Wave-particle duality Flashcards – AQA A-level Physics (7408)

What is the de Broglie wavelength of a particle in terms of its momentum, mass and speed?

$\lambda = \frac{h}{p} = \frac{h}{mv}$ Here, $h$ is the Planck constant and $p = mv$ is the particle’s momentum.

How does a particle’s de Broglie wavelength change as its momentum increases or decreases?

Wavelength is inversely proportional to momentum: increasing momentum decreases wavelength, and decreasing momentum increases it.

For a fixed diffracting gap or spacing, how does wavelength affect the amount of diffraction?

A longer wavelength produces more diffraction; a shorter wavelength produces less.

When is particle diffraction most evident in relation to the gap or spacing size?

When the wavelength is comparable to the size of the gap or spacing.

How can observations and evidence change scientific knowledge over time?

They can lead existing explanations to be revised or extended.

Why has scientific understanding of the nature of matter changed?

Evidence revealed properties not captured by an exclusively classical particle picture.

What is peer review in science?

Other scientists scrutinise the evidence, methods and reasoning behind proposed changes.

What is the role of wider scientific examination and validation?

It helps establish whether findings and explanations are reliable.

Does peer review alone guarantee that a scientific claim is correct?

No. Peer review alone does not guarantee correctness.