Which of the following relates to photons both as wave motion and as a stream of particles?

Options

A. interference
B. `E=mc^(2)`
C. Diffraction
D. `E=hv`

Answer

To solve the question, "Which of the following relates to photons both as wave motion and as a stream of particles?", we need to analyze the given options and determine which one exhibits the dual nature of photons.

### Step-by-Step Solution:

1. **Understanding the Dual Nature of Photons**:
- Photons exhibit both wave-like and particle-like properties. This concept is known as wave-particle duality.

2. **Analyzing the Options**:
- **Option A: Interference**:
- Interference is a phenomenon that occurs when two or more waves overlap and combine to form a new wave pattern. This is purely a wave phenomenon and does not relate to particle behavior.
- **Conclusion**: This option does not relate to photons as a stream of particles.

- **Option B: E = mc²**:
- This equation, formulated by Einstein, relates energy (E) to mass (m) and the speed of light (c). It implies that mass is a property of particles. Since photons are massless, this equation does not apply to them in the context of wave-particle duality.
- **Conclusion**: This option does not relate to photons as wave motion.

- **Option C: Diffraction**:
- Diffraction is the bending of waves around obstacles and openings. Like interference, it is a wave phenomenon and does not demonstrate particle behavior.
- **Conclusion**: This option does not relate to photons as a stream of particles.

- **Option D: E = hν**:
- This equation, known as Planck's equation, relates the energy (E) of a photon to its frequency (ν) with Planck's constant (h). This equation shows that photons can be described in terms of both energy (which relates to their particle nature) and frequency (which relates to their wave nature).
- **Conclusion**: This option relates to photons as both wave motion and a stream of particles.

3. **Final Answer**:
- The correct option that relates to photons both as wave motion and as a stream of particles is **Option D: E = hν**.