Glossary
Compton effect
The phenomenon where an X-ray photon scatters off an electron, resulting in the scattered photon having a longer wavelength (lower frequency) and demonstrating the conservation of momentum between the photon and electron.
Example:
When a high-energy X-ray photon collides with a stationary electron, the photon loses some energy and changes direction, a clear demonstration of the Compton effect proving photons have momentum like particles.
De Broglie wavelength
The wavelength associated with a particle, inversely proportional to its momentum, calculated using the formula $\lambda = h/mv$, where h is Planck's constant, m is mass, and v is velocity.
Example:
Even a baseball, if moving fast enough, theoretically has a de Broglie wavelength, though it's too small to be observable due to its large mass.
Diffraction
The bending of waves as they pass around obstacles or through small openings, causing them to spread out into the region behind the obstacle or opening.
Example:
When sound waves bend around a corner, allowing you to hear someone speaking before you see them, it's an everyday example of diffraction.
Interference
A wave phenomenon that occurs when two or more waves overlap, resulting in a new wave pattern where amplitudes either combine constructively (reinforce) or destructively (cancel).
Example:
The colorful patterns seen on soap bubbles are caused by the interference of light waves reflecting off the inner and outer surfaces of the thin film.
Relativistic mass-energy equivalence
The principle, described by Einstein's equation $E=mc^2$, stating that mass and energy are interchangeable and are different forms of the same fundamental entity.
Example:
In nuclear power plants, a tiny amount of mass is converted into a vast amount of energy, illustrating the profound implications of relativistic mass-energy equivalence.
Wave-particle duality
The fundamental concept in quantum mechanics stating that all matter and energy exhibit both wave-like and particle-like properties simultaneously.
Example:
An electron beam, typically thought of as particles, can produce an interference pattern when passed through a double-slit, demonstrating its wave-like nature.