(A ): E.M. waves can show diffraction effect (R) : E.M waves are transverse waves.

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.
B. Both 'A' and ’R' are true and 'R' is not the correct explanation of 'A
C. A' is true and 'R' is false
D. 'A' is false and R' is true

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the statement.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "E.M. waves can show diffraction effect."
- **Explanation**: Diffraction refers to the bending of waves around obstacles or the spreading of waves when they pass through small openings. Electromagnetic (E.M.) waves, which include visible light, radio waves, and X-rays, exhibit wave-like behavior. Therefore, they can indeed show diffraction when they encounter obstacles or apertures.

2. **Understanding the Reason (R)**:
- The reason states that "E.M. waves are transverse waves."
- **Explanation**: Transverse waves are those in which the oscillations are perpendicular to the direction of wave propagation. In the case of E.M. waves, the electric field (E) and magnetic field (B) oscillate perpendicular to each other and also to the direction of wave propagation. Thus, this statement is true.

3. **Evaluating the Relationship**:
- Now we need to determine if the reason (R) correctly explains the assertion (A).
- While both statements are true, the fact that E.M. waves are transverse does not directly explain why they can show diffraction. Diffraction is a property of waves in general, regardless of whether they are transverse or longitudinal.

4. **Conclusion**:
- Both the assertion (A) and the reason (R) are true.
- However, the reason (R) is not the correct explanation for the assertion (A).

### Final Answer:
Both A and R are true, but R is not the correct explanation of A.

---