GRE Subject Test · GRE Physics

4:14 Topic 2 Electromagnetism Zero electric potential at a point does not mean zero electric field there: the field depends on how the… 3:48 Topic 3 Waves and optics Two individually bright waves can cancel at a point if their phases are opposite: crest meets trough. Th… 3:55 Topic 4 Thermodynamics and statistical mechanics Two engines can both conserve energy, yet only one respects the entropy limit on efficiency. This topic … 6:11 Topic 5 Quantum mechanics and atomic physics A particle in a box cannot have zero kinetic energy, even in its ground state: confining it changes whic… 4:22 Topic 7 Atomic spectra and selection rules Not every energy difference produces a strong spectral line. This topic relates atomic energy levels to … 4:04 Topic 8 Solid-state, nuclear and particle models A semiconductor's conductivity depends on the states and carriers available, not just on how many electr… 4:58 Topic 9 Hamiltonian mechanics and astrophysical scaling Energy methods connect a spring oscillator and an orbit, but their coordinates and assumptions differ. T… 6:31 Topic 10 Collisions, work and oscillator energy Two carts approach from different directions and stick. Their total momentum is conserved, but their kin… 5:36 Topic 11 Rotation, buoyancy and terminal-speed balances Turning a floating block upside down can change how much wood is submerged, even though the total weight… 6:14 Topic 14 Circuit power, induction and charged-particle motion A resistor in a parallel branch sees the branch voltage, which can differ from the battery voltage becau… 5:52 Topic 15 Maxwell waves, energy flow and boundary conditions A charging capacitor changes the electric field across its gap even though no conduction current crosses… 5:20 Topic 16 Acoustic Doppler echoes and standing-wave boundaries A driver hears the echo from a stationary wall at a shifted pitch, because the outbound and the returnin… 5:26 Topic 17 Optical instruments, path differences and refraction A gas cell in one arm of a Michelson interferometer is crossed twice, so counting only one passage halve… 5:36 Topic 18 Fourier symmetry and wave superposition A waveform can contain many harmonics and still have no sine terms at all: reflection symmetry tells you… 6:14 Topic 19 Gas processes, entropy and reversible cycles A refrigerator can move more heat than the work supplied to it. That ratio is a coefficient of performan… 5:41 Topic 20 Speed distributions and statistical ensembles A gas can have zero mean velocity while its particles have a large average speed: opposite directions ca… 6:16 Topic 21 Counting statistics, uncertainty and dimensional models A detector with ten percent efficiency does not register exactly ten photons out of every hundred: the c… 6:01 Topic 22 Relativistic lifetime, energy and Doppler shift A fast unstable particle can travel farther in the laboratory than its rest-frame lifetime times its spe… 6:02 Topic 23 Photoelectrons, reduced mass and atomic excitation Repeated, equally spaced current dips can mean the same excitation energy lost again and again, not a la… 6:31 Topic 24 Scattering, degeneracy and Pauli operators A quantum wave can reflect from a downward potential step, even though a classical particle has no turni… 6:16 Topic 26 Constraints, variational equations and cyclic coordinates A pendulum's string tension changes all through the swing, yet its equation of motion can be found witho… 6:05 Topic 27 Accelerating and rotating reference frames A person standing still on a turning platform still needs a real inward force, even though their acceler… 5:29 Topic 28 Fluid continuity, pressure energy and viscous flow A narrow pipe carries the same steady flow as the wide pipe feeding it, yet the pressure inside it depen… 5:59 Topic 29 Polarisation, magnetisation and material fields Sliding a dielectric into a capacitor changes the field one way if the battery has been disconnected and… 6:18 Topic 30 RC and RL transients, impedance and resonance A capacitor's voltage and an inductor's current cannot jump under an ordinary finite drive, yet the two … 6:15 Topic 31 Polarisation, analyser chains and phase Putting a third polariser between two crossed ones can let light through, although every filter only rem… 6:28 Topic 32 Diffraction envelopes and missing interference orders Two equal slits can have exactly the right path difference for a bright fringe and still send no light i… 6:38 Topic 33 Signed lens and mirror images A negative image distance is not a failed calculation to fix with an absolute value: it locates a virtua… 6:28 Topic 34 Thermal transport, calorimetry and expansion Two wall layers in series carry the same steady heat rate, yet the temperature can drop much more across… 7:16 Topic 35 Partition derivatives, energy fluctuations and heat capacity An energy gap keeps the heat capacity small at low and at high temperatures, even though the excited-sta… 6:41 Topic 36 Quantum occupations and limits of equipartition A fermion energy level can hold several particles when it contains several distinct states: the exclusio… 6:16 Topic 38 Exchange symmetry, spin pairs and Pauli exclusion Two electrons can share one spatial orbital, provided their combined space-and-spin state is antisymmetr… 7:41 Topic 39 Finite-well bound states and hydrogenic quantum numbers A bound wavefunction reaches outside a finite well, even though the particle's energy is below the poten… 7:50 Topic 40 Atomic field shifts and spectral differences The same magnetic field needs different quantum labels once its energy becomes larger than the spin-orbi… 7:47 Topic 41 Thermal spectra and one-electron scaling A spectral peak, a total radiated flux and the energy of one photon are three different things to measur… 5:44 Topic 42 Simultaneity, length measurement and velocity transformation Two observers can disagree about which of two events happened first, and both can be right. This topic t… 5:20 Topic 44 Radiation attenuation, laser gain and cavity modes A photon beam has no definite range, but a heavy charged particle does, and shielding calculations fail … 5:29 Topic 45 Bragg diffraction and electron-gas heat capacity Rotating a crystal in an X-ray beam maps its atomic planes, because strong reflection happens only at ce… 5:54 Topic 46 Reaction energies, activity and decay balances One atomic mass unit is 931.5 mega electron volts, so a reaction energy is a small difference between la… 6:44 Topic 47 Coordinate operators, separated modes and stable updates Writing the Laplacian of a radial function as f″ drops a term; the operator belongs to the coordinates, …