According to Huygen's principle

Options

A. Each point of a wavefront is a source of secondary disturbance
B. The wavelets emanating from points on wavefront spread out in all directions with the speed of wave
C. The direction of ray is always in the direction given by tangent to the wavefront
D. Both (1) & (2)

Answer

To solve the question regarding Huygen's principle, we will analyze the statements provided and determine which ones are correct based on the principles of wave propagation.

### Step-by-Step Solution:

1. **Understanding Huygen's Principle**:
Huygen's principle states that every point on a wavefront can be considered as a source of secondary wavelets. These wavelets spread out in all directions with the same speed as the wave itself.

**Hint**: Recall that a wavefront is an imaginary surface representing points of a wave that are in phase.

2. **Analyzing the Options**:
- **Option A**: "Every point on a current wavefront acts as a source of secondary spherical waves or disturbance."
- This statement is true according to Huygen's principle.

- **Option B**: "Each point on the wavefront is the source of secondary wavelets which spread out in all directions with the speed of the wave."
- This statement is also true and aligns with Huygen's principle.

- **Option C**: "The direction of rays is always in the direction given by the tangent to the wavefront."
- This statement is misleading. While rays do indicate the direction of wave propagation, they do not only follow the tangent to the wavefront; they can be in various directions depending on the wavefront's curvature.

- **Option D**: "Both 1 and 2."
- Since both statements A and B are true, this option is correct.

3. **Conclusion**:
The correct answer is **Option D: Both 1 and 2**.

### Final Answer:
**D: Both 1 and 2**