Wave–Particle Duality: Matter Waves, Uncertainty, and Electron Microscopy

All flashcards

What is wave-particle duality?

It is the experimentally observed principle that matter and electromagnetic radiation can show wave-like or particle-like behavior depending on the experimental conditions.

What were Newton’s and Huygens’s competing models of light?

Newton described light as a collection of corpuscles, while Huygens described it as a wave.

What did Young’s double-slit experiment demonstrate?

It produced interference fringes, providing strong evidence that light behaves as a wave.

What is a photon?

A photon is an individual quantum, or packet, of electromagnetic radiation that can transfer energy in interactions such as the photoelectric effect.

Why was Thomson’s electron discovery important?

It showed that negative electric charge can travel through a vacuum in discrete units, identifying the electron as a particle.

Quiz questions

1. When electrons are sent through a double-slit apparatus one at a time, what happens as detections accumulate?Answer: An interference pattern gradually emerges from localized detection events.
2. Which relation gives a particle’s de Broglie wavelength in terms of its momentum $p$ and Planck’s constant $h$?Answer: $\lambda = \frac{h}{p}$
3. For two slits separated by distance $d$, which condition gives the angle $\theta$ of a bright fringe with order $n$?Answer: $d\sin\theta = n\lambda$
4. What does the uncertainty principle imply about position and momentum measured along the same direction?Answer: Their uncertainties satisfy $\Delta x\,\Delta p \geq \frac{\hbar}{2}$, limiting simultaneous precision.
5. An electron starts from rest and is accelerated through a potential difference $\Delta V$. What kinetic energy does it gain?Answer: $K=e\Delta V$