one skater. The lighter skater changes velocity more; their momentum changes remain equal and opposite.
- [Momentum after release](https://neetiitlab.com/physics/experiments/spring-cart-release/): The spring pushes both carts internally. With no external impulse, total momentum remains its initial value, even while spring energy becomes kinetic energy. From rest, momenta are opposite. With an initial common drift, the centre of mass continues moving at that drift velocity.
- [Balance three forces](https://neetiitlab.com/physics/experiments/concurrent-equilibrium/): Equilibrium requires the net force to vanish in every direction. Three large pulls can balance because their vector components cancel. Changing a magnitude or direction usually leaves a resultant. The required third force is the negative of the sum of the first two.
- [Stick, slide and roll](https://neetiitlab.com/physics/experiments/friction/): 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. Wheels have a smaller effective rolling resistance in this simplified trolley comparison.
- [Dry or lubricated](https://neetiitlab.com/physics/experiments/lubrication-race/): A lubricant can reduce direct contact between rough surfaces and change their friction. Here you choose lower coefficients and compare identical blocks. A weaker push may move the lubricated block while the dry block remains stuck. Real lubricants also produce viscous resistance; that additional behavior is outside this model.
- [Level and banked roads](https://neetiitlab.com/physics/experiments/banked-road/): A vehicle needs inward net force mv²/r. On a level road static friction supplies it. On a banked road the tilted normal contributes. At the design speed no friction is needed; below or above it friction acts in opposite directions. Grip is possible only when the required friction is within μN.
- [Apparent weight in a lift](https://neetiitlab.com/physics/experiments/apparent-weight-lift/): A scale measures the normal support force. Upward acceleration requires N greater than mg; downward acceleration requires less. During free fall both lift and person accelerate at −g, so the support force vanishes. In the accelerating lift frame a pseudo-force −ma restores the equilibrium-form equation.
- [Work under a force curve](https://neetiitlab.com/physics/experiments/variable-force-work/): 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 zero subtracts from work; a force perpendicular to displacement does no work.
- [Braking and kinetic energy](https://neetiitlab.com/physics/experiments/braking-work-energy/): The work-energy theorem connects net work to the change in kinetic energy. A brake does negative work because its force opposes displacement. The stopping distance is initial kinetic energy divided by brake force, so doubling speed quadruples stopping distance when mass and force are fixed.
- [Equal work, different power](https://neetiitlab.com/physics/experiments/lifting-power/): Work is energy transferred. Power is the rate of that transfer. Both lifts raise the same mass through the same height and therefore do equal work against gravity. The lift with shorter duration needs greater average power. At constant speed the force is mg, giving P = mgv.
- [Spring and potential energy](https://neetiitlab.com/physics/experiments/spring-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 platform, this energy alternates between elastic potential and kinetic forms. A raised platform adds constant gravitational potential mgh relative to the ground.
- [Two routes, different losses](https://neetiitlab.com/physics/experiments/conservative-paths/): 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 negative work along every part of the journey, so its energy loss depends on total length. External work for slow transport supplies both the potential-energy increase and the dissipated energy.
- [Track energy balance](https://neetiitlab.com/physics/experiments/track-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 dissipated thermal energy. A large enough resistance can prevent starting or stop an initially moving slider before the bottom.
- [Keep a vertical loop taut](https://neetiitlab.com/physics/experiments/vertical-loop-tautness/): Energy determines how speed changes while the bob climbs. Tension also must remain non-negative because a string cannot push. At the top the minimum taut speed is √(gr), which requires bottom speed √(5gr). A slower bob can turn back or lose string tension before reaching the top; the preview stops at that first limit.
- [Collisions in 1D and 2D](https://neetiitlab.com/physics/experiments/collisions/): An isolated collision conserves vector momentum. Restitution specifies how relative normal velocity changes; e = 1 is elastic and e = 0 removes relative normal motion. For smooth oblique contact only the normal components change, while tangential components remain unchanged. With no approaching normal motion the model applies no impulse.
- [Find the balance point](https://neetiitlab.com/physics/experiments/centre-of-mass/): The centre of mass weights each position by its mass. A uniform rod contributes its own midpoint. Move either particle or change its mass to move the balance point toward the heavier side.
- [Follow a collision centre](https://neetiitlab.com/physics/experiments/centre-of-mass-motion/): Internal collision forces change the carts individually, while their centre of mass continues along a straight line at a constant velocity. The sticking collision dissipates kinetic energy but conserves momentum.
- [Move the force lever](https://neetiitlab.com/physics/experiments/torque-lever/): Torque measures the turning effect of a force. Only its component perpendicular to the lever turns the body. A force along the lever produces zero torque even when its magnitude is large.
- [Pull rotating masses inward](https://neetiitlab.com/physics/experiments/angular-momentum-conservation/): 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 the extra kinetic energy.
- [Can the ladder stay balanced?](https://neetiitlab.com/physics/experiments/ladder-equilibrium/): Taking moments about the foot determines the horizontal wall reaction. The floor must provide equal horizontal friction and support the weight. A steeper ladder needs less friction in this ideal model.
- [Accelerate a rotating wheel](https://neetiitlab.com/physics/experiments/rotational-equations/): A constant net torque gives constant angular acceleration for a body with fixed inertia. The rotational equations mirror constant-acceleration linear motion, with torque replacing force and inertia replacing mass.
- [Compare shapes around an axis](https://neetiitlab.com/physics/experiments/inertia-shapes/): Moment of inertia depends on how mass is distributed relative to an axis. More mass farther from the axis increases I. Radius of gyration is the single effective radius that reproduces I= Mk².
- [Shift the rotation axis](https://neetiitlab.com/physics/experiments/axes-theorems/): 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 refer to different axis relationships.
- [Roll a ring, cylinder or sphere](https://neetiitlab.com/physics/experiments/rolling-race/): Gravitational energy becomes both translational and rotational kinetic energy. Bodies with a smaller shape factor need less rotational energy per unit speed and accelerate faster. The no-slip condition is v=ωr.
- [Strike a hinged rod](https://neetiitlab.com/physics/experiments/hinged-rod-collision/): 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 momentum about that point to determine the final rotation.
- [Separate two attracting masses](https://neetiitlab.com/physics/experiments/universal-gravity/): 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.
- [Trace an equal-area orbit](https://neetiitlab.com/physics/experiments/kepler-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 period according to T² proportional to a³.
- [Probe gravity inside and above Earth](https://neetiitlab.com/physics/experiments/gravity-altitude-depth/): 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 centre.
- [Explore the gravitational energy well](https://neetiitlab.com/physics/experiments/gravity-potential/): Gravitational potential is potential energy per unit probe mass. With zero at infinity it is negative at finite distance; work must be supplied to move the probe outward. Field magnitude decreases faster with radius than potential magnitude.
- [Test the escape-energy threshold](https://neetiitlab.com/physics/experiments/escape-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 not the probe mass.
- [Resize a satellite orbit](https://neetiitlab.com/physics/experiments/circular-satellite/): 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 negative.
