A : The geometrical shape of the wave front when a wavefront passes through a convex lens will be again plane wave front
R : Whne a plane wave front is reflected by a concave mirror, it remains as plane wavefront.

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. Both A and R are false

Answer

To analyze the statements A and R regarding wavefronts and their behavior when passing through a convex lens and reflecting off a concave mirror, we need to evaluate each statement separately.

### Step-by-Step Solution:

1. **Understanding Statement A**:
- Statement A claims that "the geometrical shape of the wave front when a wavefront passes through a convex lens will be again a plane wave front."
- When a plane wavefront passes through a convex lens, it converges to a point after passing through the lens. This means that the wavefront changes from a plane wavefront to a spherical wavefront as it converges. Therefore, Statement A is **False**.

2. **Understanding Statement R**:
- Statement R claims that "when a plane wave front is reflected by a concave mirror, it remains as a plane wavefront."
- When a plane wavefront strikes a concave mirror, it reflects and converges to a focal point, creating a spherical wavefront after reflection. Thus, the wavefront does not remain plane; it changes to a spherical wavefront. Therefore, Statement R is also **False**.

3. **Conclusion**:
- Both statements A and R are false. Therefore, the correct answer is that both statements are incorrect.

### Final Answer:
Both A and R are false.

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