Photon energy

Definition

Photon energy is the amount of energy carried by a single photon, proportional to its frequency and inversely proportional to its wavelength. It can be calculated using the equation $E = hf$, where $E$ is the photon energy, $h$ is Planck's constant, and $f$ is the frequency of the photon.

5 Must Know Facts For Your Next Test

1. Photon energy increases with increasing frequency and decreases with increasing wavelength.
2. The equation $E = hf$ relates photon energy to frequency, where $h$ (Planck's constant) is approximately $6.626 \times 10^{-34}$ Js.
3. In the photoelectric effect, photons must have enough energy to overcome the work function of a material to eject electrons.
4. Photon energy plays a crucial role in determining whether or not an electron will be emitted from a material when exposed to light.
5. The photoelectric effect provided essential evidence for quantum theory by demonstrating that light has particle-like properties.

Review Questions

• What equation relates photon energy to frequency?
• How does photon energy change with respect to wavelength?
• Why is photon energy important in understanding the photoelectric effect?

Related terms

Photoelectric Effect:

The phenomenon where electrons are ejected from a material when it absorbs light of sufficient energy.

Planck's Constant: A fundamental constant ($h$) used in quantum mechanics, approximately equal to $6.626 \times 10^{-34}$ Js.

Work Function:

The minimum amount of energy required to remove an electron from the surface of a material.