- [Match a sidereal rotation](https://neetiitlab.com/physics/experiments/geostationary-match/): A geostationary satellite remains above one equatorial longitude only when its orbit is circular, equatorial, prograde and has the Earth’s sidereal rotation period. Changing the period produces longitude drift.
- [Stretch within the elastic range](https://neetiitlab.com/physics/experiments/stress-strain/): 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 the original length in this model.
- [Compare loaded wires](https://neetiitlab.com/physics/experiments/young-extension/): A long thin wire stretches more than a short thick wire under the same load. Modulus describes the material; the wire stiffness also depends on its dimensions.
- [Compress and shear a material](https://neetiitlab.com/physics/experiments/bulk-shear/): Bulk modulus describes resistance to volume change under uniform pressure. Shear modulus describes resistance to shape change under tangential stress. A negative volume strain indicates compression.
- [Watch sideways contraction](https://neetiitlab.com/physics/experiments/poisson-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 approximately (1−2ν)ε.
- [Store energy in a wire and beam](https://neetiitlab.com/physics/experiments/elastic-energy/): 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: greater depth sharply reduces bending.
- [Lower a pressure probe](https://neetiitlab.com/physics/experiments/liquid-pressure/): A deeper probe supports a larger liquid column and reads greater pressure. Density determines the slope. Container shape does not affect pressure at a given depth in the same connected liquid.
- [Link a pair of pistons](https://neetiitlab.com/physics/experiments/hydraulic-lift/): A pressure increase applied to a confined fluid reaches both pistons. The larger piston produces more force, but moves a smaller distance so the ideal lift conserves work.
- [Submerge a floating object](https://neetiitlab.com/physics/experiments/buoyant-objects/): 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 float freely in this model.
- [Drop a sphere through viscous liquid](https://neetiitlab.com/physics/experiments/stokes-terminal/): Weight, buoyancy and viscous drag determine a falling sphere’s speed. As speed grows, drag grows until the net force vanishes and the sphere reaches terminal speed. Viscosity lowers this limiting speed.
- [Find the pipe-flow transition](https://neetiitlab.com/physics/experiments/reynolds-flow/): Reynolds number compares inertia with viscous effects. A larger speed or diameter promotes transition, while higher viscosity favours laminar flow. The threshold is approximate rather than a universal switch.
- [Narrow a flowing pipe](https://neetiitlab.com/physics/experiments/bernoulli-pipe/): Continuity speeds up liquid where a pipe narrows. Bernoulli links this kinetic-energy increase and any height increase to a pressure decrease. The outlet area control changes both speed and pressure.
- [Drain a tank and compare lift pressure](https://neetiitlab.com/physics/experiments/tank-jet-lift/): A liquid head becomes jet kinetic energy, giving an exit speed proportional to the square root of head. In the separate air example, faster flow above than below gives lower pressure above and a net upward pressure force.
- [Stretch a two-sided liquid film](https://neetiitlab.com/physics/experiments/surface-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 distinguishes rise from depression in capillary systems.
- [Compare a drop and soap bubble](https://neetiitlab.com/physics/experiments/drop-bubble-pressure/): Surface tension makes the interior pressure exceed the exterior pressure. Smaller spheres need a larger pressure difference. A thin soap bubble has two interfaces and twice the excess pressure of a drop at the same radius and tension.
- [Change tube radius and wetting](https://neetiitlab.com/physics/experiments/capillary-rise/): Surface tension around the tube balances the weight of the raised liquid column. Smaller radius produces a larger rise. A contact angle above 90° reverses the sign, producing capillary depression.
- [Bring two blocks into contact](https://neetiitlab.com/physics/experiments/thermal-contact/): Temperature describes thermal state; heat is energy transferred because temperatures differ. The isolated blocks approach a common temperature determined by their heat capacities. Equal masses do not guarantee a simple average unless their specific heats are also equal.
- [Heat a solid, liquid and ideal gas](https://neetiitlab.com/physics/experiments/thermal-expansion/): Heating expands most materials, but coefficients and constraints matter. A solid’s volume coefficient is roughly three times its linear coefficient; a liquid has its own volume coefficient. A constant-pressure ideal gas volume follows absolute temperature.
- [Explore water near 4°C](https://neetiitlab.com/physics/experiments/water-four-degrees/): Water contracts when warmed from 0°C to about 4°C and expands when warmed further. Its density maximum explains why lakes can retain denser liquid below a colder surface.
- [Mix hot and cold materials](https://neetiitlab.com/physics/experiments/calorimetry-mixture/): A calorimeter balances heat lost against heat gained. A larger hot heat capacity pulls the final temperature toward the hot initial value. Specific heat has units J/(kg·K), while total heat capacity is mc.
- [Heat ice through state changes](https://neetiitlab.com/physics/experiments/latent-heating/): During melting or boiling, heat changes the state while temperature stays constant. Between state changes, heat increases temperature according to the relevant specific heat. The horizontal plateaus represent energy, not a failed heater.
- [Conduct heat through two layers](https://neetiitlab.com/physics/experiments/layered-conduction/): Thermal resistances in series add. The poorly conducting or thicker layer takes the larger temperature drop. In a steady state the same heat rate passes through both layers.
- [Trace buoyancy-driven circulation](https://neetiitlab.com/physics/experiments/convection-cell/): 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 exceeds the ideal onset in this schematic.
- [Shift a blackbody spectrum](https://neetiitlab.com/physics/experiments/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 Planck spectral radiance.
- [Track cooling toward ambient](https://neetiitlab.com/physics/experiments/newton-cooling/): 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 same law predicts warming.
- [Compare absorption and emission](https://neetiitlab.com/physics/experiments/kirchhoff-radiation/): A surface that absorbs strongly also emits strongly under matching conditions. In an enclosure of the same temperature, absorbed and emitted power balance for every absorptivity. Unequal temperatures produce a net exchange.
- [Compare three thermal states](https://neetiitlab.com/physics/experiments/zeroth-thermometer/): The zeroth law makes temperature a consistent comparison: two bodies that separately equilibrate with the same thermometer are at the same temperature as each other. Set both bodies to the thermometer reading to establish the relation.
- [Balance heat, work and internal energy](https://neetiitlab.com/physics/experiments/first-law-ledger/): The first law is an energy balance. Heat entering increases internal energy; work done by the gas decreases it. Compression has negative work-by and can raise energy even without heat.
- [Explore an ideal-gas state](https://neetiitlab.com/physics/experiments/gas-state/): Pressure, volume, temperature and gas amount are related by the equation of state. At fixed amount and temperature, doubling volume halves pressure. Internal energy of this ideal monatomic gas depends on temperature alone.
- [Compare isothermal and adiabatic paths](https://neetiitlab.com/physics/experiments/gas-process-paths/): An isothermal gas exchanges heat to keep its temperature fixed as it expands. A reversibly adiabatic gas receives no heat, so expansion work lowers its internal energy and temperature. The adiabatic pressure falls more steeply.
- [Trace a pressure-volume cycle](https://neetiitlab.com/physics/experiments/pv-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 work; reversing it requires work input.
