Which of the following best describes the relationship between the frequency of a photon and its energy?

• A. The energy of a photon is inversely proportional to its frequency.
• B. The energy of a photon is independent of its frequency.
• C. The energy of a photon is proportional to the square of its frequency.
• D. The energy of a photon is directly proportional to its frequency.

Answer: (D)

Verified step by step guidance

1. Recall the fundamental equation that relates the energy of a photon to its frequency: \(E = h \nu\), where \(E\) is the energy, \(h\) is Planck's constant, and \(\nu\) (nu) is the frequency of the photon.
2. Understand that Planck's constant \(h\) is a fixed value, so the energy \(E\) changes directly with the frequency \(\nu\).
3. Analyze the proportionality: since \(E = h \nu\), if the frequency doubles, the energy also doubles, indicating a direct proportionality.
4. Compare this with other options: inverse proportionality would mean \(E \propto \frac{1}{\nu}\), and proportional to the square would mean \(E \propto \nu^2\), both of which contradict the fundamental equation.
5. Conclude that the correct description is that the energy of a photon is directly proportional to its frequency.