ConceptModern Physics
← All conceptsRelativity & duality (foundational)
two postulates of special relativity, time dilation / length contraction (qualitative), wave-particle duality and de Broglie matter waves
9 ways this goes wrong. Each one is a named misconception the questions are built to catch.
- Length contraction misdirectedContracts a moving object's dimension perpendicular to its motion, or expands it, instead of shortening only the length along the direction of motion.→
- Light speed frame-dependentAdds the source or observer velocity to the speed of light, violating the postulate that c is the same in all inertial frames.→
- Massless photon has no momentumConcludes a photon has zero momentum because it is massless, ignoring p=h/λ.→
- Only light has wave natureBelieves wave behavior applies only to light, not to electrons or other particles.→
- Photon has rest massAssigns a nonzero rest mass to the photon.→
- Time dilation reversedConcludes a fast-moving clock runs faster (rather than slower) as seen by a stationary observer.→
- Wave and particle seen at onceThinks a single experiment shows both wave and particle behavior simultaneously, ignoring complementarity.→
- de Broglie ignores speed/massComputes de Broglie wavelength without using the particle's momentum (mass times velocity).→
- de Broglie proportional to momentumTreats de Broglie wavelength as proportional to momentum rather than λ=h/p (inverse).→