- [Audit the direction of heat flow](https://neetiitlab.com/physics/experiments/second-law-transfer/): Conservation of energy alone permits either direction of heat transfer. The second law selects the spontaneous direction by requiring nondecreasing total entropy. Heat flows from hot to cold without external work.
- [Set the temperature limits of an engine](https://neetiitlab.com/physics/experiments/carnot-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 separation increases the ideal efficiency.
- [Compare fast and slow gas compression](https://neetiitlab.com/physics/experiments/gas-bulk-modulus/): A gas compressed without cooling becomes hotter and resists more strongly than a gas allowed to remain isothermal. Consequently its adiabatic bulk modulus is γ times its isothermal value at the same starting pressure.
- [Compress an ideal gas isothermally](https://neetiitlab.com/physics/experiments/ideal-gas-work/): Pressure rises as an isothermal gas is compressed. The work is the area under its inverse-volume pressure curve, giving a logarithm rather than simply multiplying one pressure by the volume change.
- [Link wall impacts to pressure](https://neetiitlab.com/physics/experiments/molecular-pressure/): Molecules transfer momentum when they bounce from a wall. Random isotropic motion makes the pressure depend on the mean squared speed. Temperature measures their average translational kinetic energy, not the speed of each molecule.
- [Change molecular mass and temperature](https://neetiitlab.com/physics/experiments/rms-speed/): An equilibrium gas has a distribution of speeds. RMS speed comes from the mean squared speed and exceeds the mean speed, which in turn exceeds the most probable speed. Lighter molecules move faster at the same temperature.
- [Distribute energy across active modes](https://neetiitlab.com/physics/experiments/equipartition-modes/): Equipartition assigns equal average energy to each active quadratic degree of freedom. Adding active rotational or vibrational terms raises total energy and heat capacity at the same temperature. A vibrational mode contributes two quadratic terms.
- [Compare monatomic and diatomic gases](https://neetiitlab.com/physics/experiments/gas-heat-capacities/): At constant pressure some heat supplies expansion work, so Cp exceeds Cv by R per mole. More active modes raise both capacities and bring their ratio closer to one.
- [Change molecular collision density](https://neetiitlab.com/physics/experiments/mean-free-path/): Mean free path is the average travel distance between molecular collisions. Higher number density or larger collision diameter makes collisions more frequent. Avogadro number converts the counted particles to moles.
- [Align periodic signals](https://neetiitlab.com/physics/experiments/period-frequency-phase/): Period measures the time between repeats; frequency counts repeats per second. Phase shifts the signal along time without changing its period. Watch the current-point marker as the same pattern repeats.
- [Project circular motion into SHM](https://neetiitlab.com/physics/experiments/circular-shm-projection/): 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 equilibrium position.
- [Twist a torsional pendulum](https://neetiitlab.com/physics/experiments/torsional-shm/): 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 shorter period.
- [Change a mass and spring](https://neetiitlab.com/physics/experiments/spring-oscillator/): A stretched spring pulls the mass toward equilibrium; a compressed spring pushes it back. The restoring force produces SHM. Mass and stiffness determine period, while amplitude determines the extent of the oscillation.
- [Track energy through one oscillation](https://neetiitlab.com/physics/experiments/shm-energy-exchange/): 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 changes twice during a complete oscillation.
- [Tune a small-angle pendulum](https://neetiitlab.com/physics/experiments/simple-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 small-angle period is independent of bob mass.
- [Drive an oscillator near resonance](https://neetiitlab.com/physics/experiments/driven-resonance/): A periodic force drives a damped oscillator most strongly near its resonance. Damping broadens and lowers the response peak. The settled motion lags behind the driving force; free oscillations decay with an exponential envelope.
- [Compare transverse and longitudinal motion](https://neetiitlab.com/physics/experiments/wave-particles/): A wave carries a disturbance through a medium. In a transverse wave particles move perpendicular to propagation; in a longitudinal wave they move parallel to it. Follow the highlighted particle to distinguish particle oscillation from the traveling pattern.
- [Control a traveling harmonic wave](https://neetiitlab.com/physics/experiments/travelling-wave/): The traveling-wave phase advances along the medium as time passes. Frequency sets the oscillation rate and wavelength sets the spatial repetition. Together they determine the propagation speed.
- [Overlap incident and reflected pulses](https://neetiitlab.com/physics/experiments/pulse-superposition/): 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 free-end reflection remains upright.
- [Identify string nodes and harmonics](https://neetiitlab.com/physics/experiments/string-standing-waves/): Two opposite traveling waves form a standing pattern with fixed nodes. Both fixed ends must be nodes, so only wavelengths 2L/n fit. Higher tension raises all harmonic frequencies; greater linear density lowers them.
- [Compare open and closed air columns](https://neetiitlab.com/physics/experiments/organ-pipe-harmonics/): An open end allows air displacement while a closed end constrains it. Two open ends support every integer harmonic; one closed end supports only odd harmonics. The mode index counts allowed modes, not necessarily harmonic number.
- [Combine nearby frequencies](https://neetiitlab.com/physics/experiments/beats-envelope/): Nearby tones alternate between constructive and destructive interference. The loudness envelope repeats at the difference frequency. The signed envelope has twice the intensity-peak spacing because positive and negative peaks both correspond to loud sound.
- [Change the speed of sound in a gas](https://neetiitlab.com/physics/experiments/gas-sound-speed/): Sound propagation depends on a gas’s adiabatic compressibility and density. In an ideal gas their pressure dependence cancels, leaving temperature, molar mass and heat-capacity ratio. Warm or light gases transmit sound faster.
- [Move a source and an observer](https://neetiitlab.com/physics/experiments/sound-doppler/): An approaching source compresses the wavefront spacing and raises observed frequency. An approaching observer meets wavefronts faster. Their velocities enter different parts of the sound Doppler formula because the medium defines a preferred frame.
- [Charge transfer and conservation](https://neetiitlab.com/physics/experiments/em-1-1/): Two identical conducting spheres share charge when joined. Move the equalisation fraction from separated to fully connected and check the conserved total.
- [Coulomb force](https://neetiitlab.com/physics/experiments/em-1-2/): Change signs to switch attraction and repulsion. Increase separation to see the force decrease with the square of distance. Positive force here means repulsion.
- [Superposition and charged ring](https://neetiitlab.com/physics/experiments/em-1-3/): 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.
- [Point-charge field and field lines](https://neetiitlab.com/physics/experiments/em-1-4/): 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.
- [Electric dipole field and torque](https://neetiitlab.com/physics/experiments/em-1-5/): Compare axial and equatorial fields and rotate a dipole in a uniform external field. The field falls as r⁻³ in the far-field approximation.
- [Electric flux and Gauss law](https://neetiitlab.com/physics/experiments/em-1-6/): Tilt an open surface to change its projected area. Closed-surface flux instead depends on net enclosed charge; external charges contribute zero net closed flux.
- [Gaussian wire, sheet and shell](https://neetiitlab.com/physics/experiments/em-1-7/): Switch the charge geometry. A wire gives a 1/r field, an ideal sheet gives a distance-independent field, and a shell gives zero interior field.
