Photons

Definition

Photons are elementary particles that represent the quantum of electromagnetic energy. They have no mass and travel at the speed of light.

5 Must Know Facts For Your Next Test

1. Photons are responsible for electromagnetic radiation, including visible light, ultraviolet light, and X-rays.
2. The energy of a photon is given by the equation $E = h\nu$, where $h$ is Planck's constant and $\nu$ is the frequency of the radiation.
3. Photons exhibit both wave-like and particle-like properties, a concept known as wave-particle duality.
4. In atomic theory, photons play a crucial role in electronic transitions when an electron absorbs or emits energy.
5. The photon's momentum can be described using the equation $p = \frac{E}{c}$, where $E$ is energy and $c$ is the speed of light.

Review Questions

• What relationship does Planck’s constant have with a photon’s energy?
• How do photons contribute to electronic transitions in atoms?
• Explain wave-particle duality with respect to photons.

Related terms

Electromagnetic Spectrum:

The range of all types of electromagnetic radiation arranged by frequency or wavelength.

Wave-Particle Duality:

A fundamental principle stating that particles like photons exhibit both wave-like and particle-like properties.

Planck's Constant: $h$, a fundamental constant used to describe the sizes of quanta in quantum mechanics, approximately equal to $6.626 \times 10^{-34}$ Js.