Light and Photons Vocabulary

15 vocabulary flashcards covering key concepts from the notes on photons, spectra, and electromagnetic radiation.

Photon

The quantum of light; behaves as a particle and carries energy proportional to frequency (E = hv).

Photoelectric effect

Emission of electrons from a material when illuminated by light with enough energy to overcome the work function, demonstrating light’s particle nature.

Planck's constant

h, a fundamental constant equal to about 6.626 x 10^-34 J·s; links energy and frequency (E = hv).

Energy of a photon

The energy carried by a single photon, given by E = hv (and equivalently E = hc/λ).

Monochromatic

Light of a single wavelength (or frequency); examples include laser light.

Continuous radiation

Radiation that spans a broad range of wavelengths rather than discrete lines.

Emission spectrum

A spectrum showing bright lines at specific wavelengths emitted by excited atoms as they return to lower energy levels.

Absorption spectrum

A spectrum with dark lines where photons are absorbed by atoms at particular energies.

Hydrogen emission spectrum

The set of distinct emission lines produced by transitions of electrons in hydrogen atoms.

Standing wave

A wave pattern formed by the interference of two waves, with fixed nodes and antinodes.

Node

A point on a standing wave where the amplitude is zero.

Coherence length

The length over which a wave maintains a fixed phase relationship; lasers have long coherence length.

Laser

A device that emits highly coherent, monochromatic light with long coherence length.

Electromagnetic spectrum

The range of all electromagnetic waves arranged by wavelength or frequency.

Wave-particle duality

The concept that light exhibits both wave-like and particle-like properties (photons show particle traits; interference shows wave traits).