- [Potential of charges and dipoles](https://neetiitlab.com/physics/experiments/em-2-1/): 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.
- [Equipotential surfaces](https://neetiitlab.com/physics/experiments/em-2-2/): All points at one radius from a point charge have the same potential. Move between spherical surfaces to change potential; travel along one surface requires zero electrostatic work.
- [Charge and dipole potential energy](https://neetiitlab.com/physics/experiments/em-2-3/): Choose a point-charge pair or a dipole in an external field. Pair energy kq₁q₂/r can be positive or negative. Dipole energy −pE cosθ is lowest when aligned with the field.
- [Free charge in conductors and insulators](https://neetiitlab.com/physics/experiments/em-2-4/): Free charges redistribute in an electrostatic conductor until the interior field vanishes. A fixed uniform charge density in an insulating sphere instead gives an interior field proportional to radius.
- [Dielectric polarization](https://neetiitlab.com/physics/experiments/em-2-5/): Polarization slightly separates positive and negative bound charge. Compare a battery-connected capacitor, which holds voltage, with an isolated capacitor, which holds free charge.
- [Parallel-plate capacitance](https://neetiitlab.com/physics/experiments/em-2-6/): Increase area or permittivity to store more charge per volt. Increase gap to reduce capacitance. Connected and isolated cases obey different charge constraints.
- [Series and parallel capacitors](https://neetiitlab.com/physics/experiments/em-2-7/): Series capacitors share charge and split voltage inversely with capacitance. Parallel capacitors share voltage and their charges add.
- [Capacitor energy](https://neetiitlab.com/physics/experiments/em-2-8/): Energy resides in the electric field. A battery-connected dielectric insertion increases stored energy; inserting dielectric into an isolated capacitor decreases it.
- [Drift velocity and mobility](https://neetiitlab.com/physics/experiments/em-3-1/): A small average drift speed can produce appreciable current because a metal contains many mobile electrons. Electron drift is opposite to conventional current.
- [Ohmic and non-linear VI curves](https://neetiitlab.com/physics/experiments/em-3-2/): An ohmic element has a constant V/I ratio at fixed temperature. The illustrative filament model increases resistance with heating and bends the VI curve.
- [Resistivity and temperature](https://neetiitlab.com/physics/experiments/em-3-3/): Length and cross-section control resistance independently of the material resistivity. The linear temperature relation is valid over a limited range.
- [Electrical power and Joule heating](https://neetiitlab.com/physics/experiments/em-3-4/): The circuit converts electrical energy into heat. With fixed resistance, doubling voltage doubles current and quadruples power.
- [Resistance combinations](https://neetiitlab.com/physics/experiments/em-3-5/): Series elements carry the same current; parallel branches see the same voltage. The equivalent parallel resistance is below the smallest branch resistance.
- [EMF and terminal voltage](https://neetiitlab.com/physics/experiments/em-3-6/): EMF is energy supplied per unit charge inside the source. Internal resistance causes terminal voltage to drop when a load draws current.
- [Series and parallel cells](https://neetiitlab.com/physics/experiments/em-3-7/): 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.
- [Kirchhoff junction and loop rules](https://neetiitlab.com/physics/experiments/em-3-8/): One series resistor feeds two parallel branches. Changing one branch changes the node voltage and both branch currents. The readout verifies charge conservation at the junction.
- [Wheatstone and metre bridge](https://neetiitlab.com/physics/experiments/em-3-9/): 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.
- [Oersted current and compass](https://neetiitlab.com/physics/experiments/em-4-1/): A current produces magnetic field circles around a straight wire. Reversing current reverses circulation and compass deflection; the right-hand rule gives direction.
- [Biot–Savart circular coil](https://neetiitlab.com/physics/experiments/em-4-2/): Biot–Savart contributions from a circular coil add along its axis. Centre field grows with current and turn count and decreases with coil radius.
- [Ampere wire and solenoid](https://neetiitlab.com/physics/experiments/em-4-3/): Switch between a long wire and long solenoid. Ampere law yields an inverse-radius field around a wire and an approximately uniform interior field in a long solenoid.
- [Lorentz force and circular motion](https://neetiitlab.com/physics/experiments/em-4-4/): Only velocity perpendicular to B contributes to magnetic force. Parallel velocity gives no magnetic force. The magnetic-only circular radius is shown separately from the chosen electric force.
- [Wire force and parallel currents](https://neetiitlab.com/physics/experiments/em-4-5/): 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.
- [Current-loop torque and moment](https://neetiitlab.com/physics/experiments/em-4-6/): The magnetic moment points along the loop normal by the right-hand rule. A uniform magnetic field creates torque even though net translational force on the closed loop is zero.
- [Galvanometer and meter conversion](https://neetiitlab.com/physics/experiments/em-4-7/): A radial field makes coil torque proportional to current. Add a small parallel shunt for an ammeter or a large series resistor for a voltmeter. Values beyond 90° indicate overload in this ideal model.
- [Bar magnet and equivalent solenoid](https://neetiitlab.com/physics/experiments/em-5-1/): A bar magnet and a small current loop with the same dipole moment have the same far field. Field lines form closed loops; an isolated magnetic pole is absent from this model.
- [Magnetic dipole fields and torque](https://neetiitlab.com/physics/experiments/em-5-2/): Axial field magnitude is twice the equatorial magnitude at equal radius. A separate uniform external field rotates the magnet toward its minimum-energy alignment.
- [Dia, para and ferromagnetism](https://neetiitlab.com/physics/experiments/em-5-3/): Diamagnetic susceptibility is weak and negative; paramagnetic susceptibility is weak and positive. Ferromagnetism can be much stronger and nonlinear; this lesson uses an explicitly simplified temperature-dependent linear response.
- [Magnetization and temperature](https://neetiitlab.com/physics/experiments/em-5-4/): Higher temperature disrupts alignment. Paramagnetic χ follows a Curie law here; the illustrative ferromagnetic response loses its strong ordering above the chosen Curie temperature.
- [Faraday flux and induced EMF](https://neetiitlab.com/physics/experiments/em-6-1/): Hold coil geometry fixed and vary the rate of field change. A large but steady field gives zero EMF; changing field creates an induced voltage.
- [Lenz law direction](https://neetiitlab.com/physics/experiments/em-6-2/): The minus sign means the induced current creates a field opposing the change in flux. When increasing flux becomes decreasing flux, induced current reverses. Heating remains nonnegative.
- [Self and mutual inductance](https://neetiitlab.com/physics/experiments/em-6-3/): Inductance measures flux linkage per ampere. More turns increase self-inductance quadratically. Mutual inductance also depends on how well the two coils share flux.
- [Eddy-current magnetic braking](https://neetiitlab.com/physics/experiments/em-6-4/): A moving conductor develops eddy currents that resist motion. This effective-loop model shows increased braking with stronger field and smaller loop resistance.
- [RC, LR and LC transients](https://neetiitlab.com/physics/experiments/em-6-5/): 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.
