Photon

Definition

A photon is a quantum of electromagnetic radiation, essentially a particle of light. It has no mass, carries energy, and travels at the speed of light in a vacuum.

5 Must Know Facts For Your Next Test

1. Photons are the basic units that make up all forms of light.
2. They exhibit both wave-like and particle-like properties, a concept known as wave-particle duality.
3. The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength.
4. Photon interactions with atoms can result in various phenomena such as absorption, emission, and scattering.
5. In astronomical observations, photons carry information about distant celestial objects' composition, temperature, and motion.

Review Questions

• What is the relationship between a photon's energy and its frequency?
• How do photons demonstrate wave-particle duality?
• Why are photons important for astronomical observations?

Related terms

Electromagnetic Spectrum: The range of all types of electromagnetic radiation including gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves, and radio waves.

Quantum Mechanics: The branch of physics that deals with the behavior and interactions of particles on very small scales.

Spectroscopy: The study of the interaction between matter and electromagnetic radiation as a function of wavelength or frequency.