A: When soldier cross a bridge, they are asked to break steps.
R: If they do not break steps, then they will apply large force on bridge simutaneously.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to analyze the two statements provided:

**Statement A:** "When soldiers cross a bridge, they are asked to break steps."
**Statement R:** "If they do not break steps, then they will apply a large force on the bridge simultaneously."

### Step-by-Step Solution:

1. **Understanding Statement A:**
- Soldiers are instructed to break their steps while crossing a bridge. This is a common practice in military drills.
- The reason for this instruction is related to the concept of resonance. When soldiers march in unison, their footsteps can create vibrations that match the natural frequency of the bridge.

**Hint:** Consider the effects of synchronized movements on structures.

2. **Understanding Statement R:**
- Statement R claims that if soldiers do not break their steps, they will apply a large force on the bridge simultaneously.
- While it is true that marching in unison can lead to increased forces on the bridge, the statement implies that this force is the only concern. The critical issue is resonance, where the frequency of the soldiers' steps matches the bridge's natural frequency, potentially leading to structural failure.

**Hint:** Think about how forces and frequencies interact in oscillatory systems.

3. **Evaluating the Correctness of Statements:**
- **Statement A** is correct because breaking steps is a precaution against resonance.
- **Statement R** is misleading. While it is true that simultaneous steps can increase forces, the primary concern is the resonance effect, not just the force applied.

**Hint:** Differentiate between the implications of resonance and the general concept of force.

4. **Conclusion:**
- Since Statement A is correct and Statement R is incorrect, we conclude that:
- Assertion (A) is true.
- Reason (R) is false.

5. **Final Answer:**
- The correct option is that Assertion A is correct, and Reason R is incorrect.

### Summary of the Solution:
- Assertion A is true because it is a precaution against resonance.
- Reason R is false because it oversimplifies the situation by focusing only on force without addressing resonance.