- [AC peak and RMS](https://neetiitlab.com/physics/experiments/em-7-1/): RMS is the DC-equivalent heating value for a resistor. It is not the mean voltage of a symmetric sinusoid, whose mean over a whole cycle is zero.
- [Reactance, impedance and phasors](https://neetiitlab.com/physics/experiments/em-7-2/): Inductor reactance grows with frequency; capacitor reactance falls. Their signed difference determines phase, and the resistor sets the in-phase component.
- [Series LCR resonance](https://neetiitlab.com/physics/experiments/em-7-3/): Near resonance, inductive and capacitive reactances cancel. Resistance limits the current and controls peak width; small resistance makes a sharper resonance.
- [Power factor and reactive current](https://neetiitlab.com/physics/experiments/em-7-4/): 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.
- [AC generator](https://neetiitlab.com/physics/experiments/em-7-5/): Rotating the coil changes its projected area in the magnetic field. Faster rotation raises both output frequency and peak EMF. Maximum flux occurs when instantaneous EMF is zero.
- [Transformer turns ratio](https://neetiitlab.com/physics/experiments/em-7-6/): A transformer uses changing shared flux. Raising voltage reduces available current for a given transmitted power. Efficiency accounts for a lumped input-power loss.
- [LCR response to DC and AC](https://neetiitlab.com/physics/experiments/em-7-7/): Compare AC steady-state frequency response with switched DC subcircuits. The DC selector explicitly chooses RC, LR or ideal LC; it is not a full damped second-order LCR transient solver.
- [Displacement current](https://neetiitlab.com/physics/experiments/em-8-1/): A charging capacitor carries conduction current in its wires and equal displacement current through its gap. No charge carriers need cross the dielectric gap.
- [Transverse electromagnetic wave](https://neetiitlab.com/physics/experiments/em-8-2/): 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.
- [Electromagnetic spectrum](https://neetiitlab.com/physics/experiments/em-8-3/): Move continuously from radio to gamma rays. Frequency increases as wavelength decreases; photon energy rises with frequency. Spectrum boundaries are conventional and overlap between sources and uses.
- [Plane mirror reflection](https://neetiitlab.com/physics/experiments/plane-mirror-rays/): 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 object is in front.
- [Spherical mirror images](https://neetiitlab.com/physics/experiments/spherical-mirrors/): 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 produces parallel reflected rays.
- [Glass slab refraction](https://neetiitlab.com/physics/experiments/slab-refraction/): The ray bends toward the normal on entering glass and away on leaving. The parallel faces restore its original direction but shift its line sideways. Thickness changes shift while leaving the refraction angle fixed.
- [Curved boundary refraction](https://neetiitlab.com/physics/experiments/spherical-refraction/): Curvature and an index difference give an interface optical power. The focal object distance differs from the focal image distance because the two media have different indices.
- [TIR and fibre guidance](https://neetiitlab.com/physics/experiments/total-internal-reflection/): 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.
- [Lens shape and optical power](https://neetiitlab.com/physics/experiments/lens-maker-power/): Lens power comes from index contrast and both surface curvatures. Increasing curvature or index increases focusing power. Dioptres use focal length in metres.
- [Compound optical power](https://neetiitlab.com/physics/experiments/compound-optics/): Lens powers add in contact. Separation introduces an extra term and shifts the principal planes. A plane mirror immediately at a thin lens sends light through that same power twice.
- [Prism deviation and dispersion](https://neetiitlab.com/physics/experiments/prism-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 producing a larger minimum deviation.
- [Microscope and telescope](https://neetiitlab.com/physics/experiments/optical-instruments/): An objective and an eyepiece perform different jobs. The telescope compares angular sizes of distant objects. A microscope uses a real intermediate image before the eyepiece magnifies it.
- [Huygens wavefront refraction](https://neetiitlab.com/physics/experiments/huygens-wavefronts/): Every point on a wavefront acts as a source of secondary wavelets. A slower wave advances less far during the same time, tilting the new wavefront. The frequency remains fixed at the boundary.
- [Coherence and visibility](https://neetiitlab.com/physics/experiments/coherence-interference/): A stable phase relation preserves interference over time. Random relative phase washes out the cross term in the averaged intensity. Even perfectly coherent unequal sources do not reach complete darkness.
- [Young double-slit fringes](https://neetiitlab.com/physics/experiments/young-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 broaden fringes; slit separation narrows them.
- [Single-slit diffraction](https://neetiitlab.com/physics/experiments/single-slit-pattern/): 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 each adjacent order interval.
- [Polarizers and Brewster angle](https://neetiitlab.com/physics/experiments/polarizers-brewster/): The first polarizer selects a transverse direction. The analyzer passes the squared projection along its axis. At Brewster incidence, reflected and refracted rays are perpendicular and the reflected light is linearly polarized.
- [Photons build an interference pattern](https://neetiitlab.com/physics/experiments/photon-detection/): Each photon creates a localized detection while many detections reveal an interference probability pattern. Wavelength determines the energy and momentum of each photon, not whether the detector records a localized event.
- [Photoelectric threshold](https://neetiitlab.com/physics/experiments/photoelectric-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 threshold, while greater frequency raises maximum electron energy.
- [Photoelectric collecting curves](https://neetiitlab.com/physics/experiments/photoelectric-iv/): A retarding collector removes low-energy electrons first, reaching zero current at the stopping potential. An accelerating collector collects the available electrons, producing saturation. Intensity and frequency move different parts of the curve.
- [de Broglie wavelength](https://neetiitlab.com/physics/experiments/matter-wavelength/): Matter wavelength is set by momentum. Equal accelerating voltage gives equal kinetic energy to electron and proton, but their different masses produce different momenta and wavelengths.
- [Rutherford alpha scattering](https://neetiitlab.com/physics/experiments/rutherford-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 or larger incident energy reduces deflection.
- [Bohr hydrogen levels](https://neetiitlab.com/physics/experiments/bohr-hydrogen/): Bohr states have discrete energies and angular momenta. Larger n means a larger radius, lower speed and energy closer to zero. A bound state has negative energy relative to a separated electron and nucleus.
- [Hydrogen spectral transitions](https://neetiitlab.com/physics/experiments/hydrogen-spectrum/): A spectral line records the energy difference between levels, not the energy of either level alone. Downward transitions emit photons; upward transitions absorb matching photons. A set ending at n2 forms the Balmer series.
- [Hydrogen-like ions](https://neetiitlab.com/physics/experiments/hydrogen-like-atoms/): A stronger nuclear charge attracts the same single electron more tightly. At fixed n, radius decreases as1/Z and binding energy magnitude increases as Z². Hydrogen-like means one electron, including charged ions.
- [X-ray continuum and target lines](https://neetiitlab.com/physics/experiments/xray-cutoff-moseley/): 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 target line, once excitation is possible.
- [Nuclear size and composition](https://neetiitlab.com/physics/experiments/nuclear-composition/): Protons define an element; neutrons distinguish its isotopes. Nuclear radius grows with the cube root of nucleon number, making average nuclear density approximately constant. The strong interaction is short ranged.
