Properties of Light: Wave-Particle Duality, Wavelength, Frequency, and Photon Energy

A set of vocabulary flashcards covering key concepts about light, including wave-particle duality, wave properties (λ, ν, amplitude), energy of photons, and interference/diffraction phenomena.

Wave-particle duality

The concept that light and other radiation exhibit both wave-like and particle-like properties.

Wavelength (λ)

The distance between two successive peaks of a wave.

Amplitude

Height of a wave from the centerline to its peak.

Frequency (ν)

The number of wave cycles (peaks) that pass a point per unit time; measured in hertz (s⁻¹).

Speed of light (c)

The speed of electromagnetic waves in vacuum; c ≈ 3.00 × 10^8 m/s; relates λ and ν via c = λν.

Inverse relationship between wavelength and frequency

As wavelength increases, frequency decreases, and vice versa; expressed by λν = c.

Planck's constant (h)

A constant linking energy and frequency: E = hν; h ≈ 6.626 × 10⁻³⁴ J·s.

Photon energy (E)

Energy carried by a single photon: E = hν = hc/λ.

Wavelength units

Measured in meters (m); often converted from nanometers (nm) to meters.

Frequency units

Measured in hertz (Hz) or s⁻¹.

Energy per photon vs energy per mole

Energy per photon is E = hν; energy per mole is Eₘₒₗ = E_photon × Avogadro's number (NA); often expressed in kJ/mol.

Avogadro's number (NA)

6.022 × 10²³ particles per mole.

Double-slit experiment

Experiment showing interference patterns, demonstrating wave-like behavior of light through diffraction and interference.

Diffraction

Bending of waves as they pass through a slit or around edges, leading to interference.

Constructive interference

Waves in phase overlap and add, producing brighter light.

Destructive interference

Waves out of phase cancel each other, producing darkness or reduced intensity.

In phase

Waves whose peaks (and troughs) align and overlap.

Out of phase

Waves whose peaks do not align, leading to cancellation when overlapped.

c = λν relation

The fundamental relation linking wavelength and frequency; their product equals the speed of light.

Energy from wavelength (E = hc/λ)

Energy per photon can be calculated from wavelength using E = hc/λ (equivalently E = hν with ν = c/λ).

Nanometer to meter conversion

1 nm = 1 × 10⁻⁹ meters; convert wavelengths to meters for calculations.

Energy units (Joules)

Energy is measured in joules (J); 1 J = 1 kg·m²/s²; used in E = hν and E = hc/λ.