Which of the following best explains light both as a stream of particles and wave motion ?

Options

A. `c = v xx lamda`
B. `lamda = (h)/(p)`
C. diffraction
D. photoelectric effect.

Explanation

To solve the question "Which of the following best explains light both as a stream of particles and wave motion?", we will analyze the given options based on the principles of wave-particle duality in light.

### Step-by-Step Solution:

1. **Understanding Wave-Particle Duality**:
- Light exhibits both wave-like and particle-like properties. This concept is known as wave-particle duality.

2. **Analyzing the Options**:
- **Option A: C = λν (C equal to velocity times wavelength)**:
- This equation represents the wave nature of light, where C is the speed of light, λ is the wavelength, and ν (nu) is the frequency. This option only explains the wave aspect of light.

- **Option B: λ and H = P**:
- Here, λ represents wavelength, H is Planck's constant, and P represents momentum. This option incorporates both wave (λ) and particle (P) aspects of light. The momentum of a photon can be expressed as P = E/c, where E is energy and c is the speed of light, linking particle properties with wave characteristics.

- **Option C: Diffraction**:
- Diffraction is a phenomenon that demonstrates the wave nature of light but does not address its particle nature.

- **Option D: Photoelectric Effect**:
- The photoelectric effect demonstrates the particle nature of light (photons) but does not explain its wave nature.

3. **Conclusion**:
- After analyzing the options, **Option B** (λ and H = P) best explains light as both a stream of particles (through momentum) and wave motion (through wavelength).

### Final Answer:
**Option B is the correct choice.**