- [Mass defect and binding](https://neetiitlab.com/physics/experiments/mass-defect-energy/): A bound system has less mass than its separated constituents. The mass difference corresponds to the energy needed to separate the nucleus. Atomic and nuclear mass conventions must not be mixed.
- [Binding energy per nucleon](https://neetiitlab.com/physics/experiments/binding-curve/): Intermediate nuclei have high binding per nucleon. Light nuclei can release energy by fusion and heavy nuclei by suitable fission when products have greater total binding. The curve is a trend, not a complete stability rule.
- [Fission and fusion energy balance](https://neetiitlab.com/physics/experiments/fission-fusion-q/): Nucleon number and charge balance before comparing masses. A positive Q is released energy for the specified products. Fusion and fission are different rearrangements but obey the same mass-energy accounting.
- [Alpha beta gamma changes](https://neetiitlab.com/physics/experiments/radiation-types/): Alpha is a helium nucleus, beta minus an electron from a nuclear conversion, and gamma a photon. Their charge and mass differ, producing different deflection and penetration behavior. Only gamma emission leaves both A and Z unchanged.
- [Decay populations and half-life](https://neetiitlab.com/physics/experiments/radioactive-populations/): Half-life is a population statistic. After each half-life the expected remaining count halves, while any small sample may fluctuate. Mean lifetime is longer than half-life and equals1/λ.
- [Bands and thermal excitation](https://neetiitlab.com/physics/experiments/energy-bands/): Allowed bands and gaps restrict electron states. A moderate gap permits thermally generated electron-hole pairs; a large gap suppresses them. A conductor needs available states near occupied ones, not simply a large number of electrons.
- [Intrinsic and doped carriers](https://neetiitlab.com/physics/experiments/semiconductor-doping/): Donors favor electrons and acceptors favor holes. Minority carriers remain present. At equilibrium the carrier product equals ni² in this nondegenerate model, and ionized dopants preserve overall charge neutrality.
- [Junction bias and diode IV](https://neetiitlab.com/physics/experiments/pn-junction-iv/): Forward bias lowers the junction barrier and narrows depletion; reverse bias widens depletion and usually permits only small leakage before breakdown. The threshold drawing is a simplified piecewise approximation.
- [Half and full-wave rectification](https://neetiitlab.com/physics/experiments/diode-rectification/): A half-wave circuit passes one polarity. A bridge reverses the negative half-cycle through the load, producing same-polarity pulses at twice the input frequency. Rectified output is pulsating before filtering.
- [LED photodiode and solar cell](https://neetiitlab.com/physics/experiments/optoelectronic-devices/): An LED converts forward electrical power to photons. A photodiode converts light to measurable current, commonly under reverse bias. A solar cell can deliver power to a load without an external bias source.
- [Zener load regulation](https://neetiitlab.com/physics/experiments/zener-regulator/): 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 output fall below breakdown.
- [Logic gates and truth tables](https://neetiitlab.com/physics/experiments/logic-gate-truth/): A truth table defines output for every input combination. Inverting gates reverse a basic logical operation. Checking every row avoids confusing OR with AND or NAND with NOR.
- [Vernier caliper](https://neetiitlab.com/physics/experiments/vernier/): 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 identifies the fractional part of a millimetre. A positive zero error makes the indicated value too large; subtract it.
- [Screw gauge](https://neetiitlab.com/physics/experiments/screw-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 adding the thimble reading. Correct a known zero error with its sign.
- [Irregular solid displacement volume](https://neetiitlab.com/physics/experiments/practical-3/): Use a graduated cylinder to measure a fully submerged irregular solid or lamina. The difference removes a common additive zero error; two rounded readings still contribute resolution uncertainty.
- [Spherometer curvature](https://neetiitlab.com/physics/experiments/practical-4/): 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.
- [Beam balance mass](https://neetiitlab.com/physics/experiments/practical-5/): Add known weights until the corrected pointer reaches zero. Equal arms compare masses directly; unequal arms need a lever-ratio correction.
- [Parallelogram force apparatus](https://neetiitlab.com/physics/experiments/practical-6/): Two measured string tensions add as vectors. A third string placed opposite the resultant balances the knot when its tension matches the resultant magnitude.
- [Pendulum length and stopwatch](https://neetiitlab.com/physics/experiments/practical-7/): 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.
- [Sliding and rolling friction](https://neetiitlab.com/physics/experiments/practical-8/): Tilt a surface until gravity exceeds the stated drag threshold. The rolling option models effective rolling resistance rather than detailed rotational inertia.
- [Incline spring-balance reading](https://neetiitlab.com/physics/experiments/practical-9/): A spring balance holds a block at rest on a frictionless incline. Plot holding force against sine of the incline angle to obtain a straight line of slope mg.
- [Paper scale least count](https://neetiitlab.com/physics/experiments/practical-10/): Choose the scale span and number of equal divisions before reading an object. Smaller divisions improve resolution only when the marks can be distinguished.
- [Metre-scale moments](https://neetiitlab.com/physics/experiments/practical-11/): Support a metre scale at its own centre of mass so its weight creates no moment. Adjust suspended masses or pivot distances to balance clockwise and anticlockwise moments.
- [Graph scales and error bounds](https://neetiitlab.com/physics/experiments/practical-12/): Select graph scale through the measured range, correct a systematic zero shift and compare resolution bounds with inferred slope. The plotted staircase shows finite instrument divisions.
- [Projectile range and protractor](https://neetiitlab.com/physics/experiments/practical-13/): Keep launch speed constant and sweep the protractor angle. Range peaks at 45° when launch and landing heights match. Complementary angles give equal ranges.
- [Double-incline energy transfer](https://neetiitlab.com/physics/experiments/practical-14/): Release a cart from rest on one slope and measure the rise on the second. Without losses it regains its original height irrespective of slope; friction lowers the return height.
- [Pendulum energy dissipation](https://neetiitlab.com/physics/experiments/practical-15/): 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 period.
- [Young modulus wire apparatus](https://neetiitlab.com/physics/experiments/practical-16/): Use a long thin wire to make elastic extension measurable. Diameter enters as a square, so its measurement strongly affects the inferred modulus.
- [Spring load–extension apparatus](https://neetiitlab.com/physics/experiments/practical-17/): 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.
- [Boyle-law gas syringe](https://neetiitlab.com/physics/experiments/practical-18/): Compress a sealed syringe slowly while holding temperature fixed. Its absolute pressure rises as volume falls; the PV product remains constant.
- [Capillary rise with detergent](https://neetiitlab.com/physics/experiments/practical-19/): Read the meniscus height above the reservoir. A smaller bore produces greater rise. The detergent selector demonstrates reduced tension using an explicit calibration factor.
- [Falling-sphere viscosity](https://neetiitlab.com/physics/experiments/practical-20/): Time a sphere only after it has reached terminal speed. Stokes law applies when Reynolds number is much smaller than one; the readout explicitly flags choices outside that regime.
- [Cooling-curve thermometer](https://neetiitlab.com/physics/experiments/practical-21/): Take temperature readings at equal time intervals and observe a decreasing slope as the body approaches room temperature. Correct a thermometer zero offset before fitting.
- [Solid and liquid calorimetry](https://neetiitlab.com/physics/experiments/practical-22/): 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.
- [Sonometer length and tension](https://neetiitlab.com/physics/experiments/practical-23/): 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 square root of tension.
- [Resonance-tube sound speed](https://neetiitlab.com/physics/experiments/practical-24/): 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 apparatus response parameter.
- [Wax freezing plateau](https://neetiitlab.com/physics/experiments/practical-25/): Follow cooling through a state change. Heat continues leaving during freezing while temperature remains near the model freezing point, because latent heat is released.
- [Bimetal-strip thermal bending](https://neetiitlab.com/physics/experiments/practical-26/): Bonded layers want to expand by different amounts. Their mismatch bends the strip. Reversing temperature change or swapping expansion coefficients reverses the bend direction.
- [Liquid expansion capillary](https://neetiitlab.com/physics/experiments/practical-27/): Warm a liquid-filled vessel with a narrow capillary. The observed rise reflects liquid expansion minus vessel expansion, so apparent expansion is smaller than true expansion.
- [Heat-loss surface factors](https://neetiitlab.com/physics/experiments/practical-28/): Compare surface area, airflow represented by h and emissivity. Radiation uses absolute Kelvin temperature, while convection uses temperature difference. This apparatus study compares instantaneous heat-loss rates.
- [Loaded metre-scale depression](https://neetiitlab.com/physics/experiments/practical-29/): Place a metre scale on two supports and add load at its midpoint. Depression grows with span cubed and decreases with thickness cubed; use modest loads within elastic bending.
- [Bernoulli flow apparatus](https://neetiitlab.com/physics/experiments/practical-30/): Narrowing a flowing tube raises speed and lowers pressure at equal height. Compare pressure-tube levels through the pressure-head readout; extreme invalid pressure predictions are flagged.
- [Wire resistivity VI graph](https://neetiitlab.com/physics/experiments/practical-31/): 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.
- [Metre bridge combinations](https://neetiitlab.com/physics/experiments/practical-32/): Slide the jockey until detector voltage reaches zero. Repeat with one resistor and its series or parallel combination; do not infer resistance from an unbalanced position.
- [Galvanometer half deflection](https://neetiitlab.com/physics/experiments/practical-33/): Adjust a shunt until deflection is half the unshunted reading. Then use the finite series-resistance correction to infer coil resistance and use original current per division for figure of merit.
- [Ammeter and voltmeter conversion](https://neetiitlab.com/physics/experiments/practical-34/): Choose the required range and derive the resistor to protect the sensitive coil. Check applied quantity against the chosen range before taking a reading; over-range values are visibly flagged.
- [AC sonometer resonance](https://neetiitlab.com/physics/experiments/practical-35/): Tune the bridge spacing while keeping tension and density fixed. Resonance occurs when the wire natural frequency matches the force frequency. An unbiased AC electromagnet attracts on both current polarities.
- [Core-dependent coil impedance](https://neetiitlab.com/physics/experiments/practical-36/): Compare current with and without the core at the same RMS voltage and frequency. The core raises inductance in this linear guide, increasing reactance and reducing current. Measure V/I rather than mistaking it for DC resistance.
- [Multimeter setup and reading](https://neetiitlab.com/physics/experiments/practical-37/): Meter function and connection must agree. Across-component voltage and series current are different measurements. Test continuity only in the source-off state, then compare a low resistance with an open component.
- [Bulb branches and fuse model](https://neetiitlab.com/physics/experiments/practical-38/): Each branch switch controls its own parallel bulb, while the common fuse controls both. Current demand is the sum of branch currents. Changing voltage changes power through the fixed hot-resistance guide.
- [Find a virtual circuit fault](https://neetiitlab.com/physics/experiments/practical-39/): Distinguish an open lead from a reversed source and a bypassed load. Correcting the selected fault restores the expected current. A negative meter reading can indicate reversed polarity rather than a failed load.
- [Wire probe potential gradient](https://neetiitlab.com/physics/experiments/practical-40/): 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 and therefore the gradient.
- [Concave-mirror u-v bench](https://neetiitlab.com/physics/experiments/practical-41/): Move the screen until its distance agrees with the calculated real-image position. Record object and image distances, then estimate focal length. An object inside focus yields no sharp screen image.
- [Convex mirror with converging lens](https://neetiitlab.com/physics/experiments/practical-42/): Use a convex lens to create a converging beam aimed at a point behind the convex mirror. Adjust mirror position until that point matches its centre of curvature. Normal incidence on the sphere makes rays retrace.
- [Convex-lens reciprocal plot](https://neetiitlab.com/physics/experiments/practical-43/): Obtain different sharp u-v pairs by moving the object and screen. Their reciprocals lie on a line. Reading the intercept provides another focal-length estimate.
- [Concave lens in a converging beam](https://neetiitlab.com/physics/experiments/practical-44/): A concave lens can yield a real final image when its incident beam is already converging sufficiently. The virtual-object distance must be signed, otherwise the focal calculation is wrong.
- [Prism minimum-deviation reading](https://neetiitlab.com/physics/experiments/practical-45/): 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 minimum overestimates the index.
- [Travelling-microscope slab readings](https://neetiitlab.com/physics/experiments/practical-46/): Focus successively on the lower mark, upper surface and apparent lower mark. Differences remove the arbitrary reference reading. Resolution and focus error influence the resulting index ratio.
- [Liquid lens with plane mirror](https://neetiitlab.com/physics/experiments/practical-47/): Find the no-parallax needle distance in air and with the liquid layer. The liquid layer has negative power in this geometry. The focal change and known curvature give the liquid index.
- [Forward and reverse diode meters](https://neetiitlab.com/physics/experiments/practical-48/): Reverse the virtual polarity and compare the voltage and current ranges. The resistor limits forward current. A reverse microamp reading is much smaller than the forward milliamps and needs a different meter scale.
- [Identify components and marking codes](https://neetiitlab.com/physics/experiments/practical-49/): Inspect the specimen shape and decode its markings. Resistor bands and capacitor digits encode values in different units. A diode stripe identifies a terminal rather than a resistance multiplier.
- [Diode and LED meter check](https://neetiitlab.com/physics/experiments/practical-50/): Use both lead orientations and compare silicon with an LED. A valid forward drop and reverse open indication are expected. An insufficient-compliance meter can show OL even for a working LED.
- [LDR lamp distance readings](https://neetiitlab.com/physics/experiments/practical-51/): Change distance while holding lamp output fixed. Illuminance falls with distance squared, while the resistance response is nonlinear. Read resistance rather than treating it as a direct light intensity.
- [Glass-slab pin and shift reading](https://neetiitlab.com/physics/experiments/practical-52/): The two outside pin lines should be parallel. Measure their shortest separation, not their horizontal coordinate difference. Compare this shift with Snell’s law and correct an introduced ruler offset.
- [Slit diffraction screen probe](https://neetiitlab.com/physics/experiments/practical-53/): 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 and distance fixed.
- [Collect an image on a screen](https://neetiitlab.com/physics/experiments/practical-54/): Change object location and move the screen to the real image. Lens and mirror send the outgoing light to opposite bench sides, even though their positive-distance equations share the same form.
- [Combined-lens focal measurement](https://neetiitlab.com/physics/experiments/practical-55/): Compare contact and separated holders. Touching lenses add power; a gap changes the system power and principal-plane location. Equal positive and negative contact powers make an afocal pair.
- [Cell EMF and internal factors](https://neetiitlab.com/physics/experiments/practical-56/): Read open-circuit voltage first, then close the load switch and observe terminal drop. Vary electrode spacing or immersed area to change internal resistance while holding the assigned EMF fixed.
- [LDR response to lamp power](https://neetiitlab.com/physics/experiments/practical-57/): Keep distance fixed while varying lamp power. The calibration converts lamp watts into illuminance at the sensor; the LDR converts illumination into nonlinear resistance. Compare this investigation with the distance experiment.
- [Transformer turns and RMS meters](https://neetiitlab.com/physics/experiments/practical-58/): 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 set actual current.
- [Hollow-prism liquid comparison](https://neetiitlab.com/physics/experiments/practical-59/): Use the same prism angle for two fluids and retune incidence for each minimum. The larger-index liquid produces a larger minimum deviation. Prism walls must be accounted for in a real apparatus.
- [Pith-ball polarization and contact](https://neetiitlab.com/physics/experiments/practical-60/): 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 weakens the induced-force guide.
- [Coil inductance geometry](https://neetiitlab.com/physics/experiments/practical-61/): Vary one geometric factor at a time. Turns enter quadratically; area and permeability linearly; length inversely. The negative induced emf expresses opposition to an increasing current.
- [Tangent-galvanometer alignment](https://neetiitlab.com/physics/experiments/practical-62/): Align the coil plane with the magnetic meridian, then infer horizontal Earth field from the deflection. Deliberate misalignment demonstrates why the perpendicular-field condition matters.
- [Zener reverse-breakdown meters](https://neetiitlab.com/physics/experiments/practical-63/): Raise the reverse source through breakdown while monitoring both meters. The diode voltage clamps approximately while resistor voltage and current increase. Compare two resistor settings at the same source.
- [Optical needle-parallax focus](https://neetiitlab.com/physics/experiments/practical-64/): Move the viewpoint sideways, then adjust the image needle until relative motion vanishes. Coincidence identifies image distance without requiring a screen. A stationary view cannot distinguish aligned but separate planes.
- [Post-office-box resistance balance](https://neetiitlab.com/physics/experiments/practical-65/): 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 calculate the unknown.
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- [Laws of Motion](https://neetiitlab.com/physics/chapters/11-04/): 9 free physics experiments and lesson notes for Laws of Motion, with model limits, worked examples and Tamil explanations.
- [Work, Energy & Power](https://neetiitlab.com/physics/chapters/11-05/): 8 free physics experiments and lesson notes for Work, Energy & Power, with model limits, worked examples and Tamil explanations.
- [Particles & Rotational Motion](https://neetiitlab.com/physics/chapters/11-06/): 10 free physics experiments and lesson notes for Particles & Rotational Motion, with model limits, worked examples and Tamil explanations.
- [Gravitation](https://neetiitlab.com/physics/chapters/11-07/): 7 free physics experiments and lesson notes for Gravitation, with model limits, worked examples and Tamil explanations.
- [Mechanical Properties of Solids](https://neetiitlab.com/physics/chapters/11-08/): 5 free physics experiments and lesson notes for Mechanical Properties of Solids, with model limits, worked examples and Tamil explanations.
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- [Thermal Properties of Matter](https://neetiitlab.com/physics/chapters/11-10/): 10 free physics experiments and lesson notes for Thermal Properties of Matter, with model limits, worked examples and Tamil explanations.
- [Thermodynamics](https://neetiitlab.com/physics/chapters/11-11/): 8 free physics experiments and lesson notes for Thermodynamics, with model limits, worked examples and Tamil explanations.
- [Kinetic Theory](https://neetiitlab.com/physics/chapters/11-12/): 6 free physics experiments and lesson notes for Kinetic Theory, with model limits, worked examples and Tamil explanations.
- [Oscillations](https://neetiitlab.com/physics/chapters/11-13/): 7 free physics experiments and lesson notes for Oscillations, with model limits, worked examples and Tamil explanations.
- [Waves](https://neetiitlab.com/physics/chapters/11-14/): 8 free physics experiments and lesson notes for Waves, with model limits, worked examples and Tamil explanations.
- [Electric Charges & Fields](https://neetiitlab.com/physics/chapters/12-01/): 7 free physics experiments and lesson notes for Electric Charges & Fields, with model limits, worked examples and Tamil explanations.
- [Potential & Capacitance](https://neetiitlab.com/physics/chapters/12-02/): 8 free physics experiments and lesson notes for Potential & Capacitance, with model limits, worked examples and Tamil explanations.
- [Current Electricity](https://neetiitlab.com/physics/chapters/12-03/): 9 free physics experiments and lesson notes for Current Electricity, with model limits, worked examples and Tamil explanations.
- [Moving Charges & Magnetism](https://neetiitlab.com/physics/chapters/12-04/): 7 free physics experiments and lesson notes for Moving Charges & Magnetism, with model limits, worked examples and Tamil explanations.
- [Magnetism & Matter](https://neetiitlab.com/physics/chapters/12-05/): 4 free physics experiments and lesson notes for Magnetism & Matter, with model limits, worked examples and Tamil explanations.
- [Electromagnetic Induction](https://neetiitlab.com/physics/chapters/12-06/): 5 free physics experiments and lesson notes for Electromagnetic Induction, with model limits, worked examples and Tamil explanations.
- [Alternating Current](https://neetiitlab.com/physics/chapters/12-07/): 7 free physics experiments and lesson notes for Alternating Current, with model limits, worked examples and Tamil explanations.
- [Electromagnetic Waves](https://neetiitlab.com/physics/chapters/12-08/): 3 free physics experiments and lesson notes for Electromagnetic Waves, with model limits, worked examples and Tamil explanations.
- [Ray Optics & Optical Instruments](https://neetiitlab.com/physics/chapters/12-09/): 9 free physics experiments and lesson notes for Ray Optics & Optical Instruments, with model limits, worked examples and Tamil explanations.
- [Wave Optics](https://neetiitlab.com/physics/chapters/12-10/): 5 free physics experiments and lesson notes for Wave Optics, with model limits, worked examples and Tamil explanations.
- [Dual Nature of Radiation & Matter](https://neetiitlab.com/physics/chapters/12-11/): 4 free physics experiments and lesson notes for Dual Nature of Radiation & Matter, with model limits, worked examples and Tamil explanations.
- [Atoms](https://neetiitlab.com/physics/chapters/12-12/): 5 free physics experiments and lesson notes for Atoms, with model limits, worked examples and Tamil explanations.
- [Nuclei](https://neetiitlab.com/physics/chapters/12-13/): 6 free physics experiments and lesson notes for Nuclei, with model limits, worked examples and Tamil explanations.
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